ML20008F922

Suppl to Final Deficiency Rept Re Suppression Pool Water Vol Contained in 801224 Ltr.Formal Documentation of Updated Pool Temp Transient Analysis Will Be Contained in May 1981 Chapter 6 of Design Assessment Rept

ML20008F922
Person / Time
Site:	LaSalle
Issue date:	05/04/1981
From:	Delgeorge L COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8105120335
Download: ML20008F922 (2)

Text

... - - . . -

. , ' . . 's [ C 's.)

Commonwealth Edison On, First Nati nal Ptaza Chicago, lilinois kO '? Addr;ss R;oly tr P:st Offica Box 767

( j/ Chic go. Illinois 60690 May 4, 1981 ,

,, Mr. James G. Keppler, Director  ! & '.9 Directorate of Inspection and Enforcement - Region III L

O% '*l4Pyl/pgb U.S. Nuclear Regulatory Commission 799 Roosevelt Road k k g %'eer J 6' /-

Glen Ellyn, IL 60137 --

,k,

Subject:

LaSalle County Station Units 1 and 2 Suppression Pool Water Volume Final Report - 10 CFR 50.55(e)'

NRC Docket Nos. 50-373/374-Reference (1): L. O. DelGeorge letter to J. G. Keppler dated December 24, 1980.

Dear Mr. Keppler:

The purpose of this letter is to supplement the information reported in Reference (1) relative to the LaSalle County Station suppression pool water volume. Subsequent to the submittal of the preliminary report made in Reference (1), the Final Safety Analysis Report was amended (Amendme'nt 54) to correct the documented pool volume to reflect the as-built situation. Reanalysis to verify the adequacy of the volume reduction (i.e., from 142,000 cubic feet originally reported to 128,000 cubic feet as-built) was not necessary inasmuch as the original analysis done to demonstrate adequate water volume to provide the required pressure suppression response was done assuming 117,000 cubic feet of water.

However, the initial analysis of long term pool cooling capability assumed 142,000 cubic feet of water. Therefore, a reanalysis was initiated at General Electric (GE) and a confirmatory analysis was begun by the architect engineer - Sargent & Lundy (S&L). These two analyses, which are now corplete, were performed using different computer codes; GE used the code Super HEX and S&L

, used their own proprietary code SUPTRAN. The solutions agree within l 4 percent and identified identical maximum pool temperatures for the l limiting case.

l The results indicate that for the Mark II Owner's White Paper Case 3, which is a scram with immediate isolation followed by ir.itiation of the RHR Heat Exchanger at the 10 minute point, the maximum temperature is 1870F. Other cases give results from 170 l

to 1770F using the as-built pool water volume. It has been shown that the 10 percent change in suppression pool water v0nume did not cause a marked difference in pool temperature response because the

! 30 8 s

l ()

l 8105120 W '

S

=

c 2-actual paol thermal capacity is sufficient to absorb the heat inputs prior to the time when the massive heat removal capacity of the RHR heat exchanger comes into effect. This confirmation of thermal adequacy of the as-built LSCS suppression pool water volume is sufficient justifiction to close this 10 CFR 50.55(e) report.

Formal documentation of the updated pool temperature transient analysis will be made in May, 1981 as part of Chapter 6 of the LaSalle County Station Design Assessment Report. However, as 4

was previously indicated, it is judged that this summary report of the analysis report for the most severe case to be analyzed is sufficient to close this issue. No further reporting under 10 CFR 50.55(e) on this issue will be made.

In the event you have any questions in this regard, please direct them to this office.

Very truly yours,

, a L. O. DeiGeorge f.

Nuclear Licensing Aoministrator 4

cc: Director of Inspection and Enforcement Washington, DC 20555+/' '

NRC Resident Inspector - LaSalle l

30358