Planned activities to improve safety

As indicated, Slovenia plans to phase out nuclear energy in 2023. This nuclear power phase-out may induce problems on the personnel motivation and turnover and the recruitment of competent engineers. Is it planned to investigate this potential long-term problem?

Slovenia is aware of this problem. The motivation at the NPP is currently maintained by the other means such as higher incomes comparable to the local environment, highly professional work environment, etc. In any case some of the negative aspects of the personnel motivation will emerge, as the phase out will be coming closer. There is no systematic investigation on this problem yet to find the acceptable and effective solutions to this problem. It is fully agreed that this problem should be investigated before the consequences become unmanageable. After completion of the plant modernisation the action will be initiated to properly address this problem.

Many countries perform a complete safety review with a time period of 10 years, with the objectives of checking that the plant complies with the regulatory requirements, of re-analysing the operating experience and of examining how to take into account new safety concerns. Is Slovenia of the opinion that its strategy concerning safety reviews allows fulfilling these objectives?

SNSA has already followed the intention of the PSR. After the first ten year period SNSA requested from the NPP Krsko to perform complete PSA: level 1 and 2 for internal and external events and shutdown PSA and several deterministic analyses (Station Blackout, Fire Hazard, etc). The seismic input to the original design has been reinvestigated. Re-analysing the operating experience and examining how to take into account new safety concerns is a permanent function of the NPP Krsko and the SNSA. Checking that the plant complies with the regulatory requirements is a function of the SNSA. FSAR is regularly updated and subject to Regulatory Review to reflect all the changes made. 

Nevertheless Slovenia is considering inserting formal requirement for the Periodic Safety Review into new legislation which is under preparation.

Year 2000 Computer Issue

How does Slovenia ensure that the licensee has an adequate strategy and action plan in place to deal with the year 2000 safety issue?

The activities on the Y2K problem have started at the beginning of 1998. NPP Krsko was required to prepare and present to the Slovenian Nuclear Safety Administration (SNSA) an action plan to deal with the Y2K safety issue. The action plan was prepared based mainly on the guidelines and method definition documents of Nuclear Energy Institute: 

NEI/NUSMG 97-07: Nuclear Utility Year 2000 Readiness (October 1997)and 

NEI/NUSMG 98-07: Nuclear Utility Year 2000 Readiness Contingency Planning (Aug. 1998) and on the recommendations of the IAEA and EU. Besides reporting by the NPP Krsko to the SNSA the progress on the implementation of the plan is regularly inspected by the SNSA inspectors.

What is the schedule for completing the improvements programme for Krsko NPP? Are all the issues identified by the international missions and SNSA included?

In the report only the most relevant safety improvements were mentioned.

The complete improvements programme in the framework of the plant modernisation will be finished by the end of the year 2002. Full scope plant specific simulator will be operational by end of 1999, steam generator replacement and power upgrade will be completed in the year 2000. The complete list of issues identified by international missions is included. However improvement of the plant based on the feedback of international and internal operating experience is a permanent activity.

It is reported that almost all findings and recommendations from the ICISA mission have been resolved 1997. Which safety standards were used in the ICISA safety review? Are there still open issues? Which?

ICISA had no verified safety standards for its work. Members of the Commission were working based on their knowledge and experience. There is no major outstanding issue stil open. Steam generator replacement and installation of the plant specific full scope simulator are in progress and will be completed in the year 2000.

Which time schedule exist for the Fire Protection Action Plan introduced as a consequence of the PSA?

Based on the Fire PSA and Fire Hazard Analysis the Cost-Benefit analysis of safety improvements was performed resulting in Fire Protection Action Plan (FPAP). Three priority categories of modifications are established based on the contribution to the CDF and averted dose investment effectiveness. The first one is empty. That means that there is no modification which satisfies criteria of cost benefit effectiveness less than 1000 USD per person-rem dose reduction for modifications which reduce CDF > 1.0E-6 1Ry. The second one comprises the four sub-groups of modification that should be implemented up to the end of 1999. The third group (CDF< 1.0E-6 1/Ry) comprises approximately five sub-groups of modifications that should be implemented up to 2003.

Do the results of the NPP Krsko PSA study indicate need for additional seismic analysis? If yes, please indicate specifically what kind?

The PSA study itself didn't indicate any need of additional seismic analyses. The request or better suggestions came out from the IAEA technical review of the NPP Krsko PSA study. There it was recommended that additional geophysical and geological investigation of the vicinity of NPP Krsko should be conducted to reduce uncertainty related to seismic inputs. These investigations are in progress.

The US regulations have been followed in Slovenia. How these regulations, and their revisions, have been adapted in the Slovenian legislation? How the own needs and the development of technology and science in Slovenia are taken into account in the safety regulations, taking into account also severe accidents?

Licensing procedure for the NPP Krsko was executed in accordance with domestic legislation. Slovenia however has not developed specific standards, technical criteria and quality norms for the design and construction of nuclear facilities. In the case of Krsko NPP US codes and standards were applied directly during design, construction and commissioning. Essential licensing documents were PSAR and FSAR as per USNRC Regulatory Guide 1.70. During the operation Section 37 para 2 and 3 of the 1984 Act applies, which allows in such case that, technical criteria or quality norms and rules established by international or foreign technical regulations or international and foreign standards may be applied. 

Could you please provide a more detailed schedule for safety improvements mentioned in the report? Are there specific safety improvements for severe accidents? How the financing of planned safety improvements has been ensured?

NPP Krsko is continuously implementing safety improvements.

Planed safety improvements mentioned in the report are under implementation and will be completed by the year 2002. Detailed schedule is not presented because of its size.

There are several specific improvements for severe accidents. Replacement of both safety battery train?s with larger capacity, change of dry Rx cavity design with wet Rx cavity design and development of plant specific SAMG^s. 

Financing of planned safety improvements is ensured by yearly budget, which is proposed by plant management and approved by management board.