Beneficiary Organisation Details
Slovenske Electrarne, Slovakia
http://www.seas.sk

CEZ, Czech Republik
http://www.cez.cz/eng
Project Aims
The objectives of the PH2.09/95 project for low power and shutdown states for VVER-440/213 were twofold:

• To perform the technical work related to development of low power and shutdown PSA for VVER 440/213 reactors;
• To transfer expertise in the area of PSA to the Beneficiary States;
• An important objective of the project was to adopt and to transfer Western knowledge relevant for the performance of a state of the art low power and shutdown (LPS) Level-1 PSA for the Bohunice V2 NPP (unit 3). Ultimately, the project was intended to generate low power and shutdown PSA models for the Bohunice NPP and assess its applicability for Dukovany NPP. This model had to be integrated with the full power PSA.

The project was also aimed at supporting the Dukovany national S-PSA project by providing input to a more comprehensive HRA study focused on shutdown operation. In addition, a study for Dukovany was intended to address the risk impact of sources of radioactivity other than that of the reactor core.
Project Results

• The point estimate for total core damage frequency (TCDF) from all shutdown internal events for the Bohunice V2 (unit 3 or 4) was calculated. This TCDF includes internal fire and flooding. The major contributors to the frequency of core damage (and damage of spent fuel located in the pool) were identified and evaluated in terms of initiating events, accident sequences, post operational states (POSs), systems, etc. Importance analyses and sensitivity analyses of key parameters were conducted to obtain additional insights. Potential plant modifications to reduce the risk were additional conclusions related to the Bohunice risk were drawn by comparing the Bohunice LPS PSA results with other PSA studies;
• In addition to the development of low power and shut down PSA models for Bohunice V2 NPP and proposing some actions to improve the similar models developed for NPP Dukovany, several activities have been especially designed and conducted to facilitate the transfer of know-how in the project subject area. They included conduct of several training events, transfer of written guidance and software for performance of specific shut-down PSA tasks and supervision of the actual work performed by the local sub-contractors – UJV REZ, VUJE and RELKO.

Further Project Results
a) See the attached file
b) Further information on the project results could be sought from the beneficiary organisations.