ML19347C700
| ML19347C700 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 12/19/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Parris H TENNESSEE VALLEY AUTHORITY |
| References | |
| NUDOCS 8101050153 | |
| Download: ML19347C700 (2) | |
Text
,
.t N
Scotc,
o 4
UNITED STATES o
o
'g 8"
NUCLEAR REGULATORY COMMISSION s,
g a z REGION 11 g
l[
101 MARIETTA ST,, N.W.. SUITE 3100 o,
ATLANTA, GEORGIA 30303 rg
{
o' g.
g N'
J-3 In Reply Refer To:
j
^
,.y RI,I.;JPO
~x
,j 3
0-259, 50-260 ij
- 5
.50-796
~ )
M 3
c
~
ja
=
w rn R*
Tennessee Valley Authority
'p ATTN:
H. G. Parris Manager of Power 500A Chestnut Street Tower II Chattanooga, TN 37401 Gentlemen:
The enclosed IE Bulletin No. 80-25, is forwarded for action. A written response is required.
In order to assist the NRC in evaluating the value/ impact of each bulletin on licensees, it would be helpful-if you would provide an estimate of the man-power expended in conduct of the review and preparation of the report (s) required by the bulletin.
Please estimate separately the manpower associated with corrective actions necessary following identification of problems through the bulletin.
If you desire additional information regarding this matter, please contact this office.
Sincerely, l
l James P. O'Reilly Director
Enclosures:
1.
List of Recently Issued IE Bulletins cc w/ enc 1:
H. L. Abercrombie, Plant Superintendent l
R. E. Rogers, Project Engineer l
H. N. Culver, Chief, Nuclear Safety Review Staff H. J. Green, Division Director 8101050 353
4 4
SSINS No.
6820 Accession No.
8012170482 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 December 19, 1980 IE Bulletin No. 80-25: OPERATING PROBLEMS WITH TARGET ROCK SAFETY-RELIEF VALVES AT BWRs Description of Circumstances:
Five events have occurred over a three-month period involving two types of malfunctions of the Target Rock (TR) safety-relief (S/R) valves at Boston Edison Company's Pilgrim Nuclear Power Station Unit 1.
On two occasions (July 25 and August 1, 1980), the "D" S/R valve failed to open in response to manual demand.
This same "D" valve failed to reclose in response to manual control actions on October 1, 1980. On October 7 and 31, 1980, the "A" S/R valve opened spuriously while the reactor was operating at power and did not reclose in response to repeated attempts until the reactor was shut down and the reactor coolant system depressurized. The first three events represented failures of the S/R valve, whereas the last two events resulted from failures of the nitrogen supply system pressure regulation.
The S/R valves at Pilgrim are two-stage, pilot-operated, dual purpose valves designed by Target Rock Corporation in accordance with GE criteria for service application in the GE BWR main steam system.
The two-stage S/R valve has been designed to replace the TR three-stage S/R valve that had a tendency to leak at the pilot valve and thereby keep the main disk from reseating.
The replacement of the three-stage valves at Pilgrim was accomplished during the refueling outage that was completed in May 1980.
The Pilgrim reactor has four of the two-stage S/R valves installed plus two spring-loaded safety valves.
When the "D" S/R valve failed to open on July 25, 1980, this event was determined to be caused by a failure of its solenoid actuator to function.
During fabrication, the excessive use of Loc-tite (i.e., a trademark adhesive for nute and bolts) caused the solenoid plunger to adhere to the bonnet, thus preventing pneumatic pressure from entering the pncumatic operator.
When the second failure of the "D" valve to open on August 1, 1980 was inveatigated, no discrete cause was found. The investigation involved the removal, disassembly, inspection and testing of only the top-works of the valve.
It did not include, however, a corresponding inspection and testing of the main-stage internals including the piston and guide.
The October 1, 1980 failure of the "D" valve to reclose was concluded to be caused by foreign material being lodged between piston and guide of the main stage of the valve. This conclusion was reached when scoring marks on the surfaces of the piston and guide were found, although no foreign material was recovered.
IEB 80-25 December 19, 1980 Page 2 of 3 The two remaining events of October 7 and 31, 1960 involved the "A" S/R valve that spuriously. opened and depressurized the reactor coolant system.
These ever.ts represented failures of the pneumstic system when excessive pressure in the nitrogen supply system caused the "A" valve to open and then to stay open.
The events were addressed in lE Information Notice No. 80-40, " Excessive Nitrogen Supply Pressure Actuates Safety-Relief Valve Operation to Cause Reactor Depressurization," that was issued on November 7, 1980.
General Electric recently provided recommendations with regard to these two events caused by high pneumatic supply pressure.
Action to be Taken by Utilities with BWR Plants with Operating Licenses or Near-Term Operating Licenses:
1.
If your facility has not yet installed or changed or is presently in the process of changing to the two-stage S/R valves, initiate appropriate quality control procedures to assure inspection of the solenoid actuators for excess Loc-tite prior to operation.
If the solenoid actuator manu-factured by Target Rock Corporation is aiready installed in your facility, confirm its operability either by its operational performance (i.e., it has functioned as designed following an aging period of about 3 months in the higher temperature environment of power operating conditions) or by functional testing at full pressure during the next refueling shutdown of the facility.
Include in your report the results of all attempts to operate the two-stage S/R valve (s).
2.
In the event that a'S/R valve, regardless of make or model (e.g., both two or three stage), fails to function as designed, excepting for pressure setpoint requirements, and the cause of the malfunction is not clearly determined, understood, and therefore corrected, standard operating procedures shall require that the entire valve be removed from service, disassembled, inspected, adjusted, and pressure setpoint tested with steam for proper operation prior to returning the valve to service.
These overhaul requirements shall be at least equivalent to those applicable to periodic surveillance rehabilitation requirements. Appropriate revisions l
to your operating procedures shall be made to include these requirements.
3.
A review of your S/R valve pneumatic supply systems shall be performed to determine the potential for and magnitude of an overpressure condition.
The determined overpressure potential of the pneumatic supply shall be compared with the maximum operating pressure capabilities of the solenoid i
actuator valves serving the S/R valves, so as to determine whether supply.
pressure could result in valve malfunction.
Protective devices (such as relief valves) shall be installed in the proximity of the S/R valves and set to protect against supply pressure in excess of the operating pressure capabilities of the solenoid actuator device.
In addition, consideration should be given to modification or replacement to reduce the sensitivity of the solenoid actuator to pneumatic supply overpressure.
Further, the failure, either high or low, of the pneumatic supply system shall be annunciated to the control room operator. The annunciated supply p.-essure should be measured at a location as close as practical to the S/R i
m
o IEB 80-25 December 19, 1980 Page 3 of 3 valves and downstream of any check valve connecting two or more pneumatic sources. Appropriate operating procedures shall be provided to guide operator response to such an occurrence of high or low supply pressure.
4.
The results of your review in response to each of the three items above shall be provided within 90 days of the date of this bulletin. The system upgrading identified in Item 3 shall be completed within 6 months of the time that you conclude a replacement or modification would be made and the necessary parts are available; this upgrading shall be reported when completed.
Provide written reports as required above, signed under oath or affirmation, under the provisions of Section 182a of the Atomic Energy Act of 1954.
Reports shall be submitted to the Director of the appropriate Regional Office and a copy forwarded to the Director, Office of Inspection and Enforcement, NRC, Washington, D.C. 20555.
This request for information was approved by GAO under a blanket clearance number R0072 which expires November 30, 1983.
Comments on burden and duplication should be directed to U. S. Getoral Accounting Office, Regulatory Reports Review, Room 5106, 441 Eighth Street, N. W., Washington, D. C. 20548 i
t l
l
C IEB 80-25 December 19, 1980 RECENTLY ISSUED IE BULLETINS Bulletin No.
Subject Date Issued Issued To 80-25 Operating Problems with 12/19/80 To specified BWRs Target Rock Safety-Relief with an OL & all Valves at BWRs BWRs with a CP Supplement 4 Failure of Control Rods 12/18/80 To specified BWRs to 80-17 to Insert During a Scram with an OL & All at a BWR BWRs with a CP 80-24 Prevention of Damage 11/21/80 All power reactor Due to Water Leakage facilities with Inside Containment OL or CP (October 17, 1980 Indian Point 2 Event) 80-23 Failures of Solenoid 11/14/80 All power reactor Valves Manufactured by facilities with Valcor Engineering OL or CP Corporation 80-21 Valve yokes supplied by 11/6/80 All light water Malcolm Foundry Company, Inc.
reactor facilities with OLs or cps Supplement 3 Environmental Qualification 10/24/80 All power reactor to 79-01B of Class IE Equipment facilities with an OL Supplement 2 Environmental Qualification 9/30/80 All power reactor to 79-01B of Class IE Equipment facilities with an OL 80-22 Automation Industries, 9/11/80 All radiography Model 200-520-008 Sealed-licensees source Connectors 79-26 Boron Loss from BWR 8/29/80 All BWR power Revision 1 Control Blades facilities with an OL l
l 80-20 Failures of Westinghouse 7/31/80 To each power l
Type W-2 Spring Return reactor facility to Neutral Control Switches in your region with an OL or a CP l
OL = Operating License CP = Construction Permit l
l l