ML18100A335

Provides Clarification of Reduced Safety Injection Evaluations.Informs That Min SI Flow Rates Assumed in Evaluation Documented in Ref Ltr Are Bounded by Those Previously Evaluated

ML18100A335
Person / Time
Site:	Salem
Issue date:	12/18/1992
From:	Huckabee J WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:	Ranalli J Public Service Enterprise Group
References
ET-NSL-OPL-II, NUDOCS 9305070245
Download: ML18100A335 (3)

Text

• • PSE-92-228

• Westinghouse Electric Corporation Energy Systems Box 355 Pittsburgh Pennsylvania 15230-0355 Mr. Jerome A. Ranalli, Manager December 18, 1992 Nuclear Fuel ET-NSL-OPL-II-92-593 Public Service Electric & Gas Company P.O. Box 236 Mail Code N50 Hancocks Bridge, NJ 08038 I . Public Service Electric & Gas Company Salem Units 1 and 2 Clarification of Reduced Safety Injection Evaluations

Reference:

1) PSE-91-038, dated February 28, 1992

Dear Mr. Ranalli:

The referenced letter provided a safety evaluation supporting a change to the requirements in the Salem Units 1 and 2 Technical Specifications for ECCS (Emergency Core Cooling System) pump performance. Section 3 .1.1 of that evaluation contains the statement, "The result of this evaluation shows that the minimum safety injection flows assumed in previous SI reduction evaluations are more conservative for RCS pressures greater than 875 psia." Per a PSE&G request, the following provides clarification of this statement.

Since April of 1990, there have been a number of Salem evaluations performed for redu~ions in minimum Safety Injection (SI) flows. The affected transients include Steamline Break Mass and Energy Outside Containment (SLB M&E OC) performed for equipment qualification, Steamline Break Mass and Energy Inside Containment (SLB M&E IC) performed for determination of the containment pressure and temperature response, and Steamline Break Core Response (SLB CR) performed to determine the margin to DNB (Departure-from Nucleate Boiling).

In May of 1990, Westinghouse evaluated the Salem Unit 1 licensing basis analyses for a reduction in safety injection flow. Those minimum SI flows are shown as Case 1 in the attached Table 1. That evaluation concluded that past operation of Salem Unit 1 with degraded Charging/SI pumps was supported by the licensing basis non-LOCA analyses. Later in May of 1990, it was determined that the pump data supplied to Westinghouse should have been based on an orifice reduction factor, K, of 19 .4 instead of 17. 7. Since the impact of this change is to raise the calculated SI flow, no evaluation of increa8ed minimum SI flow was required ..

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• • Mr. J. A. Ranalli Page 2 December 18, 1992

• In August of 1990, an evaluation was performed to support startup and continued operation of Salem Unit 2 with revised ECCS performance. In October of 1990, an evaluation was performed which determined that past operation of Salem Unit 2 with degraded Charging/SI pumps was supported by the licen5ing basis analyses. Those minimum SI flows are shown as Case 2 in the attached Table 1.

This evaluation assumed the most limiting SI flow rates available at that time and concluded .that since those SI flow rates were less than 1% below the flow rates assumed in the May and September 1990 evaluations performed for Salem Unit 1, the previous evaluation results and conclusions remained valid.

The most recent evaluation was performed in February of 1991 to evaluate the newest SI flows for both Salem units in support of wider Tech Spec ECCS surveillance test ranges for the Charging/SI pumps. Those minimum SI flows are shown as Case 3 in the attached Table 1. With respect to minimum SI flows for Steamline Break analyses, the newest SI flow rates are bounded by the flow rates assumed in the previous evaluations mentioned above for pressures greater than 875 psia.

Therefore, SLB analyses results which do not go below 875 psia will remain bounding with respect to minimum SI flows.

The limiting SLB M&E OC analysis case does not go below 890 psia.. Therefore, the SI flow rates .*

assumed in the evaluations performed previously, which concluded that the licensing-basis analyses support Salem Unit 1 and 2 operation with degraded Charging/SI pumps, bound (are more limiting than) the newest SI flow rates .

• For SLB CR, while the transient results in pressures below 875 psia, it was determined that there is a negligible change to* the heat flux, pressure, and core boron concentration from what was previously evaluated and.found to be acceptable. Therefore, it was concluded that the licensing-basis statepoints are unchanged and the Tech Spec relaxation would*have no impact on the SLB CR analysis results.

The SLB M&E IC case which was limiting with respect to minimum RCS pressure was a split break which reached a minimum pressure above 875 psia. In addition, the peak containment temperatures result from small breaks at 102 % power and none of these cases reached pressures below 875 psia.

Therefore, the licensing basis cases bound the newest SI flows for SLB M&E IC.

In summary, it was determined that the minimum SI fl.ow rates assumed in the evaluation documented

• in the referenced letter are bounded by those previously evaluated.

If there are any questions,_ please contact the under:signed.

AMS/lg

• cc: T. K. Ross R. S. Kent J. A. Rowey H. G. Berrick

CASE 1 - MAY 1990, SALEM UNIT 1 JUSTIFICATION FOR PAST OPERATION CASE 2 - OCTOBER 1990, SALEM UNIT 2 JUSTIFICATION FOR PAST OPERATION CASE 3 - FEBRUARY 1991, SALEM UNITS l AND 2 SI TECH SPEC EVALUATION To a.co:ommodll!c the LOFTRAN code, only ten of the ECCS flow vs. prc:.ssure valuei; etre act1.14lly input into ~ la:lll.ly.wa;. Tho Table I Ca.~ 3 vllluc:s ~¢m.: lart;cr than the Cuo !12 values at &ix'lllt 1325 psig. Ho~cver, the analyses do not a.s:rumc ECCS flow vs. pruaure values betw~tl 1325 smd 875 psig, Therefore, with tci;pcct to the analyai:i inpu~ ~which the F"bl'Wll)' 1991 cv&.!u..tion is b11.~. the ECCS t1ov.* iii unaffected until 87S p~ig.

It is con.~rvativ" w assume the evtJWIIion is affe.:t.:d iu the higher pres~re, since the cvcnta ana.lyud would be impacted as soon as th.: rcsul~ docrea.~ bolo.,., th.a! pres.9ure. Thc:refott, ECCS values ~tween 875 pjig and 1325 p$i~ wt.re evaluated. Tiw evrJuation CQOC!udod that, ~in.:<> the ma.x.i.mum di.f!cren~ ~ween Case l/:Z Mid 3 (which OC¢Un> ar a.bout 900 ptiig) wu !"~:;; tlWl 5 3, the diffe.ret'I¢< was oon.siderod i.n:;ignificant with rospcct to impact on the pr"vioui; una.ly!!4s/cvaluations.