ML19344D936

Clarifies Work Items Which Have Had Input on Preliminary Risk Assessment Schedule.Suggests That Meeting Be Held on 800918 or 800824 to Present Interim Rept on Risk Assessment Program

ML19344D936
Person / Time
Site:	Limerick
Issue date:	08/20/1980
From:	Boyer V PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
NUDOCS 8008260392
Download: ML19344D936 (2)

Text

a e

PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 PHILADELPHIA. PA.19101 (2m 84 -450o

v. s. so v en SR. VICE PaES40ENT August 20, 1980 auc'raa rows a Docket Nos. 50-352 50-353 Mr. Darrell G. Eisenhut, Director U. S. Nuclear Regulatory Commission Division of Licensing Office of Nuclear Reactor Regulation Washington, DC 20555

Subject:

Preliminary Risk Assessment - Limerick Generating Station

References:

1)' V. S. Boyer letter to H. R. Denton, July 21, 1980

2) D. G. Eisenhut letter to E. G. Bauer, Jr., " Risk Evaluation - Limerick Generating Station, Units 1 and 2," May 6,1980

Dear Mr. Eisenhut:

As a result of the meeting held in Bethesda on July 11, 1980, to clarify the bases of the preliminary risk assessment of the Limerick Generating Station, the date of September 4,1980 was suggested as an appropriate time for a presen-tation of results (Reference 1). The purpose of this letter is to review the work items which have had an impact on the program schedule, and to document an i

informal agreement to delay the initial meeting to discuss the results of this effort.

Based on the scope of work involved to quantify the risk of the Limerick Generating Station, the 120 day period suggested in Reference 2 has been found to be inadequate for the following reasons:

The risk evaluation is the first to model the Mark II containment with the CONTEMPT / CORRAL computer code package to evaluate con-tainment failure modes and fission product release pathways. Signi-ficant modifications to standard CONTEMPT / CORRAL inputs have been j

l required to accommodate the Mark II design. Consequently, more time has been required than wc: id have been needed to evaluate a previously-I analyzed containment design.

g

,O y6 l

t 8008260392

a l

August 20, 1980 2

Mr. Darrell G. Eisenhut Because Limerick is still under construction, defining some final design and operational parameters for use in the analysis presents special problems. An example is the early specification of the inputs associated with operating procedures prior to the actual establishment of such procednes. This problem area is unique in relatica to previous detailad risk assessments which have been performed on operating plants. In the latter cases, input parameters are inherently easier to define.

Philadelphia Electric and its contractors are working diligently to perform the necessary evaluations on a timely schedule. While the fault trees and event trees are nearly complete, CONTEMPT evaluations and con-tainment analyses still require significant engineering effort. As informally discussed on August 13, 1980, we suggest the dates of either September 18 or September 24, 1980 for a meeting to present an interim report on the Limerick risk assessment program. At this meeting, we will provide a discussion of the risk assessment methodology employed and a detailed coverage of overall program status. A date for presentation of the final results of the preliminary risk assessment will also be able to be established at this time.

Sincerely, n

,