ML20033D214
| ML20033D214 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 11/19/1981 |
| From: | Martin T Public Service Enterprise Group |
| To: | Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8112070386 | |
| Download: ML20033D214 (4) | |
Text
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Thomas J. Martin Public Service Electric and Gas Company 80 Park Plaza Newark, N.J. 07101 201/4304316 Vice President Mailing Address:
P.O.
Box 570, Newark, N.J.
07101 Engineering and Construction November 19,.'981
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i Mr. Ronald C. Haynes j-e#
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U.
S. Nuclear Regulatory Commission 9
Office of Inspection and Enforcement g
Region I 4
631 Park Avenue King of Prussia, Pennsylvania 19406
Dear Mr. Haynes:
LIMITORQUE VALVE OPERATORS 10CFR50.55(e), SIGNIFICANT DEFICIENCY NO. 1 AND 2 UNIT 3 HOPE CREEK GENERATING STATION On June 19, 1981, a verbal report was'made to Region I, Office of Inspection and Enforcement representative, Mr.
R.
Gallo, advising of a potential'significant deficiency con-cerning deficiencies found in valve operators manufactured by Limitorque of Lynchburg, Virginia.
An interim report was submitted to your office on July 17, 1981, describing analy-sis to be performed.
The following are the results of this effort.
1.
Summary of the Problem:
Our original report identified three specification non -
conformances in a sample of operators:
a.
Fiber shims under contact screws.
b.
Unidentified terminal blocks.
c.
Damaged terminal blocks.
The questions concerning the terminal blocks have been evaluated and are not significant.
Th'e use of fiber shims'under the contact screws has been determined to be reportable.
In addition, a survey of Limitorque operators on-site fo'r other defects l detected some poor wiring practices, such as:-
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Mr. Ronsid C. Haynes 11/19/81 a.
Conductor insulation to crimp barrel distance ex-ceeds 1/16 inch.
b.
Lack of conductor protrusion through the crimp barrel.
2.
Analysis of Safety Implications:
Our Architect / Engineer, Bechtel, advises the fiber shims problem was originally detected at the Susquehanna site and the following analysis performed at Susquehanna is applicable to Hope Creek.
Adjustments and pre-operational checks on both safety related and non-safety related motor-operated
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valves. made prior to post-construction startup tests of Limitorque valve operations models SMB-000, revealad that the stationary electrical contacts on the "close" side of the torque switch had loosenea, The torque switches in question are of the leaf l
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type.
The electrical contacts are small machined i
hex-head cap screws.
Locking devices for the cap screws were not installed.
One pair of cap screws on each torque switch.has one or more fiber shims installed under a metal bridge l
plate.
Limitorque stated that the fiber shims were used to make the height of both pairs of cap screws equal.
The screws have no-locking device because the height of the screw la critical and lock-washers would raise the height.
l These fiber shims installed at the factory under the proper torque value of six inch-lbs, (Limitorque re-quirements) may have a tendency to relax with time, thus relieving the preload on the screw.
The poor wiring practices could also lead to the.
failure ofEthe unit to function.
I Limitorque operators are used in many_ systems required for safe shutdown.
A typical example is valves instal-led' in the Reactor Water Cleanup (RWCU) system..The above valves are part of the containment isolation sys-tem and failure-of the-valves to operate _would be a breach of the-containment boundary.
i
e Mr. Ronald C.
Haynes 11/19/81 Although none of the contact screws checked at Hope Creek had loosened, the same root cause for the loose screws identified at Susgaehanna exists at Hope Creek.
Therefore, our corrective action is based on the assump-
, tion that the problem eventually could occur at Hope Creek.
l 3.
Corrective Actions:
a.
Bechtel has instructed our suppliers of motor-oper-ated valves in safety-related systems (BIF, Anchor /
Darling, Rockwell) to:
(1) apply Loctite to the contact screws and torque them to 6 lb-inches on all SMB-00 and SMB-000 operators in-house, and (2) to accept, in the future, only those operators having metallic shims in lieu of fiber.
Limitorque discontinued the use of fiber shims in November, 1980.
i b.
Bechtel field forces will correct delivered opera-tors by applying Loctite or replacing the fiber shims with metal shims.
c.
Bechtel has issued a document entitled, " Guidelines for Inspection of Limitorque Operators" and directed their field forces to inspect all Limitorque opera-tors in safety-related applications accordingly.
These instructions include the wiring problems noted in the Summary section of this report.
When the in-spection of the valve operators is completed, Bech-tel will determine the scope of the rework required to correct the problems found during the inspec-tion.
Also, a decision will be made which will identify the source of the rework, i.e.,
- jobsite, valve supplier,or Limitorque.
d.
Bechtel has issued instructions to all Supplier Quality Representatives (SQR) with motor-operated valve assignments, requiring that Limitorque opera-tors size SMB-00 and SMB-000 be inspected for the inclusion of fiber shims.
The " Guidelines for In-spection of Limitorque Operators" was issued on October 15, 1981, to all'SQRs involved with procure-ments that include Limitorque Operators with in-structions to apply the inspection criteria during inspections performed at the valve supplier's facilities.
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Mr. Ronald C.
Haynes 11/19/81' We expect to have all inspecticns and corrective actions completed by December.31, 1982.-
Complete records of all actions will be available on-site for review by your inspectors.
Very truly yours, i
CC:
Office of Inspection and Enforcement Division of Reactor Construction - Inspection Washington, D.C.
NRC Resident Inspector - Hope Creek P.
O. Box 241 Hancocks Bridge, NJ 08038 HN22 1/4 T
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