ML17290B200
| ML17290B200 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 05/26/1994 |
| From: | Hugo B WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| To: | NRC |
| References | |
| REF-PT21-94 NUDOCS 9406060198 | |
| Download: ML17290B200 (6) | |
Text
ACCELERAT+ DOCUMENT DISTRUTION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RXDS)
ACCESSION NBR:9406060198 DOC.DATE: 94/05/26 NOTARXZED:
NO FACXL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe AUTH.NAME AUTHOR AFFILIATION HUGO,B.
Washington Public Power Supply System RECIP.NAME RECIPXENT AFFILXATION NRC No Detailed AffiliationGiven DOCKET 05000397
SUBJECT:
Part 21 rept re Automatic Switch Co replacement solenoid pilot valve diaphragms supplied by GE Nuclear Energy. Unusual combination of scram soleniod pilot valve pressure 6 exhaust diaphragm degradation caused failure of rod to scram.
DXSTRIBUTION CODE IE19D COPIES RECEIVED:LTR ENCL SIZE TITLE: Part 21 Rept (50 DKT)
NOTES:
D RECIPIENT ID CODE/NAME PDIV-3 PD INTERNAL: AEOD/~
~REPTILE 01
~RGN1-RGN3 RGN5 EXTERNAL: INPO RECORD CTR NSIC SILVERg E
, COPIES LTTR ENCL 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
RECIPIENT ID CODE/NAME CLIFFORD",J NRR/DRIL/RVIB RES/DSIR/EXB RGN2 RGN4
- SECY/PDR NRC PDR COPIES LTTR ENCL 1
1 1'
1 1
1 1
1 1
1 1
1 1
D D
D D
NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEEDl TOTAL NUMBER OF COPIES REQUIRED:
LTTR 15 ENCL 15 D
~ MY-26-1994 12: 58 589 377 4317 P.8&82 Docket No. 50-397 U.S. Nuclear Regulatory Commission May 26, 1994
Subject:
WNP-2, OPERATING LICENSE NPF-21 10 CFR PART 21 RfH'ORT AUTOMATICSW1TCH COMPANY (ASCO) REPLACFMENT SOLENOID PILOT VALVEDIAPHRAGMS SUPPLIED BY GENERAL ELECTRIC NUCLEARENERGY This is an initial 10 CFR Part 21 notification to the NRC Operations Center.
A written report willbe submitted as a revision to an existing WNP.-.2;Licensee Event Report (LER 94-005).
Supplier:
General Electric (GE) Nuclear Energy 175 Curtner Avenue San Jose, CA 95125 Scram solenoid pilot valve (SSPV) diaphragms supplied to WNP-2 by GB Nuclear Energy have shown a decreased service life compared with previous experience.
Diaphragms removed from service following the March 26, 1994, failure of a control rod to scram had significant degradation consisting of hardening, set, and cracking.
This degradation has resulted in increased. scram time for some control rods.
An unusual combination of SSPV pressure and exhaust diaphragm degradation caused the failure of one control rod to scram.
Diaphragms with significant degradation had been in service between 3.6 and 4 years.
The supplier recommends a maximum 4 year service life. Analysis of the diaphragms indicates a difference in the composition of the Buna-N material (e.g., variability in filler, acrylonitrile, and plasticizer content) compared with diaphragms removed in 1990.
This composition difference may have changed the aging characteristics of the Buna-N material; diaphragms removed in 1990 had less degradation after up to 6.6 years in service than those removed in 1994 with up to 4 years in service.
The Washington Public Power Supply System does'not believe that diaphragm shelf life was a factor in this degradation.
The SSPV diaphragms have been replaced for all control rods.
WNF-2 is reevaluating the allowable service life of the diaphragms.
Should you have any questions or desire additional information, please call Bruce R. Hugo at (509) 377-8593.
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POWER REACTOR EVENT NUMBER:
27305 FACILITY: WASHXNGTON NUCLEAR UNIT:
[2]
[ ]
[
]
RX TYPE:
[2] GE-5 NRC NOTIFIED BY: BRUCE R.
HUGO HQ OPS OFFICER:
STEVE SANDIN REGION:
4 STATE:
WA NOTIFICATION DATE: 05/26/94 NOTIFICATION TIME-16:00
[ET]
EVENT DATE:
05/26/94 EVENT TIME:
00:00[PDT]
LAST UPDATE DATE:
05/26/94 NOTIFICATIONS UNSPECIFIED PARAGRAPH EMERGENCY CLASS:
NOT APPLICABLE 10 CFR SECTION:
CCCC 21.21 UNIT SCRAM CODE RX CRIT INIT PWR INIT RX MODE 0
REFUELING CURR PWR CURR RX MODE 0
REFUELING EVENT TEXT LICENSEE IS MAKING A PART 21 NOTIFICATION.
SUBJECT:
WNP-2, OPERATING LICENSE NPF-21 10 CFR PART 21 REPORT AUTOMATIC SWITCH COMPANY (ASCO)
REPLACEMENT SOLENOID PILOT VALVE DIAPHRAGMS SUPPLIED BY GENERAL ELECTRIC NUCLEAR ENERGY SUPPLIER:
NUCLEAR ENERGY 175 CURTNER AVENUE SAN JOSE, CA 95125 SCRAM SOLENOID PILOT VALVE ( S S PV)
DIAPHRAGMS SUP PL IED TO WNP - 2 BY GE NUCLEAR ENERGY HAVE SHOWN A DECREASED SERVICE LIFE COMPARED WITH PREVIOUS EXPERIENCE.
DIAPHRAGMS REMOVED FROM SERVICE FOLLOWING THE MARCH 26,
- 1994, FAILURE OF A CONTROL ROD TO SCRAM HAD SIGNIFICANT DEGRADATION CONS'ISTINQ OF HARDENING, SET, AND CRACKING. THIS DEGRADATION HAS RESULTED IN INCREASED SCRAM TIME FROM SOME CONTROL RODS.
AN UNUSUAL COMBINATION OF SSPV PRESSURE AND EXHAUST DIAPHRAGM DEGRADATION CAUSED THE FAILURE OF ONE CONTROL ROD TO SCRAM n
"DIAPHRAGMS WITH SIGNIFICANT DEGRADATION HAD BEEN IN SERVICE BETWEEN 3.6 AND 4 YEARS.
THE SUPPLIER RECOMMENDS A MAXIMUM4 YEAR SERVICE LIFE.
ANALYSIS OF THE DIAPHRAGMS INDICATES A DIFFERENCE IN THE COMPOSITION OF THE BUNA-N MATERIAL (e.g.,
VARIABILITYIN FILLER, ACRYLONITRILE, AND PLASTICIZER CONTENT)
COMPARED WITH DIAPHRAGMS REMOVED IN 1990.
THIS COMPOSXTION DIFFERENCE MAY HAVE CHANGED THE AGING CHARACTERISTICS OF THE BUNA-N MATERIAL; DIAPHRAGMS REMOVED IN 1990 HAD LESS DEGRADATION AFTER UP TO 6.6 YEARS IN SERVICE THAN THOSE REMOVED IN 1994 WITH UP TO 4 YEARS IN (Continued on next page)
FACILITY: WASHINGTON NUCLEAR PAGE g 2
OF EVENT NUMBER: 27305 SERVICE.
THE WASHINGTON PUBLIC POWER SUPPLY SYSTEM DOES NOT BELIEVE THAT DIAPHRAGM SHELF LIFE WAS A FACTOR IN THE DEGRADATION."
"THE SSPV DIAPHRAGMS HAVE BEEN REPLACED FOR ALL CONTROL RODS.
WNP-2 IS REEVALUATING THE ALLOWABLE SERVICE LIFE OF THE DIAPHRAGMS."
THE LICENSEE WILL PROVIDE A WRITTEN REPORT AS A REVISION TO AN EXISTING WNP-2 LICENSEE EVENT REPORT (LER 94-005).
. '.it%Y-26-1994 12: SS
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