December 1999 Highlight

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Ukraine United States Cross-Cutting Activities Planned Activities

Ukraine

Participants review safety parameter display system projects for Ukraine's VVER-1000 reactors

To assess progress and develop plans for calendar year 2000, the steering committee for Ukraine's VVER-1000 safety parameter display system projects held a mid-December meeting. Committee members from Ukraine include representatives of Energoatom, the Nuclear Power Plant Operational Support Institute, Westron, and Khmelnytskyy, Rivne, South Ukraine, and Zaporizhzhya NPPs. U.S. team members represented Westinghouse Electric Company, Pacific Northwest National Laboratory, and Burns & Roe Enterprises, Inc. Burns & Roe hosted the three-day meeting at its facilities in Oradell, New Jersey.

Highlights of progress to date include the full installation and current pilot operation of the safety parameter display systems at Khmelnytskyy Unit 1, South Ukraine Unit 1, and Zaporizhzhya Unit 5. Ukraine's State Nuclear Regulatory Administration requires one full year of successful pilot operation before the systems can be declared fully operational.

In addition, the systems for Rivne Unit 3, Zaporizhzhya Unit 3, and South Ukraine Unit 2 have undergone successful factory acceptance testing at Westron facilities in Kharkiv. The Rivne Unit 3 system is completely installed at the plant and awaits plant permission/startup so final site acceptance testing can be performed. The system for Zaporizhzhya Unit 3 will undergo site acceptance testing and official turnover to the plant during January 2000. Pilot operation is scheduled to begin immediately afterward. The South Ukraine Unit 2 system is being installed at the plant. Installation initially was planned for completion in January, followed by site acceptance testing, turnover, and start of pilot operation. However, those activities are being delayed until March 2000 when South Ukraine Unit 2 is scheduled to restart after an extended shutdown.

In other action, committee members began work on the remaining system projects, ordering the long lead-time hardware for South Ukraine Unit 3 and Zaporizhzhya Units 2 and 4. These three systems are scheduled to be installed and turned over to those plants in mid- to late 2000. The current schedule also calls for installation of the final two systems during 2001 at Zaporizhzhya Units 1 and 6.

Based on the success of their efforts, steering committee members voted to rewrite their charter, transforming the committee into a working group, to meet only as needed until the remaining projects are completed. (Richard Reister, DOE, 301-903-0234; Rich Denning, PNNL, 614-424-7412; Frank Panisko, PNNL, 509-372-4472)

Ukrainian specialists participate in Kyiv seminar

In early December, U.S. specialists from Brookhaven National Laboratory presented a seminar in Kyiv on methodologies for quality assurance and peer review activities. Technical staff of Engineering Technologies and Developments (ET&D), the Ukrainian firm selected to provide those services for the in-depth safety assessment of South Ukraine NPP, hosted and conducted a majority of the seminar. Two specialists from the International Chornobyl Center in Slavutych also participated at the invitation of team members from DOE.

The U.S. presenters first described how to perform quality assurance audits of a probabilistic risk assessment project. Second, in the peer review portion of the seminar, they discussed the rationale and methods used to perform technical reviews of a probabilistic risk assessment project. The three days of presentations and accompanying discussions were held to support ET&D staff preparation of the peer review plan for reviewing the South Ukraine NPP probabilistic risk assessment. (Walter Pasedag, DOE, 301-903-3628; Ted Ginsberg, BNL, 516-344-2620)

Key analytical model work completed for Rivne safety assessment

In collaboration with staff of Rivne NPP, specialists from Energorisk (Rivne's Ukrainian subcontractor) completed work on two principal analytical models for use in the in-depth safety assessment of Rivne Units 1 and 2. The analytical models-also referred to as input data decks-are essential for completion of specific individual calculations that must be performed as part of the overall deterministic safety assessment for Rivne NPP.

In late November, Energorisk specialists finished modifying the RELAP5 basic thermal-hydraulic input data deck completed in October 1999. The modifications, including verification and validation of input data and models, will enable specialists to apply the RELAP5 model to the design-basis accident analyses of Rivne Unit 1.

In December, Energorisk specialists completed the MELCOR input data deck for Rivne Unit 1. The MELCOR deck provides the basic input data for analyses of the ability of Units 1 and 2 to mitigate consequences of accidents. This deck includes a detailed model of the bubbler condenser system, unique to the VVER-440 Model 312 reactor, for suppressing pressure and containing radioactive material in the event of an accident.

The design-basis accident analysis is an essential component of modern technology for assessing risks and identifying areas on which to focus resources for plant safety upgrades. The two models, completed in accordance with modern techniques for quality assurance and validation/verification, transfer the technology needed so Ukrainian team members can conduct the design-basis accident analyses for the Rivne in-depth safety assessment.

Also in December, Energorisk specialists finalized the definitions and category grouping of initiating events to be addressed in the Level 1 probabilistic risk assessment for Unit 1. This deliverable also provides an essential basic step for subsequent risk assessment work by the Ukrainian team. (Walter Pasedag, DOE, 301-903-3628; Charles Dickerman, ANL, 630-252-4622)

Ukrainian plant safety assessment projects reviewed

U.S. and Ukrainian participants reviewed progress and plans for two safety assessment projects under way at nuclear power plants in Ukraine. Meeting December 6 through 10 at Argonne National Laboratory in Argonne, Illinois, participants reviewed deliverables submitted as part of work on the design-basis accident analyses and Level 1 probabilistic risk assessments being done at Rivne and South Ukraine NPPs. Team members also prepared and agreed upon detailed schedules for completing those assessment tasks at both plants.

Meeting participants included Ukrainian and U.S. specialists involved in the in-depth safety assessments for the two plants. Two additional U.S. specialists joined the meeting for two days to review Ukrainian bounding mode analysis scenarios for analyzing the Rivne Unit 1 emergency operating instructions. (Walter Pasedag, DOE, 301-903-3628; Charles Dickerman, ANL, 630-252-4622; Christian Kot, ANL, 630-252-6151)