ML20196J690

Forwards Request for Addl Info Re GL 97-04, Assurance of Sufficient Net Positive Suction Head for Emergency Core Cooling & Containment Heat Removal Pumps

ML20196J690
Person / Time
Site:	Fort Calhoun
Issue date:	12/07/1998
From:	Wharton L NRC (Affiliation Not Assigned)
To:	Gambhir S OMAHA PUBLIC POWER DISTRICT
References
GL-97-04, GL-97-4, TAC-M99992, NUDOCS 9812100173
Download: ML20196J690 (3)

Text

. . -. .- - -- -- - . - . . - - - .

d l

1 . December 7,1998

. Mr. S. K. Gambhir Division Manager - Nuclear Operations Omaha Public Power District i Fort Calhoun Station FC-2-4 Adm.

Post Office Box 399 Hwy. 75 - North of Fort Calhoun Fort Calhoun, Nebraska 68023-0399 4

SUBJECT:

FORT CALHOUN STATION, UNIT NO.1 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO GL 97-04, " ASSURANCE OF SUFFICIENT NET 4

POSITIVE SUCTION HEAD FOR EMERGENCY CORE COOLING AND l CONTAINMENT HEAT REMOVAL PUMPS"(TAC NO. M99992) l

Dear Mr. Gambhir:

i j By letter dated October 29,1998, Omaha Public Power District (OPPD) submitted a 10 CFR i

50.59 safety evaluation of the 1992 Updated Safety Analysis Report (USAR) change for the ,

. Fort Calhoun Station that documented credit for subcooling in the calculation of net positive j

suction head (NPSH) for the containment spray and high pressure safety injection pumps.

l OPPD also submitted the calculation associated with the NPSH available for the containment  ;

spray and the high pressure safety injection pumps in the recirculation phase. On November  ;

i 16,1998, the staff discussed with OPPD questions regarding the submittals and the associated i staff review. Further discussion was conducted on December 2,1998, with OPPD and ABB-CE l I

to address staff questions.  !

The staff has determined that further information is needed to complete its review of the submittal. The information requested is listed in the enclosure. I Sincerely, ,

Or ,

p L.Raynard bginal Sgned Byar on, Proje0t y Project Directorate IV-2 ,

Division of Reactor Projects - Ill/IV  ;

Office of Nuclear Reactor Regulation t Docket No. 50-285 DISTRIBUTION:  !

Docket OGC .

Enclosure:

Request for Additional PUBLIC JKudrick j information PDIV-2 Reading KKavanagh  !

EAdensam (EGA1) RCaruso cc w/ encl: See next page WBateman RWharton  !

PGwynn, Region IV EPeyton l WJohnson, Region IV ACRS f l DOCUMENT NAME: FC99992.RAI g[O i j OFC PDIVf2/PM, PDIV-2/LA l NAME Rkh o E@ l DATE 121 7/98 12/ 1 /98 l OFFICIAL RECORD COPY 9812100173 981207 pDR ADOCK O g5 [h hg {go,_g ,

tgyg . ~.%f ,

l J

- - - - . .. - ...- -. . - - - ~.

l I

Mr. S. K. G:mbhir December 7, 1998 i

• 1 i

cc w/ encl: I Winston & Strawn ATTN: Perry D. Robinson, Esq.  !

1400 L Street, N.W.

5 Washington, DC 20005-3502 .

2 Mr. Jack Jensen, Chairman

Washington County Board  !

4 of Supervisors ,

l Blair, Nebraska 68008 l l Mr. Wayne Walker, Resident inspector  !

U.S. Nuclear Regulatory Commission Post Office Box 309 )

( Fort Calhoun, Nebraska 68023 i

i Regional Administrator, Region IV i

, U.S. Nuclear Regulatory Commission J 4

611 Ryan Plaza Drive, Suite 1000 i

Arlington, Texas 76011 i

Ms. Cheryl Rodgers, LLRW Program Manager Environmental Protection Section Nebraska Department of Health j l 301 Centennial Mall, South i

P.O. Box 95007 1 Lincoln, Nebraska 68509-5007

l l

Mr, J. M. Solymossy  !

l Manager - Fort Calhoun Station Omaha Public Power District -)

i Fort Calhoun Station FC-1-1 Plant 1

Post Office P ax 399

! Hwy. 75 - North of Fort Calhoun i Fort Calhoun, Nebraska 68023 Mr. Mark T. Frans l Manager- Nuclear Licensing ,

3 Omaha Public Power District l Fort Calhoun Station FC-2-4 Adm.

Post Office Box 399 Hwy. 75 - North of Fort Calhoun

Fort Calhoun, Nebraska 68023-0399 4

b

l 0

OMAHA PUBLIC POWER DISTRICI FORT CALHOUN STATION. UNIT NC.1 DOCKET NO.50-28L REQUEST FOR ADDITIONAL INFORMATION RELATED TO GENERIC LETTER 97-04

1. In calculation 0-MECH-CALC-021 Rev. 00, Appendix D, explain the difference between the CONTRANS analyses for cases AVOC and OSNVBV97.

2. Please confirm that only case OSNVBV97 is being used to calculate the subcooling available and explain why that is acceptable.

3. 0-MECH-CALC-021 Rev. 00 assumes that the height of the water in the sump is 6 feet based on Reference 3.11. However, page 4 of 25 of the current USAR Section 6.2 only assumes 2.8 feet of water. Explain why there is a difference in assumeo height of water

in the sump.

4. Explmn why the NPSH calculations are not time dependent or based on the temperature of be sump dunng your design basis accident.

5. The staff believes that you are referencing NRC SER dated April 11,1976, which reviewed CONTRANS Revision 1. Please confirm that the CONTRANS code used in the 1992 analysis is the same as the code accepted in 1976.

6. Have there been any modifications to the CONTRANS code since its acceptance by '.he NRC? Provide the current version number of the code that was used for this analysis.

If modifications have been made, provide the basis for the modifications to the code.

7. For the CONTRANS analysis, provide the inputs, assumptions, and bias that were used to ensure that the containrrent pressure was minimized.

8. According to calculation 0-MECH-CALC-021 Rev. 00, page D2, the pump manufacturer suggested that "any type of orifice or control valve is possible to alter the system curve to reduce the potential of run out flow. An orifice within the pump would also achieve simitar results by a steeper head /capa.ity curve causing less run out flow." Explain why this option was not chosen to resolve the run out flow issue.

9. Sir.ce the run out flow condition occurs during the recirculation phase, are there any procedures in place that instruct the operators to throttle the containment spray pumps in order to prevent the run out flow condition? If not, explain why this option was not considered feasible.