STATE NUCLEAR REGULATORY INSPECTORATE OF UKRAINE

BOARD RESOLUTION

20 November 2012 Kyiv No. 14

On implementation of measures

identified upon stress tests

at operating NPPs of Ukraine

After the Fukushima-1 accident, Ukraine joined the initiative of the European Commission and European Nuclear Safety Regulatory Group (ENSREG) to perform stress tests based on the ENSREG stress test and peer review specifications (Declaration on Stress Tests, 24 June 2011).

The National Nuclear Operator Energoatom performed stress tests at operating NPPs, including the dry spent fuel storage facility at the Zaporizhzhya NPP. The stress-test results and relevant findings of nuclear and radiation safety review were discussed at open SNRIU Board meeting No. 13 on 24–25 November 2011. In addition, in January–March 2012, the stress-test results were subjected to EC peer review.

The recommendations provided in the final EC peer review report published on 4 October 2012 agree with findings of the state regulatory review on nuclear and radiation safety of stress-test reports. In particular, the following major recommendations can be pointed out for Ukraine:

-        implement measures to increase NPP seismic resistance on a systematic basis and in a timely manner under the Comprehensive (Integrated) Safety Improvement Program (C(I)SIP);

-        envisage measures for makeup of the primary system, steam generators and spent fuel pool in case of station blackout and loss of ultimate heat sink based on a thorough analysis of the use of mobile equipment;

-        in terms of severe accident management, demonstrate performance of key functions needed for severe accident management (hydrogen control, primary pressure decrease, containment overpressure protection, habitability and accessibility of the main and emergency control rooms etc.).

Therefore, the importance and relevance of the NPP safety upgrades included in the C(I)SIP were confirmed and additional measures were identified.

The National Nuclear Operator Energoatom introduced appropriate amendments and revised the priorities of C(I)SIP measures. The amendments to the C(I)SIP were agreed upon with the SNRIU. The revised C(I)SIP was approved by Cabinet Resolution No. 1270 dated 7 December 2011.

Following the reports by Ukrainian National Operator Energoatom and the State Enterprise State Scientific and Technical Center for Nuclear and Radiation Safety (SSTC NRS) on the status of post-Fukushima safety improvement measures at operating NPPs, the SNRIU Board states the following:

-         most post-Fukushima measures are still conceptual, no specific design features or analytical justifications have been developed. There is no stage-by-stage schedule of measures, so efficient stepwise monitoring by the SNRIU is impossible;

-         in spite of the measures taken to define a common technical policy, such as, for example, the decision of the joint SNRIU and Energoatom meeting of 26 June 2012, there are some distinctions between individual NPPs with similar facilities and issues;

-         seismic levels of the Khmelnitsky, Rivne and Zaporizhzhya NPP sites are not determined finally. The situation is most critical for the Zaporizhzhya site since its seismic investigations were not conducted in required scope. According to different sources, the seismicity of the Zaporizhzhya site may reach seven to eight magnitudes (from 0.1g to 0.2g);

-         the computer models being used to justify organizational and technical measures on severe accident management have not been validated;

-         there are no well-grounded decisions on the implementation of a filtered containment venting system;

-         primary system makeup in case of an accident involving station blackout and/or loss of ultimate heat sink has not been analyzed in detail as a measure intended to mitigate accident consequences;

-         there is no strategy for corium confinement within the reactor pressure vessel and containment.

In order to perform C(I)SIP measures in a timely and efficient manner (Operator), organize their efficient monitoring (SNRIU) and implement recommendations of the stress-test peer review for Ukrainian NPPs, the SNRIU Board

RESOLVES TO:

1.           Oblige the National Nuclear Operator Energoatom to develop a stage-by-stage schedule for implementation of post-Fukushima measures (indicating timeframes for modification stages in accordance with regulation NP 306.2.106-2005) and submit it to the SNRIU for review.

Deadline: 15 December 2012

2.           Oblige the National Nuclear Operator Energoatom to justify the seismicity of the Zaporizhzhya NPP site and seismic margins for the Zaporizhzhya, Khmelnitsky and Rivne NPPs using available data.

Deadline: 31 December 2013

3.           Oblige the National Nuclear Operator Energoatom to develop and agree additional measures for the Comprehensive (Integrated) Safety Improvement Program for severe accident management:

-         validate computer models;

-         implement strategies for corium confinement within the reactor pressure vessel and containment;

-         qualify equipment required for severe accident management for harsh environments;

-              analyze in detail the potential for primary system makeup in case of an accident involving loss of power and/or ultimate heat sink.

Deadline: 31 December 2012

4.           Oblige the National Nuclear Operator Energoatom to submit a well-grounded technical decision on implementation of a containment venting system in a prompt manner for review.

5.           Recommend the National Nuclear Operator Energoatom to analyze findings of the stress tests, peer reviews and measures planned at European WWER NPPs and Russian NPPs as well as EC reports and IAEA plans.

Board Chairperson O. MYKOLAICHUK

Board Secretary   I. SEMINOG