ML20238B481

Requests Permision to Convert Plant Model,Originally Developed for Trac Code Under PTS Program,To RELAP5 Code for Use in Safety Performance Improvement Program.Current Emergency Operating Procedures Requested.Telcon Record Encl

ML20238B481
Person / Time
Site:	Calvert Cliffs
Issue date:	12/31/1986
From:	Solberg D NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
To:	Mirsky S BALTIMORE GAS & ELECTRIC CO.
Shared Package
ML20237F598	List: IA-87-388, Forwards B&W Assessment Program Rept, for 870316-0401 ML20237F594 ML20237F631 ML20237F670 ML20238B253 ML20238B343 ML20238B414 ML20238B445 ML20238B481 ML20238B501 ML20238B545 ML20238B572 ML20238B608 ML20238B616 ML20238B626 ML20238B640 ML20238B657
References
FOIA-87-388 NUDOCS 8709010239
Download: ML20238B481 (3)

Text

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• U S I DEC ssr Mr. Steven Mirsky 1 Baltimore Gas and Electric Co.

P. O. Box 1535 .

Lusby, MD 20657 ,

Dear Mr. Mirsky:

In a recent telephone conversation I requested BG&E approval to use a model of the Calvert Cliffs plant orginally developed for the TRAC code under the pressurized thermal shock program. We propose. to convert the model to the RELAPS code for use on another program being perfonned for us by EG&G Idaho which I will explain below. Per your recommendation this letter is fonnally -1 rcquesting this alternate use of the Calvert Cliffs model. I As you are perhaps aware, NRC is involved in a safety reassement of B&W-design 1 plants. The B&W Owners Group (BWOG) agreed .to take the lead on this effort with a program they refer to as " Safety Performance Improvement Program." As part' of the independent NRC review of the BWOG program, we have undertaken research which will provide us with a ccx9arison of the demands that three types of transients make on the safety systems and operators for representative plants a of each PWR vendor using the same computer code, RELAP5. Since these plants are supposed to be representative of the design of each vendor, we expect to publish the results withoilt referring to the specific plant modeleo. One RELAP5' iriput deck will model the Calvert Cliff plant to provide us with the basic thennal/ hydraulic response of the plant. We will_ also generate critical safety fonction response trees for each plant as well as time-based operational sequence diagrams for each transient analyzed. I am enclosing our proposed work l plan for this project which describes these concepts in more detail. From ,

these data we will determine the relative reliance on system capabilities and  !

cperator performance at each plant. Factors to be evaluated are:

(1) redundancy and diversity' of systems and equipment that support the safety functions;- , .

(2) diversity of operator actions and decisions tiat are made for restoring control for each of the transients; fnd ,

(3) relative time available for operator action, diagnosis and error recovery for each of the tran.ients.

For any major differences observed among the plants we would also propose to examine:

(1) the major reasons for the differences, eg, due to design, operations or other causes; '

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. 2 (2) if they are adequately modeled in the plant PPA; and (3) if the differences are risk significant.

Our modeling of all aspects of the three vendor plant responses will improve as we include more plant-specific data. The thermal / hydraulic models will provide basic response characteristics and timing. Our ability to construct and i evaluate critical response trees and operational sequence diagrams would be improved if we had a current e;nergency operating procedure (E0P) for each plant and could discuss plant operations with members of the operating staff.

Therefore, we request that you consider providing our contractor, INEL, with a current E0P and provide them with limited access to plant operating staff in order to insure an adequate understanding of plant procedures. In exchange for this assistance, we would be willing to supply you with the RELAPS model, critical safety function re.sponse trees, operational sequence diagrams and other information developed by the program for the Calvert Cliffs plant.

The initial phase of our program is scheduled to be completed in April 1987.

Although we have no plans for a follow-on effort, it is possible that the i models we have developed could be used by NRR to:

(1) ev61uate response characteristics for variations on the three transients selected or for other transients for all three plants (2) evaluate the effect of BWOG-recommended changes to the design and operation of B&W-designed plants on the inter-plant comparisons.

Your timely response to our request would be appreciated. If you or the Calvert Cliffs plant staff have further questions concerning this request, please feel free to contact me at (301) 443-7695.

Sincerely, Donald Solberg Reactor Systems Franch Division of Reactor System Safety, RES

Enclosure:

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