ML20023E079

LER 83-007/03L-0:on 830429,PORV RC-455C Failed to Meet Required Cycle Time & Failed to Open Fully on Subsequent Attempt.Caused by Galling of Valve Plug to Cage Due to Rubbing of Stainless Steel in Dry condition.W/830527 Ltr

ML20023E079
Person / Time
Site:	Robinson
Issue date:	05/27/1983
From:	Cox H, Starkey R CAROLINA POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
LER-83-007-03L-02, LER-83-7-3L-2, RSEP-83-675, NUDOCS 8306070182
Download: ML20023E079 (4)

Text

NRC FORM 366 U. S. NUCLE AR HEGULATORY COMMISSION 17 77) ,

,' . LICENSEE EVENT REPORT CONTROL BLOCK: l l l l l l l (PLE ASE PRINT OR TYPE ALL REQUIRED INFORMATION)

• 1 6 7

0 1 8 9 lSlC l H l B l R l142 l@l LICENSEE CODE IS 0 l 0 l- l 0LICENSEl0l0 l 0 l 0 l- l0 l 0 25l@l264 l 1LICENSE NUMBER l 1 l 1TYPEl 1JOl@l b 7 CAl T $8l@

CORfT lol11 Zn"C l60L l@l61015 l 0DOCKET l 010 l 2 l 611 68l@l69014 EVENT l 2 l9OATE l R 13 l@l 7501 SREPORT 14 l 2 l DATE 7 l 8 l 380 l@

7 8 NUMBER EVENT DESCRIPTICN AND PROBABLE CONSEQUENCES h

, I o l 2 l 10n April 29. 1983, at 2153 hours0.0249 days <br />0.598 hours <br />0.00356 weeks <br />8.192165e-4 months <br />. with the unit at 0% power. during testing of the l g o i3; l Pressurizer Power Operated Relief Valves (PORV), valve RC-455C failed to meet the l g o [4 ] ] required cycle time and on a subsequent attempt failed to open fully. This event l o s l resulted in operation in a degraded mode permitted by a limiting condition for l

[O is l l operation as defined by Technical Specification 3.1.2.1.d and is reported pursuant I o 7 l to 6.9.2.b .2. The redundant PORV was operable and the unit achieved cold, depressur- l ized conditions at 1545 hours0.0179 days <br />0.429 hours <br />0.00255 weeks <br />5.878725e-4 months <br /> on April 30, 1983. Therefore, there was no threat to j o ls l l the public health and safety. I C E CODE SUBCO E COMPONENT CODE SU8C DE SU E ITTil I S I H l@ [Ej@ l_Bj @ I v l A l L l V l E l X lh Wh [B_) h B 20 7 8 4 10 11 12 13 18 19 SEQUENTIAL OCCURRENCE REPORT REVis:ON LER RO kVENT YEAR REPORT NO. CODE TYPE NO.

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[_j 23 l 010171 24 26 d

27 10131 28 N M30 l-l 31 101 32 TAKEN AC ON ON PL NT MET HOURS SB IT FOR b B. SUPPLIE R MANUF CTURER b_J@L21@ L7J@ L7J@ l01010101 LIJ@

41 LaJ@ LaJ@ lCl6I3Isl@ 47 33 J4 35 36 3/ 40 42 43 44 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h l i l 0 l l Inspection of RC-455C revealed the cause of failure to be galling of the valve plug tol i i [ cage and is attributed to the rubbing of similar grades of stainless steel materials I

, ., lagainst each other in a " dry" condition. This " dry" condition is normal for the l m l gas space of the Pressurizer and the PORVs. The valve was rebuilt with new com- l ponents and returned to service on May 12, 1983, during the current Steam Generator Ii141 10utage. 1 7 8 g 80 STA S  % POWER OTHER STATUS dis O RY DISCOVERY DESCRIPTION i 1 5 (_jh l0l0l0l@l N/A l [_jhl Operator Obeervation l ACTIVITY CO TENT RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE 1 6 [Z_] h LZ_j @ l N/A l l N/A l J B 9 10 11 44 45 80 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION i 7 l0 l 0 l0 l@[Z_jhl N/A l PERSONNE L INJURIES NUMBER DESCRIPTION

[TIIIl8'9l0 l 0 l0 lhl 7 11 12 N/A 80 l

LOSS OF OR DAMAGE TO FACILITY Q TYPE DESCRIPTION v Q (Z_j h l 10 N/A l 60 7 8 9 PUsuCITY DESCRIPTION 8306070182 830527 NRC USE ONLY

• ISSUED PDR ADOCK 05000261 2 o [N_jhl S PDR I 68 69 I I I I I I I I I I I I !I ^

7 8 9 10 NAME OF PREPARER Howard T. Cox PHONE: (803) 383-4524 Ig

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- Cp&L ,s %+a Carolina Power & Light Company 0 >,0

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.. . 9 H. B. ROBINSON STEAM ELECTRIC PLANT $ #

Post Office Box 790 P

3k Hartsville, South Carolina 29550 "f p 03 MAY 2 71983

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Robinson File No: 13510C Serial: RSEP/83-675 Mr. James P. O'Reilly Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261 LICENSE NO. DPR-23 LICENSEE EVENT REPORT 83-007 _._

Dear Mr. O'Reilly:

In accordance with Section 6.9.2 of the Technical Specifications for the H. B. Robinson Steam Electric Plant, Unit 2, the enclosed Licensee Event Report is submitted. This report fulfills the requirements for a written report within thirty (30) days of a reportable occurrence and is in accordance with the format set forth in NUREG-0161, July,1977.

Very truly yours, k l' R. B. Starkey, Jr.

General Manager H. B. Robinson SEG Plant HTC:FMG:JMC:CWC/th Enclosure cc: R. C. DeYoung (30)

R. A. Hartfield (3)

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' OFFICIAL COPY

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SUPPLEMENTAL INFORMATION FOR LER 007 I. Cause Description and Analysis On April 29,1983, at 2153 hours0.0249 days <br />0.598 hours <br />0.00356 weeks <br />8.192165e-4 months <br />, with the unit at 0% power, during testing of the Pressurizer Power Operated Relief Valves (PORV), valve RC-455C failed to meet the required cycle time. The valve was sub-sequently retested with similar results and on a third test would not fully open. RC-455C was declared inoperable at 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br /> on April 29, 1983.

Disassembly and inspection of the valve revealed that the valve internals had experienced galling which caused the valve plug to bind on the cage. This galling is attributed to the valve internals being made of similar grades of stainless steel materials and rubbing against each other in " dry" conditions. This " dry" condition is normal for the PORV which relieves the gas space of the pressurizer.

Also, a minor valve operator diaphragm leak was discovered but is not believed to have contributed to the slow cycle times.

This event resulted in operation in a degraded mode permitted by a limiting condition for operation as defined by Technical Specification 3.1.2.1.d and is reported pursuant to 6.9.2.b.2. The redundant PORV was operable during this event and the unit achieved cold shutdown conditions and was depressurized at 1545 hours0.0179 days <br />0.429 hours <br />0.00255 weeks <br />5.878725e-4 months <br /> on April 30, 1983. Therefore, there was no threat to the public health and safety.

II. Corrective Action RC-455C was disassembled and all damaged components were replaced with new parts from stock. Special attention was directed to cleanliness during valve reassembly to preclude introduction of any debris into the valve plug / cage area. This was done in an effort to reduce the potential for developing a gall. The cause of valve failure is at-tributed to dry operation of the PORV. RC-455C was returned to service on May 12, 1983, during the current Steam Generator Outage.

The redundant PORV was also disassembled and inspected. No galling of the valve internals was observed; however, due to minor seating i cuts from normal operational wear, the valve internals were renewed.

I

Pagn 2 III. Corrective Action to Prevent Recurrence An engineering review has been initiated to investigate the appropriateness of the materials used for the PORV internals and to determine if an improvement can be made to prevent the observed galling. Any corrective actions deemed necessary as a result of this review will be implemented and provided as a supplement to this report. The results of the engineering review will also be used to determine the reportability of this event under 10CFR21.

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