ML18153C426

LER 90-011-00:on 901004,main Steam Safety Valves Out of Tolerance Due to Minor Setpoint drift.W/901102 Ltr

ML18153C426
Person / Time
Site:	Surry
Issue date:	11/02/1990
From:	Kansler M VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
90-687, LER-90-011, LER-90-11, NUDOCS 9011130086
Download: ML18153C426 (4)

Text

I.

Virginia Eiectric and Power Company Surry Power Station P. 0. Box 315 Surry, Virginia 23883 November 2, 1990 U. S. Nuclear Regulatory Commission Serial No.:.90-687 Document Control Desk Docket No.: 50-280.

Washington, D. C. 20555 License No.: DPR-32 Gentlemen:

Pursuant to Surry Power Station Technical. Specifications, Virginia Electric and Power Company hereby submits the following Licensee Event Report for Unit 1.

REPORT NUMBER 90-011-00 This report has been reviewed

• by the Station ,Nuclear Safety and Opera~ing Committee and will be reviewed by Corporate Nuclear Safety.

Very truly yours,

. Kansler

• Station Manager Enclosure.

cc: Regional Administrator Suite

• 2900 101 Marietta Street, NW Atlanta, Georgia 30323 90111300RA 90ttn~

roR* AD6tR b§bb6~80

~ _, PDC

NRC FORM 366

~6-89) -

e U.S. NUCLEAR REGULATORY COMMISSION APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92 ESTIMATED BURDEN PEA RESPONSE TO COMPLY.WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HAS. FORWARD LICENSEE EVENT REPORT (LERI COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) I PAGE 131 TITLE (41 Surrv Power Station. Unit 1 Io 1s 1010 (012181 o 1 loF 013 Main Steam Safety Valves Out of Tolerance Due to Minor Setpoint Drift EVENT DATE (51 LER NUMBER (61 REPORT DATE (7) OTHER FACILITIES INVOLVED (Bl MONTH DAY YEAR YEAR }it SE~~~~~~AL }? ~~i~~~ MONTH DAY YEAR FAC.ILJTY NAMES DOCKET NUMBER(SI 11 o oI 4 9 o 9 lo - o 11 I1 - ol o 1 I 1 oI 2 9 jo THIS REPORT IS SUBMITTED PURSUANT*TO THE Rl;QUIREMENTS OF 10 CFR §: (Check ona or mar* of tho following/ (111 N .

OPERATING I .

MODE (8) 20.402(b) 20.405(c) 60.73(1l12lliv) 73.71(b)

POWER 20.40511)11)1i) 60.31(cll11 60.73lill2lM 73.711c)

L~~~L Q I 5 16 ,_ 20.40511l11lllll 20.405(1)(1 )lill) X 50.31lcll21 50.7311)12)(i) -- 60.73(1)12)(vii)

&0.7311ll2llviilllA) e--

OTHER IStHCify in Ab1tn1ct bolow ond In Tut. NRC Form 366A}

20.405(1)11 )jlv) 20.405l1ll1lM II0.7311l12llill 60.7311)12,Ciii) -

LICENSEE CONTACT FOR THIS LER 112)

II0.7311l12llviiillB) 60.7311l12llx)

NAME TELEPHONE NUMBER AREA CODE M. R. Kansler, Station Manager 81014 315171-13111814 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 113)

~~60~;:gii 'iiiiii:iiiili!iiiiiiliiiiiiiiiiiiiliiiiiiiillliiiiii MANUFAC- MANUFAC*

CAUSE SYSTEM COMPONENT TURER TURER X S1 B RI V1 I y I I I I I I I I I I I I I I I I I I I I I SUPPLEMENTAL REPORT EXPECTED 1141 MONTH DAY YEAR EXPECTED n ~

SUBMISSION DATE (15).

YES /If y*s. comp/*t* EXPECTED SUBMISSION DATE/. NO I I I ABSTRACT /Limit to 1400 .,,.**,. i.*.. opproximotoly fiftosn 1in11l***P"** rypowritmn /ins1/ 116)

On October 4, 1990 and October 5, 1990, with Unit 1 at 56%

power during end of fuel cycle coast down, setpoint testing of the fifteen Main Steam Code Safety Valves revealed that the lift settings of four valves (SV-MS-lOlC, 102C, 104B, and 105B) were outside of the + 3% "as found" range allowed by Surry's Technical Specifications. Three of the valves exhibited lift settings ranging from 3.2%. to 3.5% below their nominal values.

The remaining valve exhibited a lift setting 3.7% above its nominal value. The safeties were readjusted as necessary to be within the* required setpoint tolerance. This event is reportable persuant to 10CFR50.73(a)(2)(i)(B) for conditions prohibited by Technical Specifications 3.6.A, 3.6.B.3 and 3.6.D.

NRC Form 366 16-89)

NRC FORM 366A (6-89)

LICENSEE EVENT REPORT (LERI e U.S. NUCLEAR REGULATORY COI\/IMISSION e APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-530). U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON. DC 20555, AND TO 1'HE PAPERWORK REDUCTION PROJECT (3150-01041, OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (21 LER NUMBER (61 PAGE (3)

Surry Power Station, Unit 1 0 I5 I O I O I O I 2 I 8 I O 9* IO - 0 I 111 - 0 I O O I 2 OF O I3 TEXT (ff more ,pace ill required, u"" Mlditional NRC Form 3fil!IA 'aJ (17)

1. 0 DESCRIPTION OF EVENT On October 4, 1990 and October 5, 1990, with Unit 1 at 56%.

power during end of fuel cycle coast down, setpoint testing of the fifteen Main Steam Code Safety Valves (EIIS-SB,RV) revealed that the lift settings of four valves (SV-MS-101.C, 102C, 104B, and 105B) (EIIS-SB,RV) were outside of' the + 3%

"as found". range allowed by Surry's Technical Specifications.

Three of the valves exhibited lift settings ranging from 3.2% to 3.5% below their nominal values. The remaining valve exhibited a lift setting 3. 7% above its nominal value. This event 1s reportable persuant to 10CFR50.73(a)(2)(i)(B) for conditions prohibited by Techriical Specifications 3.6.A, 3.6.B.3 and 3.6.D.

2. 0 SAFETY CONSEQUENCES AND IMPLICATIONS The Main Steam Code Safety Valves are provided to prevent overpressure conditions . in the secondary side of the steam generators and to ensure residual heat removal capability by relief of steam to atmosphere if the mam condenser and steam generator power operated relief valves are unavailable. An engineering evaluation was performed m 1986 following a similar event to determine the effects of high safety valve lift setpoints on the. accident analysis. The evaluation concluded that for the limiting overpressure event, (complete loss of load without reactor trip), peak reactor coolant system temperature and pressure would not be significantly affected, and the peak secondary side pressure would remain well within the design limits of. the secondary p1prng. Engineering has concluded based upon this evaluation, and accounting for current operating conditions, that the as found condition would not result in any safety limits being exceeded.* In addition, the low safety valve lift setpoints had no impact on the accident analysis. Because the safeties would have performed their safety* function, the health and safety of the public were not affected.

NRC Form 366A (6-89)

e NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB NO, 3150-0104 J. .,, .. EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) INFORMATION COLLECTION REQUEST: 50.0 HRS, FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) PAGE (3)

LER NUMBER (6)

SEQUENTIAL ;

;;;

;

* REVISION YEAR  :;::::::::: NUMBER  ::::::;:;: NUMBER Surry Power Station, Unit 1

• o 1s Io Io Io 1 21 s io 9.10 - 01 111 - o 10 oI 3 oF o 13 TEXT (If mom _,,,, ia requll'ff, u* Mldltional NRC Form 3ti6A 'aJ (17) 3.0 CAUSE OF THE EVENT The main steam safety valves experienced minor setpoint drift which can be expected under normal

• operating conditions.

Although the specific cause of this setpoint drift is not known, its occurrence is well documented 1Il the industry and is not considered to be abnormal.

4. 0 IMMEDIATE" CORRECTIVE ACTIONS The affected valves* were adjusted to within +/-. 1 % of the required setpoin ts.

5. 0 ADDITIONAL CORRECTIVE ACTIONS The valves were. tested three times to verify lift setpoints to be

• I within their required tolerance and based upon evaluations of the test data, it was determined that no additional testing or I maintenance was required.

6. 0 ACTIONS TAKEN TO PREVENT RECURRENCE None.

7.0 SIMILAR EVENTS Unit 1 LER 86-016-00, "B" Main Steam Safety Valve Setpoihts

8. 0 EOU°IPMENT MANUFACTURER/MODEL NUMBER Dresser 4". inlet, 6" outlet safety relief valve, Type 3767A-RT21 (SV-MS-IOlC)

Dresser 6" inlet, 10" outlet safety relief valve, Type 3707RA-RT21 (SV-MS-102C, 104B AND 105B)

NRC Form 366A (~9)