ML18031A063
| ML18031A063 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 12/19/1978 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Curtis N PENNSYLVANIA POWER & LIGHT CO. |
| References | |
| NUDOCS 7901030045 | |
| Download: ML18031A063 (7) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION AEGION I 631 PARK AVENUE KING OF PRUSSIAN PENNSYLVANIA I 9406 December 19, 1978
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-l Docket Nos.
50-0-388 Pennsylvania Power 5 Light Company
'TTN:
Nr. Norman W. Curtis
,Yice President Engineering and Construction (N-4) 2 North Ninth Street Allentown, Pennsylvania 18101 Gentlemen:
h The enclosed Bulletin 78-14 is forwarded to you for information.
No written response is required.
If you desire additional information regarding this matter,-please contact this office.
Sincerely, oyce H. Grier Director
Enclosures:
l.
List of IE Bulletins Issued in 1978 cc w/encls:
'A. R. Sabol,
- Nanager, Nuclear guality Assurance W.'. Barberich,* Licensing Engineer /
0
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Bulletin No. 78-14 Date:
December 19, 1978 Page 1 of 3
- DETERIORATION OF BUNA-N COMPONENTS IN ASCO SOLENOIDS Description of Circumstances:
Following a reactor scram at the Monticello Nuclear Power Station on July 27,
- 1978, one control rod was determined to have a slow scram insertion time.
While measuring the average control rod scram insertion
. times (as required by Technical Specifications),
the same control rod failed to scram.
Subsequent investigation revealed that a Buna-N disc in the scram pilot.valve solenoid core assembly had fractured.
Small pieces of the Buna-N material wedged between the core assembly and the valve pilot body.
This prevented proper movement of the core assembly (plunger),
and thus prevented the valve from properly venting control air from the scram valves.
A similar event occurred during scram testing on June 5,
1978.
On both occasions the control rod failed to scram during control rod surveillance testing.
In these instances, had a scram occurred during normal operation of the reactor, the affected rods would have inserted by action of the backup scram solenoid valves.
The reactor was placed in cold shutdown on July 28, 1978.
All of the scram pilot solenoid valves and scram backup valves were disassembled and inspected.
Six additional fractured Buna-N discs were found, all in scram pilot solenoid valves.
Northern States Power Company replaced the plunger Buna-N discs in all 242 scram pilot valves and the 2 backup scram valves.
In addition to the Monticello failures, similar events were recently reported from the Big Rock Point and Pilgrim facilities.
At Big Rock
- Point, two failures were experienced in October while at Pilgrim one failure was found in July and two in December.
All of these failures were encountered during surveillance testing.
General Electric had previously issued Service Information Letters, SIL 128 (March 31, 1975) and SIL 128 Revision I (January 30, 1976),
addressing the deterioration through natural aging of Buna-N components in CRD scram pilot valves.
These letters recommended that a maintenance program be adopted which replaced certain Buna-N components in scram pilot valves on a regularly scheduled basis.
However, the Buna-N discs
IE Bulletin No. 78-14 Date:
December 19, 1978 Page 2 of 3 in the scram pilot valve core assemblies were not included in these r ecommendations.
As.a result of the Monticello experience and subsequent investigation, General Electric has issued in August 1978, SIL 128 Revision 1, Supplement 1, which recommends that all BWR operators take the following actions:
"Establish a preventive maintenance program to replace all core assemblies, diaphragms and associated parts in all CRD scram pilot valves, backup scram valves, scram discharge volume vent and drain pilot valves, and scram discharge volume test valves, at periodic intervals.
The Buna-N parts used in these valves have at least a seven year shelf and in-service life from the packaging date on the rebuild kit.
Thus, the valves should be rebuilt periodically to assure that the Buna-N parts are not used in excess of seven years.
It is recommended that the work be scheduled in any one outage such that the associated CRDs are selected from a distributed checkerboard pattern.
The remaining valves can be rebuilt during subsequent outages."
For clarity, it is noted that the above seven year limit recoranended by GE includes all of the time from packaging through installation to the end of service life.
In addition, it is noted that the parch 31, 1975 issue of SIL 128 stated that -the design specification for Buna-N specified a minimum design life of three years.
Action to be Taken by Licensees:
For all GE BWR power reactor facilities with an operating license:
Review Buna-N material applications in your control rod scram systems and determine the time since installation, and for installed
- material, the time since packaging.
2.
3.
Report the results of the review set forth in item 1 above and describe your schedule for replacement, both in response to this Bulletin and for periodic maintenance.
Describe the bases for your schedule of replacement identified in response to item 2 above.
Justify any proposed replacement time in excess of three years.
IE Bulletin No. 78-14 Date:
December 19, 1978 Page 3 of 3 4.
Within 45 calendar days of the date of issue of this Bulletin, report in writing to the Director of the appropriate NRC Regional Office, the results of your review, schedule and bases for replacement with regard to Items 1 through 3.
A copy of your report should be sent to the United States Nuclear Regulatory Coranission, Office of Inspection and Enforcement, Division of Reactor Operations Inspection, Washington, D.C.
20555.
For all BWR facilities with a construction permit and all other power reactor facilities with an operating license or construction permit, this Bulletin is for information only and no written response is required.
Approved by GAO B180225 (R0072); clearance expires 7/31'/80.
Approval was given under a blanket clearance specifically for identified generic problems.
Enclosure:
IE Bulletins Issued in 1978
LISTING OF IE BULLETINS ISSUED IN 1978 IE Bulletin No. 78-14 Date:
December 19, 1978 Page 1 of 2 Bulletin Subject No.
Date Issued Issued To 78-01 78-02 78-03 78-04 78-05 78-06 78-07 Flammable Contact-Arm Retainers in G.E.
CR120A Relays Terminal Block qualification Potential Explosive Gas Mixture Accumula-tions Associated with BWR Offgas System Operations Environmental guali-fication of Certain Stem Mounted Limit Switches Inside Reactor Containment Malfunctioning of Circuit Breaker Auxiliary Contact Mechanism-General Model CR105X Defective Cutler-
- Hammer, Type M Relays With DC Coils Protection afforded by Air-Line Respirators and Supplied-Air Hoods 1/16/78 1/30/78 2/8/78 2/21/78 4/14/.78 5/31/78 6/12/78 All Power Reactor Facilities with an Operating License (OL) or Construction Permit (CP)
All Power Reactor Facilities with an OL or CP All BWR Power Reactor Facilities with an OL or CP All Power Reactor Facilities with an OL or CP All Power Reactor Facilities with an OL or CP All Power Reactor Facilities with an OL or CP All Power Reactor Facilities with an OL, all Class E and F
Research Reactors with an OL, all Fuel Cycle Facilities with an OL, and all Priority 1
Material Licensees
LISTING OF IE BULLETINS ISSUED IN 1978 IE Bulletin No. 78-14 Date:
December 19, 1978 Page 2 of 2 Bulletin Subject No.
Date Issued Issued To 78-08 78-09 78-10 78-11 78-12 78-12A Radiation Levels from Fuel Element Transfer Tubes BWR Drywell Leakage Paths Associated with Inadequate Drywell Closures Bergen-Paterson Hydraulic Shock Suppressor Accumulator Spring Coils Examination of Mark I Containment Torus Welds Atypical Weld Material in Reactor Pr essur e Vessel Welds Atypical Weld Material in Reactor Pressure Vessel Welds 6/12/78 6/14/78 6/27/78 7/21/78 9/29/78 11/24/78 All Power, Test, and Research Reactor Facilities with an OL having Fuel Element Transfer Tubes.
All BWR Power Reactor Faci1 ities with an OL (for action) or CP (for information).
All Power Reactor Facilities with an OL or CP BWR Power Reactor Facilities with an OL for action:
Peach Bottom 2 and 3, squad Cities 1
and 2, Hatch 1, Monticello and Vermont Yankee.
All other BWR Power Reactor Facilities with an OL for information.
All Power Reactor Facilities with an OL or CP.
All Power Reactor Facilities with an OL or CP 78-13 Failures in Source Heads 10/27/78 of Kay-Ray, Inc.,
Gauges Models 7050,-
- 7050B, 7051
- 7051B, 7060,
- 7060B, 7061 and 7061B All General and Specific Licensees with the subject Kay-Ray Gauges