Foreword
General conclusions of WENRA on nuclear safety in EU candidate countries
Report

The Western European Nuclear Regulators' Association (WENRA) is the association of the Heads of nuclear regulatory authorities of Western European countries with nuclear power plants, namely Belgium, Finland, France, Germany, Italy, the Netherlands, Spain, Sweden, Switzerland ^(*) and the United Kingdom. The association has the following objectives:

• To develop a common approach to nuclear safety and regulation, in particular within the European Union,
• To provide the European Union with an independent capability to examine nuclear safety and regulation in candidate countries,
• To evaluate and achieve a common approach to nuclear safety and regulatory issues which arise.

The report is structured as follows:

• A foreword including background information, structure of the report and the methodology used,
• General conclusions of WENRA members reflecting their collective opinion,
• For each candidate country, an executive summary, a chapter on the status of the regulatory regime and regulatory body, and a chapter on the nuclear power plant safety status.

In order to produce this report, WENRA used different means:

• For the chapters on the regulatory regimes and regulatory bodies, experts from WENRA did the work,
• For the chapters on nuclear power plant safety status, experts from WENRA and from French and German technical support organisations did the work,
• Taking into account the contents of these chapters, WENRA has formulated its general conclusions in this report.

WENRA has not made a detailed safety assessment of the different nuclear power plants. Nuclear safety is a national responsibility and it belongs to the regulatory body of the various candidate countries to regulate the safety of all nuclear installations on their national territory, in line with the national legislative and regulatory framework.

WENRA's collective opinion on the regulatory systems is based on generic preconditions for an independent and strong regulatory regime such as a comprehensive nuclear legislation, the existence of an adequate licensing system, appropriate resources and technical support. WENRA's collective opinion on nuclear power plant safety is based on widely applied standards in Western European countries for the defence-in-depth and associated barriers. Quantitative comparisons of probabilistic safety assessments have not been used as the available results are of different depth and quality.

A first version of this report was issued in March 1999. It was solely based on the direct evidence WENRA had gathered through the different activities of its members (participation in multilateral assistance programmes, and in particular the Phare programmes and the IAEA extra-budgetary programme, and in bilateral contacts). In particular, information necessary to formulate an opinion on the regulatory regimes and the regulatory bodies were in many cases derived from the regulatory assistance projects of the RAMG implemented under the Phare programme. With regards to the safety status of nuclear power plants, WENRA had to recognise that in some cases the direct information was not sufficient to formulate an opinion.

For the present version, WENRA took the appropriate steps to collect the necessary information. In addition to the direct evidence already available, supplementary information was gathered through meetings with the candidate countries' regulatory bodies and plant operators. In particular, an ad-hoc Task Force was established to gather and evaluate additional information on VVER-440/230 reactors.

GENERAL CONCLUSIONS OF WENRA
ON NUCLEAR SAFETY IN CANDIDATE COUNTRIES TO THE EUROPEAN UNION

We, Heads of the Nuclear Regulatory Authorities assembled in WENRA, considering the status achieved on nuclear safety in the candidate countries to the European Union and taking into account the results of the investigations of experts from WENRA and from French and German technical support organisations, come to the following conclusions:
 

BULGARIA

Status of the regulatory regime and regulatory body

At present, the regulatory regime is not in line with Western European practice because it does not provide sufficient independence to the regulatory body. The resources of the regulatory body are also insufficient to allow it to carry out its responsibilities.

Nuclear power plant safety status

Kozloduy units 1-4 (VVER-440/230)
Although improvements have been made, the Kozloduy 1-4 units have not reached an acceptable level of safety. Among others, a concern remains about the ability of the confinement system to cope with the failure of the large primary circuit pipework. Even if a solution could be found to this issue, significant time and effort would be required to achieve the necessary improvements to bring them up to equivalent Western European reactor standards. The Bulgarian Government has announced its decision to close down Kozloduy units 1-2 before 2003.

Kozloduy units 5-6 (VVER-1000/320)
If their modernisation programmes are carried out properly, the Kozloduy 5-6 units should reach a level of safety comparable to that of Western European reactors of the same vintage.
 

CZECH REPUBLIC

Status of the regulatory regime and regulatory body

The regulatory regime and regulatory body in the Czech Republic are comparable with Western European practice. A well-defined licensing process according to Western practice is in place.

Nuclear power plant safety status

Dukovany units 1-4 (VVER-440/213)
Already in the early years of operation, improvements were implemented to remove safety deficiencies of the original design. An extensive modernisation programme has been established and it will allow Dukovany units 1-4 to reach a safety level comparable to that of Western European reactors of the same vintage. All issues, except the modernisation of the Instrumentation and Control systems, will be completed by 2004.

Temelin units 1-2 (VVER-1000/320)
The safety improvement programme for Temelin units 1-2 is the most comprehensive one ever applied to a VVER-1000 reactor. Standard Western practices were used to integrate Eastern and Western technologies and to deliver the corresponding authorisations. The on-going commissioning process has to confirm the integration of the different technologies. A few safety issues still need to be resolved. If these are resolved, Temelin units 1-2 should reach a safety level comparable to that of currently operating Western European reactors.
 

HUNGARY

Status of the regulatory regime and regulatory body

The regulatory regime and regulatory body in Hungary are comparable with Western European practice. A well-defined licensing process according to Western practice is in place.

Nuclear power plant safety status

Paks units 1-4 (VVER-440/213)
A major safety improvement programme has been implemented at Paks units 1-4, bringing these units to a safety level that is comparable to that of Western European reactors of the same vintage. An extensive modernisation of the Instrumentation and Control system is underway for further enhancement of safety.
 

LITHUANIA

Status of the regulatory regime and regulatory body

The legal and regulatory system has substantially developed over the past years. A licensing system is in place. However, further efforts are needed to reach a level comparable to Western European practice. In particular, the legal status of the plant need to be changed in such a way that operating organisation is given full responsibility and authority for the safety of the plant. The resources and technical support of the regulatory body need to be strengthened and its independence need to be maintained in the ongoing reorganisation of governmental institutions.

Nuclear power plant safety status

Ignalina units 1-2 (RBMK 1500)
The Ignalina units 1-2, although they have been much improved, cannot realistically reach a safety level comparable to that of Western European reactors of the same vintage. A decision has already been taken to shutdown unit 1 before 2005. The current financial situation of the plant needs to be improved in order not to delay the ongoing safety improvement programme.
 

ROMANIA

Status of the regulatory regime and regulatory body

Romania is taking the appropriate steps to establish a regulatory regime and regulatory body comparable with Western European practice. Further efforts are needed to ensure the necessary safety assessment capabilities, to develop the emergency response organisation within the regulatory body and to revise the pyramid of regulatory documents.

Nuclear power plant safety status

Cernavoda unit 1 (Candu 6)
The Candu 6 reactor of Cernavoda is similar to those in operation at Gentilly 2 and Point-Lepreau in Canada. The main concern is with the financial situation of the plant: under the current situation, the plant management may have serious difficulties in ensuring and maintaining an adequate level of safety.
 

SLOVAKIA

Status of the regulatory regime and regulatory body

The regulatory regime and regulatory body in Slovakia are comparable with Western European practice. However, the human and financial resources of the regulatory body need to be further improved in order to provide reasonable work conditions for the staff.

Nuclear power plant safety status

Bohunice V1 (VVER-440/230)
A major upgrade programme is nearing completion, which has made significant improvements to reactor safety. A concern remains about the ability of the confinement system to cope with the failure of the large primary circuit pipework. If a solution can be found to this issue, the plant should reach a safety level comparable to that of Western European reactors of the same vintage. The Slovak Government has announced its decision to close down these units in 2006 and 2008.

Bohunice V2 (VVER-440/213)
Since 1990, significant improvements have been implemented at Bohunice V2 (units 3-4). Once the on-going upgrading measures have been implemented, i.e. around 2002, the safety level of these units is expected to be comparable to that of Western European reactors of the same vintage.

Mochovce units 1-2 (VVER-440/213)
Compared to earlier reactors of the same type (VVER 440-213), the Mochovce units 1-2 included several modifications already at the design stage. Although some residual work is still needed to confirm all parts of the safety analysis, the safety level of the Mochovce units 1-2 is comparable to that of nuclear power plants being operated in Western Europe.
 

SLOVENIA

Status of the regulatory regime and regulatory body

In order to be fully comparable with Western practice, the nuclear legislation needs to be revised, addressing the identified deficiencies. The regulatory body has evolved and operates in general accordance with Western practice and methodologies, however the budget and financial situation need to be improved in order to increase its independent safety assessment capability.

Nuclear power plant safety status

Krško (Western PWR)
The Krško plant is a Western design pressurised water reactor and its safety level is comparable with that of nuclear power plants in operation in Western European countries. A large modernisation programme has been recently completed. The safety implications of the long-term plant ownership need to be assessed. In addition, the evaluation of a few technical issues needs to be finalised.

BULGARIA

Status of the regulatory regime and regulatory body

Since the early 1990s, there have been significant improvements in the legislative basis and in the capabilities of the nuclear regulatory body (the Committee on the Use of Atomic Energy for Peaceful Purposes - CUAEPP).

However, much remains to be done to bring the regulatory regime up to Western European standards. The Bulgarian Governments needs to enact legislation that will make explicit the independence of the CUAEPP from bodies concerned with the promotion of nuclear power. The government needs to provide adequate funding to the CUAEPP to enable the recruitment and retention of adequate numbers of qualified staff. Funding is also needed to enable the development new technical support facilities for the CUAEPP. Resources need to be committed to the drafting and introduction of necessary new and revised legislation.

Nuclear power plant safety status

There have been significant improvements in the standards of operational safety at all units and staff awareness of safety issues has demonstrably increased. However, the lack of Safety Analysis Report of any Bulgarian nuclear power plant is a serious shortcoming for judging the safety. Therefore to confirm the improvements implemented a consistent safety case has to be established and it has to be reviewed by the CUAEPP.

Kozloduy 1-4

Despite the significant safety improvements already achieved considering the present safety status of the plant, there are still some major safety issues which are closely linked to the original basic design of the VVER-440/230 reactors and which are difficult to be removed, such as the limited confinement function and capability and the vulnerability against common cause failures. The work at Kozloduy is at least three years behind that at Bohunice and consequently safety improvement is not as far advanced. At present in view of the large amount of work required to be carried out it is difficult to have a final judgement on the adequacy and feasibility of all measures foreseen. It seems, however that financial provisions for continued safety improvements are inadequate. For Kozloduy 1 and 2 the implementation of relevant measures cannot be expected taking into account the announced closure dates.

Kozloduy 5-6

An extensive programme for further upgrading of these units with assured financing has been reviewed by Western TSOs and is at an early stage of implementation. Safety assessments done by Western TSOs for similar plants indicate that with the completion of the planned safety upgrades, it could be possible to achieve a level of safety for units 5 and 6 which is in line with international recognised safety practices.

CZECH REPUBLIC

Status of the regulatory regime and regulatory body

The nuclear legislative framework in the Czech Republic is comparable with Western European practice. It is considered that the SÚJB has a status comparable to that of Western European regulatory bodies. The SÚJB has developed a series of regulatory practices, including a well-defined licensing process, which compare favourably with those of Western European nuclear regulators.

Further improvements could arise from the following suggestions. It is recommended that the Government of the Czech Republic consider giving high priority to the implementation of the new Act on emergency preparedness and planning. The SÚJB should be asked to make proposals in view of removing too detailed requirements from the high level documents of the regulatory pyramid. Also, the contracting rules of the SÚJB need to be adapted so that it can obtain, when appropriate, the necessary high quality technical support on a long term basis.

Nuclear power plant safety status

Dukovany NPP

In the early years of operation, modifications were carried out to remove safety deficiencies in the original design. An extensive modernisation programme, called MORAVA, will be implemented by 2004 with the exception of I&C replacement.

The safety culture appears to be adequate. Safety assessments and verification documents, e.g. periodic safety reviews, are conducted in a way which is comparable to Western practice.

After full implementation of the modernisation programme it is expected that Dukovany NPP will achieve a safety level comparable to that of NPPs of the same vintage operating in Western Europe.

Temelin NPP

The safety improvement programme for Temelin NPP is the most comprehensive which has been applied to a VVER-1000/320 plant.

International co-operation has had a considerable influence on the plant’s safety improvements (design, operation, safety approvals), and on the development of safety culture.

The combination of Eastern and Western technologies was successfully managed. Interfaces between the different technologies were considered throughout the modernisation programme and a standard Western practice was used to combine Eastern and Western technologies. The commissioning process will need to confirm the integration of the different technologies.

Some safety issues still need further clarification but if these issues are resolved, Temelin NPP will achieve a safety level that is comparable to that of operating Western PWRs.

HUNGARY

Status of the regulatory regime and regulatory body

The Hungarian approach to the licensing, regulation and control of nuclear facilities has developed strongly in the last ten years. A proper licensing process is in place, legislation and regulations are up-to-date, and the Hungarian regulatory practices are comparable with those of Western European countries.

However, there are some issues that need further consideration by the Hungarian Government. These are:

• The fact that the Minister of Energy Affairs is also the HAEC President creates an apparent conflict of interest, even though the formal mandate of HAEC President precludes this,
• The number of different authorities with direct responsibilities in the regulation of nuclear facilities increases the risk that important issues may be overlooked and reduces the efficiency of the regulatory work.

Nuclear power plant safety status

The basic technical structure of Paks NPP is good from the safety point of view and the key safety systems are comparable to Western plants of the same vintage. No major shortcomings in the present safety systems have been identified in any of the several, independent, in-depth assessments done so far. Also the performance of the bubbler condenser containment in the case of large break LOCA has been verified in full-scope tests. There is still need for detailed analysis of the experimental results and for complementary tests of other design basis accidents (steam line break and small LOCAs). Paks containment structures provide adequate protection against design basis accidents, and the overall radioactive releases would not be higher than what is accepted within the EU. However their leak rates are somewhat higher than those that are typical of Western European reactor containments.

Operational safety aspects are generally comparable to Western plants of the same vintage. However, management changes related to the political changes in the Government cause some concern. Periodic safety reviews are conducted in line with Western practices and have already led to an increase in safety.

It is expected that after the implementation of safety improvements already scheduled, the plant will reach a level of safety that compares favourably with plants of the same vintage in Western Europe.
 

Status of the regulatory regime and regulatory body

The legal and regulatory system has developed substantially over the last years. A licensing system is in place and the regulatory body VATESI has developed its approaches to safety assessment and inspection. Further efforts are needed, however, in order to be comparable with Western European practice.

The Lithuanian government needs to consider the legal status of Ignalina NPP, in order to give the operating organisation the full responsibility and authority to handle all financial and other management issues and thus to make the organisation able to take the full responsibility for safety. The legal obligation of VATESI to formally license suppliers needs to be changed, given a reasonable transition period. The imposed reduction of resources to VATESI, in terms of budget and staff, needs to be compensated as soon as possible and the resources successively strengthened in order for VATESI to handle all normal regulatory tasks and to contract the necessary technical support. In the reorganisation under way, of governmental institutions reporting directly to the Prime Minister, special attention needs to be given the independence of VATESI.

VATESI needs to give high priority to the development of the internal Quality Management system and take the final steps in separating the roles of the regulatory body and the operator in all supervisory activities.

Nuclear power plant safety status

The two units of Ignalina NPP (INPP) belong to the more advanced and improved design generation of RBMK reactors. In addition, the original design has been considerably improved through different safety improvement programmes. Most of the generic safety concerns with RBMK reactors have been satisfactorily addressed. More measures will be implemented, for instance the installation of a new diversified and independent shut down system at unit 2. However, weaknesses remain with respect to the last barrier for protection of the environment, especially in case of a severe accident. The weaknesses have to do with a less robust design of the confinement of the INPP reactors as compared with Western light water reactors. It is not realistic to make the INPP confinement system comparable. Consequently, regarding mitigation of accidents, a safety level comparable to light water reactors of the same vintage in operation in Western Europe will not be reached at Ignalina NPP. Therefore special attention needs to be given the prevention of accidents during the remaining operating time, including the need to ensure a high level of operational safety.

The financial situation of INPP needs to be much improved in order to cover all operational expenses as well as implementing the safety improvement measures considered necessary for the remaining operating time. Issues relating to safety culture need a stronger implementation. The symptom based emergency operating procedures need to be finalised and implemented without further delay. Due to the decision on decommissioning of unit 1, special attention needs to be given to keep a sufficient number of technical specialists, as well as maintaining the motivation of the staff, for the remaining operating time of both reactors.
 

Status of the regulatory regime and regulatory body

Romania is taking appropriate steps to establish a regulatory regime and a regulatory body comparable with Western European practice. Roles, duties and responsibilities of organisations involved in nuclear safety are in line with those assigned to similar organisations in Western Europe. The independence of the regulatory body from the organisations involved in the use and promotion of nuclear energy is fully established by the law and is sufficiently reflected in the practice. The regulatory regime and the regulatory body have both improved during the licensing process of Cernavoda NPP.

However some improvements are necessary to reach a situation comparable with the practice in Western European countries:

• The independent assessment capability, the inspection practice and the technical support of CNCAN need to be strengthened. The salaries at CNCAN need to be further improved to preserve suitably qualified staff. Adequate resources need to be assigned to set up and implement a training programme for new staff. Existing agreement with the Canadian nuclear safety authority needs to be more effectively used for training purposes and for seeking advice on regulatory issues specific of the CANDU technology. A strategic plan could support the assignment of existing limited resources to higher priority needs,
• National organisations that would have a role in a nuclear emergency need to make their emergency procedures and lines of communication more effective. In addition, CNCAN needs to further develop its competence and staff numbers in this area and establish an emergency response centre,
• The responsibility for auditing and approving vendors and suppliers should rest with the operating organisation and not with the regulatory body.

Romania has only one NPP into operation. It is a CANDU 6 reactor similar to those in operation at Gentilly 2 and Point Lepreau in Canada. The plant was constructed and commissioned under the responsibility of a Western Consortium (AECL, Ansaldo). The Cernavoda plant managers and operators have a professional attitude and have assimilated a western safety approach and culture.

It is important that the Romanian Government ensures that the current financial problems of the utility do not affect the ability of the management to maintain an adequate level of safety at the plant. Western support, especially from Canadian experts, should be made available when it is needed in the future.

Based on available information it is apparent that additional assessments are needed to confirm design safety margins against seismic events and the adequacy of fire protection. Also, the resolution of specific safety issues for similar plants that have been addressed or are currently under discussion in Canada need to be noted and incorporated where necessary into an improvement programme. The current high level of qualification and safety culture of the plant managers needs to be preserved in the longer tem. The plant management safety culture should be extended to all plant personnel and to the necessary service and support interfaces existing in the country. There is finally a need for improvement in some areas of plant operation such as training, emergency preparedness and accident management.
 

Status of the regulatory regime and regulatory body

The nuclear legislative framework in Slovakia is in line with Western European practice. The ÚJD has made significant progress over the recent years and has taken the appropriate steps to develop a series of regulatory practices comparable with those of Western European nuclear regulators. It is considered that, in general, the ÚJD status is comparable to that of regulatory bodies in Western European countries. On-going developments will improve its effectiveness.

It is recommended that the government of Slovakia consider the following suggestions. The ÚJD financial resources need to be further increased, in particular but not only, to maintain the independent assessment capability which was initiated under Swiss assistance. In order to retain highly qualified staff, the salaries at the ÚJD need to be made comparable with those of the operator's staff. It is suggested that the government give a high priority to the adoption of the national emergency plan. Also, the Atomic Act should be amended to remove some duties of the ÚJD that are not directly dealing with nuclear safety.

Finally, it is recommended that the ÚJD pay particular attention to ensure a clear separation between the technical support it receives and that provided to an operator.

Nuclear power plant safety status

The safety of Slovakian nuclear power plants has been improved since the early 1990´s in a determined manner with a strong national commitment, and significant investments have been made in technical upgrades. Guidance received from the IAEA has been used efficiently. Operational practices at all Slovakian nuclear power plants are consistent with those in Western Europe.

The following conclusions can be made:

Bohunice V1 (units 1-2)

The revised design requirements provide a coherent target for safety improvement of the plant. The utility has made significant progress towards establishing a new design base and implementing the relevant measures. Some work remains to be done but no technical obstacles in completing it are foreseen. It will be completed in 2000.

If a solution can be found to the concern related to the confinement ability to cope with the double ended guillotine break LOCA, the safety level of these units is expected to be comparable with that of units of the same vintage in Western European Countries.

Bohunice V2 (units 3-4)

Since 1990, significant improvements have been implemented at Bohunice V2. However, in order to achieve adequate reliability of safety systems in all operating situations, an extensive modernisation programme is planned for implementation between 1999-2006, with the major upgrades relating to safety being completed by 2002.

The safety of Bohunice V2 units seems generally adequate. Once the ongoing safety upgrades have been implemented (by about year 2002), the safety level of these units is expected to be comparable with that of units of the same vintage in Western European countries.

Mochovce (units 1-2)

Compared to their VVER-440/213 predecessors, units 1 and 2 of Mochovce included several modifications during the design phase. The most important of these are the use of higher quality equipment and the improvement of systems used in accident situations. However, some design weaknesses remained, and a dedicated nuclear safety improvement programme was developed for the Mochovce NPP in 1995. This programme, which is almost complete, was reviewed by Western European Technical Safety Organisations.

Although some residual work (e.g. bubbler condenser qualification, Mochovce site seismicity characterisation) is still needed to confirm all parts of safety analysis, the safety level of Mochovce units is comparable to that of the nuclear power plants being operated in Western Europe.
 

Status of the regulatory regime and regulatory body

The Slovenian Nuclear Safety Administration (SNSA) operates, in general, according to Western practice and methodologies. Since 1987, when the SNSA was established, it has evolved and matured as a regulator, with a clear separation between regulation and promotion of nuclear energy. The SNSA has a staff of motivated and dedicated persons with competence in their areas of responsibility. The SNSA has been assigned most of the roles and responsibilities normally allocated to a regulatory body. However, there are some issues that need to be addressed.

It is recommended that the Government of the Republic of Slovenia addresses the fact that the existing legislation on nuclear and radiation safety is not fully in line with current Western European practice, and its review needs to be completed. In addition, the lack of a final resolution of issues related to shared ownership of Krško NPP may affect the plant’s long term financial situation, and have an impact on safety. Furthermore, the legal and financial situation of SNSA needs to be improved in order to increase its independent safety assessment capability. Finally, the national response to nuclear and radiological emergencies needs to be improved by implementing an integrated national emergency plan, paying special attention to the interface with the Croatian authorities. The SNSA, on its side, needs to develop further its own technical capabilities in order to be able to make better independent decisions, and needs to continue defining its regulatory requirements to allow it to make the licensing decisions.

Nuclear power plant safety status

Slovenia has one nuclear power plant located in Krško. The design of the Krško NPP is similar to other Westinghouse PWRs of the same type operating in the USA, Belgium, Switzerland, Korea and Brazil. The safety of the Krško NPP is comparable to that of nuclear power plants of the same vintage into operation in Western Europe. The NPP has had a continuous backfitting and upgrading programme and a large modernisation programme, including the replacement of steam generators and a full scope simulator. The site organisation and the operational safety practice are similar to those in Western Europe.

For the future the following issues need to be addressed. The implications on safety of the ownership for the long term and the upcoming privatisation process of the energy sector need to be carefully assessed. In addition, efforts to strengthen the engineering capability of the utility need to be continued, including resources to ensure the necessary technical support from foreign organisations. Closer contacts with Western European utilities would also be beneficial. Finally, the evaluation of a few issues, like the seismic characterisation of the site and the onsite storage of spent fuel like need to be finalised and further attention is deemed necessary to the performance of a periodic safety review.
 

BULGARIA

Chapter 1: Status of the regulatory regime and regulatory body

Status of the legislative framework

1. The primary legislation for nuclear safety, the Act on the Use of Atomic Energy for Peaceful Purposes, was enacted in 1985 and amended in 1995 and 1998. Enforcing regulations, which give interpretation and meaning to the early primary legislation came into force in 1985 but, due to shortage of resources, there has been slow progress in making revisions to reflect the 1995 and 1998 amendments. The Act gives responsibility for licensing and regulation to the Committee on the Safe Use of Atomic Energy for Peaceful Purposes (CUAEPP).
2. A Programme on the Development of a Comprehensive Legislative Framework on Safety of Spent Nuclear Fuel and Radioactive Waste Management was adopted by the Council of Ministers in December 1999.
3. A three-year programme for the development and revision of much of the present regulatory documentation was agreed in 1998 by the nuclear regulator and relevant Ministries. This will lead eventually to greater consistency and facilitate the adoption of a less prescriptive regulatory approach. However, the high workload of the regulatory body means that this programme is already behind schedule and is likely to be delayed even further. In 1999 a new Act setting out further ambitious amendments to the earlier Act was developed by the CUAEPP in co-operation with other Ministries. However, this was rejected by the Council of Ministers in February 2000, which will delay improvements in the legislative basis by at least one year. The proposed amendments aim to bring about the harmonisation of the Bulgarian and West European legislation on the safety of nuclear facilities and in the field of accounting and control of nuclear material leading to less prescriptive Bulgarian nuclear legislation. A new Act on the safety in the use of Nuclear Energy is under development by a joint working group under the leadership of the CUAEPP. The new Act will cover in detail the management of radioactive waste, spent nuclear fuel and decommissioning of nuclear facilities. It will also establish a stable legal mechanism for the financing of the regulatory body.
4. Existing legislation adequately defines the legal obligations of the Operator (Kozloduy NPP) giving it responsibility for the safe control of the plant and for civil liabilities under the Vienna Convention. The primary legislation also requires the operating company to make payments into funds for dealing with radioactive waste and for decommissioning. The regulations to implement this came into force only in 1999 and the first contributions to this fund were made in the same year. Kozloduy NPP is wholly owned by the State.
5. All the key international conventions related to nuclear safety have been ratified and incorporated into national legislation.

 

6. The current legislation places a dual role on the CUAEPP. First as a State Body with membership from organisations concerned with the promotion of nuclear power and the operation of the power stations, and secondly as a legal entity charged with regulation of safety. This implies a lack of independence of the CUAEPP as a safety regulator. The Council of Ministers decided in April 1999 that the CUAEPP should be replaced by an Agency of the Government, the State Atomic Energy Agency (SAEA). This would ensure regulatory independence from those organisations promoting nuclear energy and would give SAEA sole responsibility for regulating the nuclear facilities and the storage and transport of nuclear material. However, the legislation to implement this was rejected in February 2000.
7. Funding for the CUAEPP comes from the State Budget and is controlled by the Ministry of Finance. It is currently inadequate. Budget restrictions imposed in 1996 reduced the CUAEPP staff by about 25% to 77. Of these, 50 posts were allocated to the Inspectorate on the Safe Use of Atomic Energy (ISUAE), the enforcement and inspection division of the CUAEPP. CUAEPP salaries are still approximately 20% of those in the nuclear industry, and this makes recruitment and retention of well qualified staff difficult. Currently, there are not enough staff to adequately carry out all necessary safety assessment and site inspection duties and the low salaries make the CUAEPP vulnerable to the loss of more experienced personnel. The training for inspectors and succession planning will need to be improved when resources are available. A Council of Ministers decision in April 1999 approved step by step increase of the CUAEPP personnel to 88 in 1999, 102 (currently 80) in 2000 and a figure of 110 is under negotiation for 2001. Proposed legislation would fix the regulator’s salaries at a minimum 80% of the equivalent industry level but this is not yet in place. Consequently the CUAEPP continues to lose staff.
8. In the past, frequent changes in senior management positions put additional strain on the CUAEPP. However, it is now benefiting from greater managerial stability, particularly with respect to the position of the Chairman. This is assisting the CUAEPP to plan and implement the improvement process.
9. Existing legislation gives the CUAEPP some enforcement powers. Penalties for contravention of regulations are defined in the primary legislation. Enforcement relies heavily on fines. The CUAEPP also has the responsibility to authorise suppliers of equipment to the licensees.
10. The CUAEPP currently has limited resources to perform technical evaluations and relies to a considerable extent on external support. In the last few years local technical support organisations have developed in number and expertise. However, there are still only a limited number in the country, which means they are sometimes contracted to work for both regulator and the utility. Following the enactment of the proposed new national legislation, the CUAEPP intends to have a permanent body dedicated to the technical support of the regulatory authority. There is currently a need for continuing external assistance and this need for support is unlikely to change in the near future.
11. The funds available to the CUAEPP for nuclear safety research and support are provided by charges levied on the licensees. Compared with equivalent funds typically available to Western regulators, this is at a fairly low level.
12. The status of the regulatory body is not yet comparable with its Western European counterparts. However, if political commitment would be achieved and resources made available, well-prepared plans exist to transform the CUAEPP.

 

13. An internally generated improvement plan issued by the CUAEPP in 1998 set out an ambitious programme for codifying the CUAEPP’s nuclear safety and licensing requirements. This will gradually replace the prescriptive legacy of the former Soviet Union and bring the Bulgarian regulator in line with a Western European approach. The aim is to create a strong and independent regulatory body with sufficient funding to carry out the full range of regulatory activities, including the making of regulations, site inspection, assessment and enforcing the utility to implementation of periodic safety reviews and draw up safety analysis reports as a basis for licensing. Some good progress has already been made, but unfortunately, because the CUAEPP has insufficient resources, implementation of the plan is already falling behind schedule. On the positive side, the CUAEPP is making much better use of its site inspectors by adopting a Western approach in which the licensee carries out routine, qualification inspections of pressure parts and lifting equipment, under a general supervision by the CUAEPP. The CUAEPP management has recognised the importance of introducing an internal quality management system and it is making progress in the development of a manual and documents to support the regulatory work.
14. In general, the CUAEPP is staffed by technically competent personnel. However, since 1992, due to the limited resources, the CUAEPP has had to rely on external independent technical assessments in carrying out the licensing of plant modifications and improvements. Much of this has been provided under assistance projects funded by the EC, the IAEA and bilateral programmes. In the absence of significant increases in CUAEPP resources, such assistance will continue to be needed, at least until the completion of the modernisation of units 5-6.
15. Regulatory decisions on the future upgrading of the Kozloduy units 1-4 need to be taken against a clear licensing plan which has yet to be fully established and implemented. This will require the development of the relationship between the utility and a competent and fully recognised regulator. At present the safety justification is expected to be completed in 2001. The CUAEPP needs to give clear guidance on the compliance targets with consistency between initiating event classification, analysis assumptions and acceptance criteria.

 

16. In the past there were too many regulatory documents, produced over a number of years, to provide for an effective, consistent emergency response. A new Regulation for Emergency Planning and Preparedness for Actions in Case of a Radiation Accident was approved by a Decision of the Council of Ministers in March 1999. This regulation defines the responsibilities for planning, advising and decision making in the case of a nuclear emergency. In October 1999 the CUAEPP started to up-date the National Emergency Plan for Action in Case of the Nuclear Accident at Kozloduy NPP. This is scheduled for completion at the end of 2000. The role of the CUAEPP will continue to be to monitor the situation and to give advice to the central committee which takes the decisions. The CUAEPP has received international assistance in the development of its own Emergency Preparedness Manual. The CUAEPP has completed the modernisation of its Emergency Response Centre (ERC) with new offices, a diesel-generator for emergency power supply and new telephone and computer systems. Bulgaria is a participant in the IAEA Regional Assistance Project to promote harmonisation of emergency planning in Central and Eastern Europe.
17. Currently, there are annual communications-only exercises involving all relevant national authorities, and there is a site emergency exercise each year. But the new emergency planning regulation requires a full national nuclear emergency exercise every 5 years. A full national emergency exercise will be organised following the bringing into operation of the upgraded ERC. Bulgaria has participated in the last three INEX-2 international exercises organised by the OECD.

 

18. There have been significant improvements in legislation, organisation and operation of the CUAEPP. However, many of the weaknesses identified previously still remain. Lack of progress in several areas is no doubt partly due to the severe economic situation facing the country. Low wages, combined with a high workload and poor working conditions, have a negative effect on staff morale and the loss of further valuable staff is likely.
19. In order to reach Western European standards, it is recommended that the Government of Bulgaria considers the following issues, several of which were addressed in the draft Act amending the CUAEPP that was rejected by the Council of Ministers in February 2000:
• There is no substitute for a strong, independent and competent regulator. Over recent years, the technical competence, strength and continuity of the Bulgarian regulator has been strongly supported by Western experts. Major efforts are still needed to ensure that the regulatory authority achieves a status that is comparable with that considered acceptable in Western European countries. The independence of the CUAEPP from bodies concerned with the promotion and supply of nuclear power needs to be made explicit,
• Managerial and organisational stability of the regulatory body should be maintained,
• Budget and salaries for the CUAEPP need to be increased to allow it to recruit and retain sufficient numbers of competent staff even though agreement has been given to increase staffing levels. In addition, the CUAEPP needs funds to obtain independent technical support when required and to support independent nuclear safety research,
• There remains a shortage of competent technical support organisations within the country. The technical capabilities available to the regulator need to be enhanced and should be independent from those used by the licensees.
20. In addition to the progress that has already been made, the CUAEPP needs to:

• Ensure that sufficient resources are committed to continue the drafting and introduction of new and revised legislation identified in the CUAEPP Improvement Plan, and to the programme for codifying CUAEPP’s basic nuclear safety and licensing requirements.

Data

1. On the site at Kozloduy, Bulgaria has in operation six nuclear power plants operated by the state owned company Kozloduy NPP. The Bulgarian Government has announced the closure of Kozloduy units 1 and 2 not later than 2003.



NPP unit	Reactor type	Start of construction	First grid connection	End of design life
Kozloduy 1 Kozloduy 2 Kozloduy 3 Kozloduy 4 Kozloduy 5 Kozloduy 6	VVER-440/230 VVER-440/230 VVER-440/230 VVER-440/230 VVER-1000/320 VVER-1000/320	1970 1970 1973 1973 1980 1984	1974 1975 1980 1982 1987 1991	2004 2005 2010 2012 2017 2021

2. On the Belene site, construction of two VVER-1000/320 units was started in the 1980’s but the work was frozen in 1990.

3. The main parts of the information summarised in this chapter are based on knowledge and experience acquired by the Technical Safety Organisations (TSOs) during the Kozloduy short term upgrading programmes in the early nineties and during the TSOs assistance to the regulatory body within the framework of EBRD's Nuclear Safety Account (NSA) programme.

 

 
 

Information on more recent issues was acquired during the WENRA-Task Force Mission in October 1999.
 

Design basis aspects

4. The first four units on the Kozloduy site are VVER-440/230 type nuclear power plants. Generic safety characteristics and safety issues of such plants are presented in Annex 2. Units 3 and 4 are more advanced type VVER-440/230 reactors having some of the design improvements of the later VVER-440/213. These include three-way redundancy and better segregation of safety systems, an Emergency Control Room and a low pressure core cooling system. During the early 1990's the utility implemented reconstruction programmes on all units based on IAEA recommendations and TSO advice. This involved installation of additional safety systems with the objective of eliminating or diminishing major safety shortcomings. The aim of these programmes was:
• To establish the Reactor Pressure Vessel status,
• To improve the behaviour of the confinement system,
• To improve the plant behaviour in respect of internal and external hazards,
• To improve systems and equipment reliability,
• To improve organisation and operational safety.

• To demonstrate the ability of the plant to cope with Loss of Coolant Accidents larger than the current (100 mm) Design Basis using conservative analysis; the licensing analyses of the new design basis accident (200 mm) have been performed and are currently under review at the CUAEPP,
• To demonstrate the ability of the plant to cope with the complete rupture of a main primary coolant pipe (as Beyond Design Basis Accident) using best estimate analysis; analyses are expected to be available by the end of the year 2000.

Reactor pressure vessel and primary pressure boundary

Confinement

Safety systems and hazards

I&C systems and emergency power supply

Beyond design basis accidents and severe accidents

In 1997 the utility proposed a more extensive safety-upgrading programme for units 1-4. Several modifications have already been introduced, with the aim of operating these units up to the end of their design life. This programme has undergone several updates, but has not been reviewed systematically by the regulatory authority. For internal review by the utility, a plant modification procedure exists in the frame of the NPP QA programme.

Safety assessment and documentation

Probabilistic safety assessment

Decommissioning

17. There have been significant improvements in the standards of operational safety at all units and staff awareness of safety issues has demonstrably increased.

 

 
 
 
 
 

Organisation, procedures, operation and maintenance

18. A number of upgrading measures have been fully implemented in Kozloduy units 1-4, or are well advanced:
• The training of existing and new personnel is now based on a systematic approach; management training has been introduced; operating personnel now have access to a modern multi-functional simulator of the Kozloduy training centre with well trained instructors,
• The technical specifications for operation have been significantly upgraded and are now unit specific,
• Symptom-oriented accident procedures for units 1-4 are under development in the frame of an international programme for VVER-440/230 reactors and are planned to be implemented by the end of the year 2000.


Safety culture and management, quality assurance

19. Since 1992, with Western assistance to the utility and the safety authority, plant management has pursued the objective of improving operational safety. The main goal of the management is to motivate personnel to continue the gradual increase in the safety and reliability of operation in order to reach a level comparable to Western practices. Results of the OSART mission of the IAEA to Kozloduy units 1-4 in January 1999 show that the status of operational safety has significantly improved. OSART gave a series of recommendations and encouraged NPP management to continue these improvements. A follow up OSART mission was agreed for the end of 2000.
20. There is competent staff at the plant dedicated to the continuous safety upgrading process. The management structure has been reorganised, the responsibilities clearly defined, and a Quality Assurance (QA) programme established. In the past the utility and the plant management have made significant progress in the implementation of a modern safety management system but improvements are still needed. In early 2000 the structure of previous NPP management (EP-1 and EP-2) was reorganised and now the units 1-4 (VVER-440) and units 5-6 (VVER-1000) have a common management.
21. The announcement of closure dates for units 1 and 2 present a new challenge for the utility and the plant management. Appropriate measures will be needed to ensure that motivation of staff for safe operation remains adequate during the remaining period of operation.

 

 
 
 

Operational experience

22. A systematic analysis of operational experience feedback (from Kozloduy and from other PWRs) has been ongoing since the early nineties.

 

 
 
 

Emergency preparedness

23. There is an on-site emergency plan in place. However, the national approach to emergency planning as a whole is currently under review.

24. The statements presented in this chapter regarding the safety of Kozloduy units 5-6 are based on the knowledge gained through active TSO involvement in the plant modernisation, IAEA mission records, and the information received through the VVER regulators forum.

 

 
 
 
 
 

 
25. The units 5-6 on the Kozloduy site are VVER-1000/320 type nuclear power plants. Generic safety characteristics and safety issues of such plants are presented in Annex 2.
26. In principle, the main safety features of units 5-6 are similar to the design of Western PWRs of the 1970’s. In the early years the units suffered from frequent disturbances mainly due to the low quality of some equipment. With the replacement of some control valves, such as Feed Water control valves and a number of items of I&C and electrical equipment, as well as modification of the Steam Generators, a reasonable performance has now been achieved. This is important for safety because the frequency of disturbances that might initiate an accident has been reduced.

 

 
27. A plant specific safety assessment is not yet available, although insights gained from TSO assessments of similar plants (e.g. Rovno 3) may be applicable to units 5-6. In developing the extended modernisation programmes for the VVER-1000 reactors, the utility has performed some plant specific safety analyses based on both deterministic and probabilistic approaches. But it has also used IAEA recommendations and operational experience at similar plants.
28. The PSA for Kozloduy units 5-6 is the first one performed in Bulgaria by its own experts. It is a level-1 study covering initiating plant events at full power, and also including fire and seismic events. It has undergone an IPERS mission review and a review by Western TSOs. In the frame of the modernisation programme, the operating organisation intends to adapt the PSA to the new plant status taking into account the TSO recommendations.
29. A programme for further upgrading of the units 5-6 is at an early stage and has been reviewed by Western TSOs. The main safety improvements relate to fuel and control rod optimisation, long term cooling including measures for prevention of sump filter clogging, electrical systems, instrumentation and control, containment integrity and radiation monitoring. The programme involves major Western and Russian partners and is planned for completion in stages over the next few years. Safety assessments by Western TSOs for similar plants in Ukraine and the Russian Federation have indicated that, after safety upgrading, it should be possible to achieve a level of safety in line with international recognised safety practices. However, to confirm this, a consistent safety case needs to be established and an adequate safety analysis needs to be made. Both will need to be reviewed by the CUAEPP.

 

 
30. Information and conclusions presented above for the Kozloduy 1-4 units are also generally applicable for units 5-6.

31. In Bulgaria there are only limited resources of independent technical support organisations in support to Kozloduy NPP. These include Energoproject Sofia, several institutes of the Academy of Science, Riskengineering, ENPRO consult and BEQE.

 

32. Spent fuel of the VVER-440 reactors is stored in an on-site fuel store erected in the 1980’s. For the VER-440 units there is currently an agreement with Russia which permits transport of this spent fuel back to the Russian Federation. Presently the spent fuel store is being modified to accept VVER-1000 fuel from units 5-6. This fuel is currently stored in pools within the containment and the storage space is nearly full. Radioactive wastes originating at Kozloduy are stored in interim storage facilities and an on-site cementation plant for liquid wastes is being built, although with considerable delay.

 

General remarks
33. There have been significant improvements in the standards of operational safety at all units and staff awareness of safety issues has demonstrably increased.
34. The lack of SAR is a serious shortcoming for judging the safety of NPP.

 

 
 
 

Kozloduy units 1-4

35. The short term upgrading measures implemented at units 1-4 have significantly improved the safety of these units. The measures taken so far have been directed mainly to the prevention of incidents and accidents.
36. Despite the safety improvements already achieved and considering the present safety status of the plant, there are still some major safety issues which are closely linked to the original basic design of the VVER-440/230 reactors and which are difficult to be removed. Among these are the limited confinement function and capability and the vulnerability against common cause failures. For Kozloduy 1-2 the implementation of relevant measures cannot be expected taking into account the announced closure dates.
37. Further safety improvements are being implemented or planned. The current safety-upgrading programme includes the extension of the design basis to a 200-mm break and the consolidation of the confinement system improvements. The utility and its technical support are motivated to the implementation of these improvements and have announced their intention to implement safety-upgrading programmes to mirror those that have been implemented at Bohunice V1. However, the work at Kozloduy is at least three years behind that at Bohunice and consequently safety improvement is not as far advanced.
38. In view of the large amount of work required to be carried out in the next modernisation stage it is difficult to have a final judgement on the adequacy and feasibility of all measures foreseen in this programme. It seems that financial provision for continued safety improvements are inadequate for Kozloduy 1-4.

 

 
 
 

Kozloduy units 5-6

39. In principle, the main safety features of these units are similar to Western PWRs. A programme for further upgrading of these units is at an early stage and has been reviewed by Western TSOs.
40. Safety assessments done by Western TSOs for similar plants in Ukraine and Russia indicate that, with the completion of the planned safety upgrades, it could be possible to achieve a level of safety for units 5-6 that is in line with international recognised safety practices. However, to confirm this, all safety measures from the programme have to be implemented and a consistent safety case has to be established. Both have to be reviewed by the CUAEPP.

1. Convention on Nuclear Safety (CNS), Answers to Questions on the National Report of Bulgaria, April 1999.
2. International Conference on the Strengthening of Nuclear Safety in Eastern Europe, Vienna 14 - 18 June 1999, IAEA-CN-75.

Chapter 1: Status of the regulatory regime and regulatory body

Status of the legislative framework

1. A new Atomic Act (law on peaceful utilisation of nuclear energy and ionising radiation) came into force in 1997. It confirms the SÚJB as the responsible body for supervising the utilisation of nuclear energy and ionising radiation. It defines the competencies of the SÚJB for the licensing of nuclear installations as well as the assessment, inspection and enforcement activities.
2. The Atomic Act states that the operator is responsible for the safety of its installations. The company that operates the nuclear power plants is a share holder company in which the state controls the major part.
3. Since the new Atomic Act came into force in 1997, the SÚJB has prepared or revised all regulations arising from the Atomic Act. The issuing of these regulations is an important accomplishment of the SÚJB.
4. The Czech Republic is a contracting party to all key international conventions dealing with nuclear safety.
5. The nuclear legislative framework in the Czech Republic is comparable with Western European practice.

6. The SÚJB is a central agency of the State Administration reporting to the Government. Its President may participate in the meetings of the council of ministers. If needed, the Vice-Prime Minister, in charge of economy and finance, ensures the link between the council of ministers and the SÚJB. The SÚJB is funded from the State budget, approved by the parliament.
7. The SÚJB is responsible for nuclear safety, radiation protection, transport of nuclear and radioactive material, international notification of incidents and accidents, the provision of information to the public, nuclear material accountancy, and the import and export of dual purpose equipment. The SÚJB plays an important role in the emergency preparedness and planning in conjunction with other administrative departments.
8. The SÚJB has the power to issue and withdraw authorisations. It also has the power to impose penalties on the operators for any violation of the conditions of an authorisation. Enforcement actions by individual inspectors can be appealed to the SÚJB President, the next level of appeal being the court of justice.
9. The SÚJB considers that its current budget is sufficient. It obtained a 13% increase in 2000 to facilitate the licensing work for the Temelin nuclear power plant. The SÚJB has a special budget for research, which is divided equally between radiation protection and nuclear safety. Certain administrative constraints arise for the SÚJB when it contracts for technical support. Except for small contracts or matters that are urgent from a safety point of view, the SÚJB is obliged to go through an open tendering process. This does not favour the long-term contractual technical support that the SÚJB needs.
10. The SÚJB was able to recruit 30 new staff over the last 3 years, which led to a total of 161 staff (as of 1^st January 2000) engaged on nuclear safety and radiation protection activities. The National Radiation Protection Institute, with a staff of 110 providing technical support on radiation protection, is under direct SÚJB supervision. From 1^st January 2000 another TSO with 45 staff came under the direct control of the SÚJB. Although its main field of operations is in the area of non-proliferation of nuclear, biological and chemical weapons, it also has considerable capabilities in the area of radiation protection and emergency preparedness.
11. Technical support for nuclear safety is provided by the Nuclear Research Institute (ÚJV), Institutes of the Academy of Science of the Czech Republic, universities, private companies and foreign organisations (for example from Slovakia). But there are a limited number of experts available from within the Czech Republic, which leads to the SÚJB needing to share competencies with the operators. Moreover, the contracting procedures with which the SÚJB must comply reduce the possibility of having long-term contracts for dedicated regulatory technical support. For the future, the SÚJB would prefer to replace some of the short-term contracts with individual contractors by long-term agreements with an extended scope of support. The administrative rules should be adapted in order to make this possible.
12. It is considered that, in general, the SÚJB has a status comparable to that of Western European regulatory bodies.

13. Since 1992, a number of national and international evaluations of the SÚJB have taken place. The recommendations of the various missions and support programmes have been used effectively in the development of Czech regulatory activities. The SÚJB takes an active part in international regulatory co-operation.
14. The Atomic Act authorises the SÚJB to draft subordinate regulations which, after approval by a legal advisory group of the Government, are signed by the SÚJB President. The laws and decrees issued in the Czech Republic contain very detailed requirements. The SÚJB needs to provide the Government with feedback on the application of the current regulatory pyramid and, if appropriate, propose the necessary changes. The SÚJB intends to continue developing technical guidance documents on the application of these regulations for the operators as soon as resources are available after the licensing of the Temelin nuclear power plant.
15. A well-defined licensing process for nuclear installations according to Western practice has been set up in the Czech Republic. It is governed by the Atomic Act and the Construction Act and includes the steps of siting, construction, operation and decommissioning. Major licences for siting, construction and permanent operation are issued by the District Authorities of the region where the installation is located. Such licences cannot be granted if the SÚJB issues a negative opinion regarding the safety of the plant. The District Authorities collect opinions from all other involved bodies of the state administration, including SÚJB. In addition to this process, there is a set of individual SÚJB approvals, which have to be granted (in accordance with the Atomic Act), for individual steps within the siting, construction, operation and decommissioning phases of a nuclear installation. The environment impact assessment, which is part of the licensing process, includes a statement on the decommissioning options.
16. The methodology for assessment of safety related documentation is derived from US NRC practice. In addition to the assessment of the safety analysis reports, the SÚJB also assesses and approves such documents as plant technical specifications, the physical protection plan and the utility’s quality assurance programme. Requirements for periodic safety reviews are included in licence conditions, usually requesting a review after 10 years of operation. However, when a plant is undergoing a modernisation programme, the periodic safety review is regarded as part of that programme.
17. The SÚJB inspection activities also derive from US NRC practices. They are based on a biannual inspection plan. The inspection plan and the inspection committees are the foundation of the SÚJB system of experience feedback. The SÚJB has established event-reporting requirements for the licensee and has developed a system for analysis and feedback of the licensee’s operating experience. This is similar to Western European practice. The SÚJB also actively participates in the INES and international event reporting systems. In addition to its participation in the VVER regulators’ forum, the SÚJB has an international agreement with Slovakia and Hungary to share the experiences gained at Dukovany, Bohunice, Mochovce and Paks.
18. The SÚJB has established two advisory committees, one for nuclear safety, the other for radiation protection. This provision is recognised as a good practice. In addition, special advisors have also been contracted for the licensing of the Temelin nuclear power plant.
19. In summary, the SÚJB has developed a series of regulatory practices that compare favourably with those of Western European nuclear regulators. The SÚJB is giving high priority to the licensing of the Temelin nuclear power plant and will resume the development of guidance documents after this period of intensive activities.

20. The new Act in the field of emergency preparedness and planning was passed by the Parliament in June 2000. In the case of an emergency situation of any kind, the co-ordination of all activities is the responsibility of the Inter-Ministerial Crisis Co-ordination Committee. This is composed of sub-committees such as the one for protection of the public, of which the SÚJB President is a member.
21. In the case of a nuclear emergency, the SÚJB has a role to advise the authority responsible for the protection of the public. To this end it has created an emergency response centre.
22. On-site emergency plans are approved by the SÚJB. It also ensures their consistency with the off-site plans that are approved by the head of the District Authority.
23. Neighbouring countries, e.g. Austria, have been invited as observers during emergency exercises. The national organisation for emergency preparedness needs to be further tested during exercises. However, the SÚJB considers that it will be difficult to test the national organisation in an exercise prior to the implementation of the new Act. The Czech Republic has participated in INEX-2 international exercises.
24. It is concluded that the SÚJB has taken the appropriate steps to fulfil its role in emergency preparedness.

25. The regulatory regime and regulatory body in the Czech Republic are comparable with those in Western Europe. Nuclear Safety legislation establishes the roles and responsibilities of the utility and the regulatory body. The regulatory body is well engaged in the state control of nuclear activities and the national emergency organisation is defined. A well-defined licensing process according to Western practice has been set up in the Czech Republic.
26. It is recommended that the Government of the Czech Republic consider the following:

• The implementation of the new Act on emergency preparedness and planning needs to be given a high priority,
• It seems that the documents in the regulatory pyramid in some cases may contain too detailed requirements. The SÚJB should be requested to suggest simplifications,
• The contracting rules of the SÚJB need to be adapted so that it can obtain, when appropriate, the necessary high quality technical support on a long term basis.

Chapter 2: Nuclear power plant safety status

Data

1. The Czech Republic has two nuclear power plants (NPP) at Dukovany and Temelin. Temelin NPP is the only plant within EU candidate countries, which is not yet in operation. Fuel loading of unit 1 started on 5 July 2000, fuel loading for unit 2 is planned to be approximately 15 months later.

NPP unit	Reactor type	Start of construction	First grid connection	End of design life
Dukovany: (in operation) Unit 1 Unit 2 Unit 3 Unit 4	VVER-440/213 VVER-440/213 VVER-440/213 VVER-440/213	1974 1978 1978 1978	02/1985 01/1986 11/1986 06/1987	2015 2016 2016 2017
Temelin: (under construction) Unit 1 Unit 2	VVER-1000/320 VVER-1000/320	1986 1987	Fuel loading 07/2000 11/2001	Design lifetime 30 years 30 years

2. The plants are owned by CEZ a.s. (Czech Power Company), a joint stock company. CEZ is the sole license holder for the construction and operation of nuclear power installations in the Czech Republic.

3. The information given in this report on Dukovany NPP is based on the general knowledge on VVER-440/213 plants (summarised in Annex 2), the Czech National Report for the Convention on Nuclear Safety (April 1999), IAEA documents and information provided by the SÚJB and the NPP.

 

 
 
 

The plant specific technical statements mainly rely on information provided by the operator on the occasion of a two days expert meeting with the SÚJB and the operator in June 1999 at Dukovany. Major safety issues were discussed and a summary list of upgrading measures (already implemented or planned in the near future) was provided by the operator. A second meeting of TSO expert organisations with the regulatory authority and the operator took place in May 2000. Since Dukovany NPP was not supported by large Western TSO projects in the past, both expert meetings were most worthwhile in providing technical information on the safety status of the NPP. Other background documentation which has been used is listed in the references.

An in-depth safety assessment of Dukovany NPP, in particular a review of the modernisation programme (MORAVA), has not been made by Western TSOs. The operator, however, offered to give further help in confirming and expanding the technical information on the plant's safety status given so far.

4. The initial design lifetime for each unit as a whole is 30 years from first criticality. For each of the reactor pressure vessels the design lifetime is 40 years.

 

 
Design basis aspects
5. All units of Dukovany NPP are second generation VVER-440/213 type reactors. Generic safety characteristics of these reactors are presented in Annex 2.
6. For the primary circuit and the safety-related systems, the basic design was made by Russian organisations. The specific plant design was developed and carried out by Energoprojekt Prague, a Czech company which, under Czech law, became the only responsible organisation for the design. All major parts of the primary equipment (except the main circulation pumps) as well as the equipment of the whole secondary circuit were manufactured in the former Czechoslovakia, mainly by Skoda Plzen, Vitkovice, etc. Domestic companies were also engaged in the quality control during manufacturing and construction. Since the nineties fuel manufacturing in Russia is also under Czech quality control. No major quality concerns have been identified in tests and inspections carried out since start of operation. Since the first years of plant operation, safety improvements have been made continuously. A major back-fitting programme had already started in 1991 based on the safety assessment of Greifswald unit 5, analyses and supporting programmes of the IAEA and WANO, and other international co-operation. Major safety improvements were focussed on fire protection, electrical supply, secondary side feedwater supply, and the installation of an emergency response centre. Further improvements are either under design or planned.

 

 
 
 
 

Reactor pressure vessel and primary pressure boundary

7. Reactor pressure vessel integrity (especially safety margins against radiation embrittlement) appears to be adequate for all units. Due to the well-balanced composition of material impurities (low content of Phosphorus, Copper) and the protection measures to lower the embrittlement rate, it is expected that annealing will not be necessary for any of the vessels during the design lifetime. To ensure pressure vessel integrity various measures have been introduced, e.g. low leakage core configuration and pressure vessel embrittlement monitoring by a surveillance programme. In-service inspections of the reactor pressure vessels and the primary piping are conducted with state-of-the-art techniques.
8. The piping systems were designed in accordance with Russian and Czech standards. A set of primary pipe whip restraints has been partially installed. A partial leak-before-break (LBB) implementation exists, but it is not relied upon in the safety case. Several preventive measures on steam generator (SG) integrity have been implemented or are underway (e.g. N16 activity measurement on each steam line, measures for exclusion of corrosion damage at flange connections, new feedwater distributors (inside the SG) in order to exclude primary collector thermal fatigue). Accident analyses have been performed and corresponding emergency operating procedures have been revised.
9. After completion of pipe whip restraints, the integrity of the primary pressure boundary is considered to be adequately safe.

 

 
 
 

Confinement

10. The leak rates have continuously decreased since the commissioning but they are still slightly higher than those that are usually accepted in Western PWR containments. For design basis accidents, however, radiological consequences would not exceed those accepted within EU countries. The performance of the bubbler condenser system in case of Large Break LOCA has been verified in full-scope tests in the frame of the Bubbler Condenser Experimental Qualification project sponsored by the EU. The test results for Large Break LOCAs were reported in early 2000. There is still need for detailed analysis of the experimental project results and for complementary tests for other design basis accidents.

 

 
 
 

Safety systems and hazards

11. In terms of capacity and redundancy the design of the safety systems is in general comparable to Western reactors of the same vintage (see Annex 2). Several measures against hazards (e.g. fire protection) have been taken in order to improve the separation between redundant trains. Further upgrading protection measures are completed or under way. Protection against sump screen clogging has been implemented. Secondary pipe whip restraints are scheduled to be added at the 14.7-m level in accordance with US standards, based on results of a recent analysis.
12. For improving the original generic VVER-440/213 design at Dukovany NPP, an independent Emergency Feedwater System has been installed in a separate building. Former shortcomings have been eliminated.
13. A systematic fire hazard analysis and a flooding analysis were carried out in 1997. Major weak points already have been eliminated (e.g. fire prevention measures). Further measures are underway or planned to be completed in 2000. Measures to cope with high-energy pipe breaks are under development, the completion is scheduled for 2003.
14. Seismic qualification of existing equipment is ongoing in the frame of the MORAVA Project; all new implemented equipment is qualified to withstand 0.1g which is acceptable for this site according to Western practice.

 

 
 
 

I&C systems and emergency power supply

15. Many improvements on I&C and electrical equipment have already been introduced or are underway. Based on insights gained from reliability analyses, proposals for modifications in the safety related I&C have been developed and will be implemented in 2001. Under current plans of the utility major upgrading of the I&C with digital systems is foreseen by 2010.
16. Various means for condition monitoring of mechanical components, e.g. vibration monitoring of reactor internals, lose part monitoring, on-line operational load measurement as well as ageing monitoring for key components, have been introduced.

 

 
 
 

Beyond design basis accidents and severe accidents

17. Analyses on some representative beyond design basis accidents (e.g. ATWS, total loss of heat sink, total loss of electrical power) were completed in 1998. The results of these analyses were used in the development of symptom based emergency operating procedures. Analyses on selected severe accidents with core melt scenario have been performed within the scope of a regional Phare project and in the frame of a level-2 PSA.

 

 
 
 
 
 
 

 
Safety assessment and documentation
18. In 1991 the former Czechoslovak Atomic Energy Commission (CSKAE) established conditions for licensing unit 1 for continued operation beyond 10 years (after 1994). In particular, this required the operator to provide a revised SAR, the so-called Operational Safety Analysis Report (OSAR). OSARs also have been prepared for units 2-4. Based on the OSAR, the SÚJB issues time-limited licences for further operation.

 

 
 
 

The structure and content of the OSAR are in compliance with the Regulatory Guide n°5 from 1988 and, to a major extent, with the later IAEA guide for periodic safety reviews (IAEA Safety Series 50-SG-O12).
 

19. All the modifications and safety improvements implemented at Dukovany NPP have to be included continuously in the safety analysis reports of the corresponding unit.

 

 
 
 

Probabilistic safety assessment

20. In 1992 the first version of a level-1 PSA study for Dukovany NPP was developed by Nuclear Research Institute Rez (NRI), in co-operation with several Czech and Slovak research institutes. In 1994 the updated level-1 PSA for Dukovany NPP was completed. The study was the first level-1 PSA completed for a VVER-440/213 reactor by a Western contractor. Since 1995 NRI has regularly updated the Dukovany level-1 PSA under a living PSA project. The current version of the level-1 PSA includes internal initiating events, fires and floods. The results were used for confirmation and scheduling of upgrading measures within the scope of the MORAVA programme (see § 24) and for refining of the emergency operating procedures. Finally in 1998 the level-1 PSA study was reviewed by an IAEA IPERS mission.
21. In addition, a shutdown PSA (SPSA) has been carried out. The results of the SPSA indicate that the contribution to the total core damage frequency is comparable with that of operation at full power. The results of the SPSA are being used to improve procedures for shut down accidental conditions. First results of a level-2 PSA study are already available and they will be used as an input for severe accident guidelines.

 

 
 
 

Safety measures and further assessments

22. The Dukovany NPP is involved in international co-operation. Several IAEA missions (OSART, ASSET, IPERS, etc.) have been performed to assess plant operational safety.

 

 
 
 

All important safety issues have been addressed in the existing safety programme and are either resolved or are underway. It is intended that the relevant measures will be resolved according to a schedule and will be complete by the year 2002 [1].
 

23. The Dukovany NPP is practising an extensive exchange with WANO and participates in common activities with other VVER-440/213 operators.

 

 
 
 

Programmes for safety improvements

24. An extensive modernisation programme (MORAVA) has been established based on Western nuclear safety standards and evaluation of operational experience [2]. The whole modernisation programme will be fully implemented by 2010. The major safety modifications, except I&C, will be completed by 2004. Upgrading of the safety related parts of the I&C with digital systems is planned to be implemented during refuelling outages and will be complete by 2010. The main objective of the programme is to achieve a safety level that is fully comparable with international safety standards and NPPs operating in EU countries.
25. Major upgrading measures which have already been implemented or are under way are for example:
• Automatic protection against primary circuit cold overpressure,
• Protection against sump screen clogging,
• Modification of equipment on the 14.7-m floor as pipe whip restrains, protection against missiles, replacement of valves, two additional steam relief valves, replacement and re-routing of pipes are under way,
• Modifications on the emergency feedwater system (e.g. pipe whip restraints, qualification of valves, et al.) are underway.

• Reconstruction and extension of diagnostic monitoring equipment,
• Installation of a full scope simulator.

Organisation, procedures, operation and maintenance
26. Staff responsibilities within the NPP are clearly defined. Nuclear safety and production are separate divisions within the management organisation. The head of the nuclear safety division is a deputy director.
27. Until now the plant operational personnel have been trained at the full-scope simulator of the VUJE Education and Training Centre (Slovakia). At Dukovany, a plant specific full-scope simulator has been installed and training is planned to start there from the beginning of 2001.
28. Symptom oriented emergency operating procedures (EOPs) have been developed in co-operation with Westinghouse. The new EOPs were fully introduced in November 1999.

 

 
 
 

Safety culture and management, quality assurance

29. The safety culture of Dukovany NPP has been continuously improved. Two OSART missions in 1989 and 1991 noted a high level of nuclear safety and a professional management with competent and trained personnel. A WANO peer review was performed in 1997.
30. A comprehensive quality assurance programme (QA) was established in compliance with IAEA recommendations and regulatory requirements. A management system has been set up in order to assess the safety significance of plant modifications and to ensure their proper implementation.

 

 
 
 

Operational experience

31. The reliability of plant operation since its first start-up is an indication of the good quality of the equipment.
32. Over the last ten years the average number of unplanned shutdowns (scrams) per unit has been less than 1 per year. A system has been established to ensure efficient feedback of operational experience from Dukovany NPP and other NPPs, especially from VVER reactors.

 

 
 
 

Emergency preparedness

33. The emergency plan is regularly updated and exercises are carried out annually. The Dukovany Crisis Centre is equipped with necessary computerised support systems. The level of preparedness achieved is adequate.

 

34. Originally it was planned to build 4 VVER-1000 type reactors at Temelin. Construction of the first two units started in 1986. In the early 1990s the original plan, however, was revised. In 1993 the former government decided to complete only units 1 and 2. This decision was re-approved last year by the current government.
35. Background information on Temelin NPP is available from several IAEA documents and to some extent from bilateral co-operation with institutions from EU countries. Furthermore additional generic information on the main safety features of VVER-1000 derives from Tacis and Phare projects on other VVER-1000 plants (e.g. Rovno 3, Kozloduy 5-6).

 

 
 
 

Several IAEA documents have been used for the assessment given in this chapter, e.g. IAEA report on VVER