ML20203B468

Discusses Licensee 10CFR50.59 Evaluation of Leakage of Sump Water Into Refueling Water Storage Tank.Emergency Operating Procedure Encl.Licensee Usqe Acceptable

ML20203B468
Person / Time
Site:	South Texas
Issue date:	02/09/1998
From:	Alexion T NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
TAC-M99105, TAC-M99106, NUDOCS 9802240292
Download: ML20203B468 (16)

Text

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NOTE TO: PD IV 1 File Febru:ry 9, 1998 FROM: Tom Alexion ORIG SIGNED BY:

Project Directorate IV 1 Division of Reactor Projects lil/IV Office of Nuclear Reactor Regulation

SUBJECT:

LICENSEE'S 10 CFR 50.59 EVAltJATION OF LEAKAGE OF SUMP WATER INTO THE REFUELING WATER STORAGE TANK (RWST),

SOUTH TEXAS PROJECT, UNITS 1 AND 2 (TAC NOS. M99105 AND M99106)

By letter dated December 17,1996, the licensee provided its 10 CFR 50.59 Summary Report.

Based on my review of the Summary Report, Unreviewed Safety Question Evaluation (USQE) 96-0022, Revision 1, titled," Proposed Change Evaluates Doses From Leakage Of Sump Water into The RWST/ was selected for further review by the Office of Nuclear Reactor Regulation .

(NRR) technical staff. The reviewer was M. Shuaibi, Reactor Systems Branch, Division of l Systems Safety and Analysis.

This USQE was performed by the licensee to implement a change in design assumptions used to calculate radiological doses resulting from a loss of coolant accident (LOCA). Prior to this '

change, the licensee had accounted for leakage of sump water to the RWST from several sources including valve leakage past the containment spray manual test valves, the safety injection pump mini-flow recirculation valves and the RWST suction isolation valves. The change eddressed in the licensee's USOE credited stopping the containment spray pumps prior to ontainment spray leakage reaching the RWST. The licensee calculated the time for cnntainment spray water to reach the RWST to be 13.4 days. The licensee also calcmated the time for leakage from the other sources to reach the RWST to be 42.3 days. Therefore, asstming that the containment spray pumps are secured prior to 13.4 days allows the licensee to use the 42.3 days in their assessment of radiological doses.

i The Nuclear Regulatory Commission staff has completed its review of the USQE. The Emergency Operating Procodures (attached) state that "it may be necessary to run Containment Spray for up to 6.5 hrs [ hours) following a design basis LOCA in order to reduce Containment lodine levels low enough to support Control Room and TSC [ Technical Support Center) 30-day habitability." In addition, LOCA analyses show that the containment pressure reaches a maximum less than a minute into the accident and then starts decreasing. The containment pressure is reduced to less than 5 psig at 300 seconds. Therefore, the staff concludes that it is reasonable for the licensee to assume that the containment spray system will be secured prior to the 13.4 days. The staff further concludes that the licensee's USQE is acceptable.

Docket Nos. 50-498 and 50-499

Attachment:

As stated DISTRIBUTION: Docket File PUBLIC JTapia TAlexion Document Name: STP99105.NOT OFC PM/PO4 _t<k  ;

NAME TAlexion/vw DATE Ol k/98 COPY kEbG OFFICIAL RECORD COPY 9002240292 980209 PDR ADOCK 05000498 {

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UNITED STATES g

NUCLEAR REGULATORY COMMISSION WAsHINe1oN, D.C. EsseHeM

,,g, February 9, 1998 NOTE TO: PD IV 1 File FROM:

[hTomProjectAlexion Directorate IV.1 Division of Reactor Projects lil/IV C'1..< of Nuclear Reactor Regulation

SUBJECT:

LICENSEE'S 10 CFR 50.5g EVALUATION OF LEAKAGE OF SUMP WATER INTO THE REFUELING WATER STORAGE TANK (RWST),

l SOUTH TEXA8 PROJECT, UNITS 1 AND 2 (TAC NOs, Meg 105 AND Meg 106)

By letter dated December 17,1996, the licensee provided its 10 CM 50.5g Summary Report.

Based on my review of the Summary Report, Unroviewed Safety Question Evaluation (USQE) g6 0022, Revision 1, titled, " Proposed Change Evaluates Dosss From Leakage of Sump Water into The RWST,* was selected for further review by the Office of Nuclear Reactor Regulation (NRR) technical staff. The reviewer was M. Shuaibi, Reactor Systems Branch, Division of Systems Safety and Analysis.

This USQE was performed by the licensee to implement a change in design assumptions used to calculate radiological doses resulting from a loss of coolant accident (LOCA). Prior to this change, the licensee had accounted for leakage of sump water to the RWST from several sources including valve leakage past the containment spray manual test valves, the safety injection pump mini flow recirculation valves and the RWST suction isolation valves. The change addressed in the licensee's USQE credited stopping the containment spray pumps prior to containment spray leakage reaching the RWST. The licensee calculated the time for containment spray water to reach the RWST to be 13.4 days. The licensee also calculated the

. time for leakage from the other sources to reach the RW8T to be 42.3 days. Therefore, assuming that the containment apray pumps are secured prior to 13.4 days allows the licensee to use the 42.3 days in their asses nont of radiological doses.

Tne Nuclear Regulatory Commission staff has completed its review of the USQE. The Emergency Operating Procedures (attached) state that *it may be necessary to nan Containment Spray for up to 6.5 hrs [ hours) following a design basis LOCA in order to reduce Containment lodine leveis low enough to support Control Room and TSC [ Technical Support Center) 30 day habitabihty.' in addition, LOCA analyses show that the containment pressure reaches a maximum less tha a minute into the accident and then starts decreasing. The containment pressure is reduced to less than 5 psig at 300 seconds. Therefore, the staff concludes that it is reasonable for the licensee to assume that the containment spray system will be secured prior to the 13.4 days. The staff further concludes that the licensee's USQE is acceptable.

Ducket Nos. 50-498 and 50-499

Attachment:

As stated

DEC-30-1997 16:37 RJCLEAR LICENSING 512 972 8298 P.02/15

/

.50309e& 5 SOUTE TIEAS PROJECT ELECTRIC OENERATZMG STATION l

0P0F05 E0.E010 Rev. 7 LOSS OF REACTOR OR SECONDARY C00LMfT DEPARTMENT PROCEDURE SAFETY REIATED (Q)

Mk .,

. bl0ff) ** $*

UNIT OPERATION MANAGER DATE APPROVED DATE EFFECTIVE USAGE Colf!ROL: In Mand Controlling station Only e

LIST OF ATTACIMENTS:

o Addendum 1, Establishing Containment R2 Monitoring o Addendum 2, Establishing Alternate Charging Flow Control o Addendum 3, Emergency Electrical Loading Requ.irements o Addendum 4, sequencer Loading Verification - MODE III o Conditional Information Page This procedure is applicable in Modes 1, 2, and 3.

ATTACHMENT

DEC-30-19?? 16:37 NJCLEAR LICENSIK; 512 972 8299 P.03/15 l

OPOP05-EJ 2010 REV. 7 LOSS OF 4EACTOR OR SECONDARY COOLANT PAGE 12 OF 20 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED l

I M

It inny be necessary to run Contain= ant spray for up to 6.5 hrs following a design basis 1bCA in order to reduce Conrain= ant Iodine levels low enough to support Coctrol Room and TSC 30. day habitability. (Raf. Cale NC5013) 16 CIICE If Containment Spray should Be Stopped i~ a. Spray pumps . RUNNING a. GO TO Step 17.

,,,,,,,b. Containment pressure . LESS THAN b. PERFORM the following 6.5 PSIG

1) } GEN containmant pressure LESS THAN 6.5 PSIG, IHEE PERFORM Steps 16.c and 15 d.

2) CO TO Step 17 i

c. CONSULT TSC staff to determine if Containment Spray should be stopped.

_ d. _Wm,,t,N, permission is received f rom TSC raaff, Ilg2[ perform the following:

1) R2SE* containment spray signal

_ 2) PLACE Containment Spray System in Standby:

_ a) S7tP containment spray pumps and PLACE in AUTC g.g, _ b) CLOSE containment spray pump discharge valves

DEC-30-1997 16:37 NXLEAR L CENS Hr.i 512 972 8299 P.04/55 5050~90Mt 50075 TEEAS PROJECT ELECTRIC GENERATING STATIcef OPOP05-RO-ES11 Rev. 6 SI TERMINATION DEPARINENT PROCEDURE SAFETY RELATED (Q) 71%.D C//o/or (o - B % F-CNIT OPERATION MANAGER DATE APPROVID DATE EFFECTIVE USAGE CONTROLS 2 Eand Controlling Station only LIST OF ATTACRMENTS:

e o Addendum 1, Establishing Alternate Charging Flow Control o Addendum 2, Establishing Normal Letdown o Addendum 3, Establishing Excess Letdown o AAdanAum 4 Establishing Normal RCP Seal Cooling o Addandum 8, Emergency Electrical Loading Requirements o Addendum 6, Saturation Curve o Addendum 7, MCC Power Restoration o Addendum 8, Rer:etting ESF 5equencer Mode I Logic o Addendum 3, Sequencer Loading verification - Mode III o Conditional Information Page This procedure is applicab'.e in Modes 1, 2 and 3.

l l

DEC-30-1997 16:37 MJCLEAR LICENSING 512 972 8298 P.05/15

/

OPOP05-EC-1511 REV. 6 81 TERMINATION PAGE S OF 17 STEP ACTION /EX2SCTED RSSPCet*E RESPONSE NOT OSTAINED 15 TIE It may be necessary to run contaisument Spray for g to 6.8 bra following a design basis IACA in order to reduce Contaisument Iodina levels low enough to support Control Room and TSC 30. day habitability. (Ref. Calc NcS013) 10 CEECK If Containment Spray Should Be Stopped

,,_,,,a. Spray pumps . RUNNwG a 00 TO Step 11.

b. Contaira.nt pressure . LESS TRAN b. PERFOSM the ic11owing:

S.5 PSIG

1) ]EEE containment pressure LESS THAN S.S PSIG, 2EEE PERFORM

, Steps 10.c and 10.d.

2) GO To Step 11.

c. CONSULT TSC staff to determine if containment Spray should be

, stopped.

d. }fEEE permission is received from TSC staff. IEEE perform the following:

1) RESET containment spray signal-

2) PLACE Containment Spray System in Standby:

! a) STCt containment spray pumps and PLACE in A!TIO b) CLOSE containment spray pump discharge valves

_a

DEC-30-1997 16:37 bt) CLEAR LICENSING 512 972 8298 P.06/15 i

3c301096 SOU M TEIAS PRO.7ECT ELECTRIC SENERATING STATIcet CPOP05-30-EC21 Rev. 7 12tCOsrrROLLED DEPRESStntMATION OF ALL STEAM SENERATORS DEPARTMENT PAOCEDURE SAFETY RELkTED (Q)

?WMAdL o G/ tom ? (o - I 3 3~7-UNIT CPERATION MANAGER DATE APPROVED DATE EFFECTIVE USAGE CONTROL: In Mand Controlling Station Only LIST OF ATTACIDEENTS:

o A6dendum 1, Failing Air To MSIVs and MSIBs o Addendum 2, Resetting ISF Load Sequencer Mode I Logic o Addandum 3, MCC Power Restoration o Addendum 4, Establishing Alternate Charping Flow Control o Addendum 5, Establishing Normal Letdom2 o Addendum 6, Establishing Excess Letdown o Eddandum 7 Establishing Normal RCP Seal Cooling o Addendum 8, Emergency Electrical Loading Requirements o Addenaum 9. Saturation Curve o Addendum 10. Sequencer Lc,ading verification - Mode III o conditional Information Page This procedure is applicable in Modes 1, 2, 3 and 4.

DEC-30-1997 16837 N.JCLEAR LICENSING 512 972 8298 P.07/85

/ -

OPOP05-EO.EC21 EssWIZATIN OF M S M E'7 CENERATORS PAGE 12 0F 29 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT CSTAINED Ml2M 7t may be necessary to run Containment spray for g to s.5 hre following a design basis Inch in order to re&noe containment Iodine levels low enough to support Control moon and TSC 30. day habi+Ai14ty. (Ref. calc NOf013) 12 cuaCE If Containment spray should se stopped:

,,,, , a. spray pumps . RtnerING a. 00 70 Step 13.

b. Containment pressure . LESS TEAN b. PERPORM the foi.owing:

6.5 PSIG

1) EEE containment pressure tzss TEAN 5.5 PSIC, 2EEE PERFORM Steps 12.c ud 12.d.

2) 00 TO $tep 13.

c. CONSULT TSC staff to determine if Containment spray shoulst be stopped.

,,__ d. M[M permission is received from a

Tsc staff, IEEE perform .he following:

1) RESET containment spray signal

2) PIACE Contaimment Spray System in standby:

a) STOP containment spray

- pumps and PIACE in AUTO

,_,_ b) CLost containment spray  :

pump discharge val'*s I

IEC-30-1997 16:38 NLCLEAR LICENSlHG 512 972 8298 P.08/15 3o004MB SOUTE TIEA5 PROJECT ELECTRIC GENERATING STATION CPOP05-EO-EC31 Rev. 6 SGTR NITN LOSS OF REACTOR COOLANT - SUBCOOLRD RECOVERY DESIRED DEPARTMENT PROCEOURE SAFETY RELATED (Q)

"? y f. 8 0 fo '/O 9 Z N ' \S 'f, WIT OPERATf0N MANAGER DATF. APPROVT.D DATF RFFECTTVM USAGE CONTROL: In Hand controlling Station Only LIST OF ATTACHMENTS: '

I o Addendum 1, MCC Power Restorat' ion o Addendum 2, Resetting ESF Load Segeencer Mode I Logic o Addendum 3, Emergency Electrical Loading Reqviremants o Addendum 4, Establishing Alternate Charging Flow Control o Addendum 5, SG PORV Local Operation o Addendum 5, Containment Level vs. RWST Level o Addendum 7, Saturation Curve o Addendum 8, Secondary contamination Control o Addendum 3, Establishing Normal P.CP Seal Cooling o Addendum lo, sequencer Loading verification - MODE III o Addandum 11, Establishing Containment M2 Monitoring o Conditional Information Page This preacedure is applicable L- Modes 1, 2, and 3.

.b '

DEC-30-1997 16:30 NJCLEWR LICENGING 512 973 8299 P.09/a5 Oss OF REA N R @ N . M W W #8 OPOP05.EO-EC31 RECOVERY DESIRED PAGE E OF 30 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED Mm1 It may be necessary to run Contairumant Spray for up to s.S hrs following a design basis IDCA in order to reduce Containment Iodina levels low enough to support control Room and TSC 30. day habitability. (Ref. Calc ?:C6013) 11 CHECK If Containment Spray Should Se Stopped:

_ a. Spray pumps . RUNNING s. GO TO Step 12.

_ b. Containment pressure . LESS THAN b. PERFORM the following:

6.5 PSIG

1) }Q92! containtant pressure LESS THAN 6.5 PSIG,

• HEN PERFORM Steps 11.c and 11.d.

2) GO TO Step 12.

c. CONSULT TSC staff to determine if Containment Spray should be stopped.

d.1002i permission is received from TSC staff M perform the following:

_ 1) RESET containment spray signal

_ 2) PLACE Containment Spray System in Standby:

a) STOP containment spray pumps and PLACE ir AUTO b) CLOSE containment spray pump discharge valves

• ~

DEC-30-1997 16 30 H C.EMt LICENSING 512 972 6299 P.10/15

.'g s

.i 505ofA/9 SOUTE TEEAS PROJECT ELECTRIC GENERATING ETATION 0P0705 E0-E030 Rev. 8 STE&w ri m umTOR TUEE RUP1URE DEPARTMENT PROCEDURE SAFETY RELATED (Q) 6//e/f p 'O' b UNIT OPERATION MANAGER DATE APPROVED DATE EFFECTIVE USAGE CONTROL: In Band Controlling Station Only LIST OF ATTACHMENTS:

o Addendum 1, Failing Air To MSIVs and MSIts o Addandum 2, Main Steam Header Isolation o Addendum 3, Emergency Electrical Loading Rect.tirements o Addendues 4, SG PORV Local Operation o Addendum S, Establishing Alternate Charging Flow Control o Addendum 6, Establishing Normal Letdown o AAAanAun 7, Establishing Excess Letdown o Addendum S, Secondary contamination control o Addendum 9, Establishing Normal RCP Seal Cooling o Addendum 10, Saturation Curve o Addendum 11. MCC Power Restoration o Addendum 12, Resetting ESF Sequencer Mode I Logic o Addendum 13, Sequencer Loading Verification - MODE III o Conditional Information Page This procedure is applicable in Modes 1, 2, and 1.

DEC-30-1997 16*38 NJCLEAR L1 CENSING 512 972 8299 P.11/15

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OPOP05-RO E030 REv. 8 STEAM GENERATOR '!URE RUPWRE s

PAGE 28 CP 36 STEP ACTION /EXTECTED RESPONSE RESPONSE NOT OBTAINED EZII It may be necessary to run Contahat spray for up to 5.5 bre following a design basis LOCA in order to reduos Contata==at Iodine lewis low anough to support Coctrol Room and TSC 30. day babitability. (3ef. Cale WC6013) 28 CEECK If Containment spray should Be stopped:

a spray pumps . RUNFTNG a. GO TO Step 29.

b. Containment pressure . LESS THAN b. Pn FORM the following:

6.5 PSIG l

1) JEEt[ containment pressure LESS THAN 6.5 PSIG, IEEt[ PERTORM steps 28.c and 28.d.

2) 00 TO Step 29.

_ c. CONSULT TSC staff to determine if Containment spray should be st.;pped.

e

d. EHE2[ permission is received from TSC staff, Iggt! perform the following:

_ 1) RESET containment spray signal

_ 2) PLACE Containment Spray System in Standbya a) STOP containment spray pumps and PLACE in AITIO b) CLOSE containment spray pump discharge valves l

____a

DEC-30-1997 16:30 NUCLEAR LICENSING 512 972 8298 P.12/15

• STFECS UTSAR TABLE 6.2.1.1-10 ACCIDENT CHRONOIDCY F0ft DBA TACA l

Most severe Pump suction Break

{

nreak Type: Double-ended Cuillotina Break with Max SI. Min CHRS Time (Set:enda) ggggg 0 Break 16.5 Accumulator injection begins 21.0 Peak Containment pressure during blowdown 25.0 ECCS injection begins 38.0 seginning of fan cooler operation [

82.6 Beginning of Containment spray injection 82.6 Peak Containment pressure 137.0 End of core reflood 1.216.0 Beginning of recirculation 2,830.0 containment pressure reduces to 50 percent of peak value (gauge pressure) 4.008.4 End of steam generator energy release 1

6.2-79 Revision 5 a

DEC-30-1997 16 38 HUCLEAR LICENSING 512 972 8290 P.13e15 7

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SOUTH TEXAS PROJECT UNITS 1& 2 CONTAINMENT PRESSURE DECLG, CD 0.4 FIGURE t'5. 6-13 RtvlstoN 5 g team J

DEC-38-1997 16:38 MJCLEWt LICENSING 512 972 8298 P.14/85 4

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SOUTH TEXAS PROJECT UNITS 1 h 2 CONTAINMENT PRESSURE DECLG, CD 0.6 F10URE 15. 5-19 REV1SION 5 h

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4 . DEC-39-1997 16:39 NJCLEAR LICENSING 512 972 8298 P.19/15

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$10 ,

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SOUTH TEXAS PROJECT UNITS 1& 2 CONTAINMENT PRESSURE DECLG,'CD = 0.8

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acvisicw s Q Lests.est TOTAL P.15

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