ML20072M793
| ML20072M793 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 07/01/1983 |
| From: | Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE, YANKEE ATOMIC ELECTRIC CO. |
| To: | Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, SBN-526, NUDOCS 8307150096 | |
| Download: ML20072M793 (4) | |
Text
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E 1671 Woresser Rood j
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m 01701 Pubic Service of New Hampshire (617) - 872 - 8100 July 1, 1983 SBN-526 T.F. Q2.2.2 United States Nuclear Regulatory Commission
, dd3 Region I
,i ' 7"e d 4 631 Park Avenue King of Prussia, PA 19406 Attention:
Mr. Richard W. Starostecki, Director Division of Project and Resident Programs Re fere nces :
(a) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444 (b) Telecon of February 16, 1983, A. L. Legendre (YAEC) to J. Wiggins (NRC, Region I)
(c)
PSNH Letter, dated March 18, 1983, " Interim 10CFR50.55(e)
Report; Westinghouse 7300 Series Process I&C System Cabinets," J. DeVincentis to R. W. Starostecki (d) PSNH Letter, dated May 20, 1983, " Interim 10CFR50.55(e)
Report; Westinghouse 7300 Series Process I&C System Cabinets", J. DeVincentis to R. W. Starostecki (e) Telecon of June 17, 1983, A. L. Legendre (YAEC) to Eugene Kelly (NRC, Region I)
(f) Westinghouse Letter, dated June 1, 1983, E. P. Rahe to R. C. DeYoung
Subject:
Interim 10CFR50.55(e) Report; Westinghouse 7300 Process Protection System NLP Card Heat Sinks and NTC Card Relays
Dear Sir:
On February 16, 1983 and June 17, 1983, we provided telephone notification of two potential 10CFR50.55(e) deficiencies affecting the Westinghouse 7300 Process Protection System.
The following descriptions and corrective actions are based on a Westinghouse letter to the Office of Inspection and Enforcement (Reference (f)). The two deficiencies are i
ng described below:
wo l E 1.
HEAT SINKS ON NLP CARD, REFERENCES (b), (c), AND (d) 1 00 00 GQ Description of Deficiency 05 Heat sink adhesive failures have been identified at several utilities including Seabrook Station and were reported to 4
Westinghouse as field deficiencies.
All reported field failures om no eo.m 1000 Elm St., P.O. Box 330. Manchester, NH O3105. Telephone (603) 669-4000 TWX 7102207595
T United States Nuclear Regulatory Commission July 1, 1983 Attention:
Mr. Richard W. Starostecki Page 2 occurred only on the Loop Power Supply (NLP) cards. Westinghouse has determined that NLP printed circuit cards shipped from Westinghouse Industry Electronics Division (WIED) between August 1, 1980 and September 1,1982 were equipped with a thermal heat sink assembly on the inverter transistors that are subject to potential failures in the adhesive bond in the thermal link assembly. The adhesive bond is between an insulating washer and the thermal link.
Failure of the bond can cause the heat sink plate to separate from the thermal links and fall off of the printed circuit board.
The plate is conductive metal and under certain circumstances could cause shorting of low level signals if it became wedged between cards in the card frame.
The printed circuit boards which have experienced heat sink separation are:
SNLP Sub-level 18 and above 6NLP Sub-level 18 and above Note: Previous Sub-levels did not contain heat sinks. The assembly sub-level identification sticker is attached to the solder side of the card near the front edge.
It is not the revision identified on the front edge.
The adhesive failure mechanism or expected number of hours of system operation before failure is not defined.
All reported problems have occurred under. normal system usage or storage., To date, these heat sink adhesive failures have not resulted in any damage to the Westinghouse 7300 Process Protection System nor have these failures resulted in any loss of system safety functions.
At the time of this report, it has not been determined which of the two types of circuit boards have been installed in the Seabrook 7300 Process Protection System.
Corrective Action Replacements for the heat sinks that are subject to this potential adhesive failure mechanism will be provided by Westinghouse. These affected heat sinks can be identified by inspection of the printed circuit card.for hex nuts visible on the top side of the assembly..
The new style heat sink has screw heads visible from the top side of the assembly.
2.
NTC CARD RELAY, REFERENCE (e)
Description of Deficiency During siesmic testing of the Temperature Channel Test (NTC) card, contact bounce was experienced in the mercury relay' utilized on this card.. This intermittent contact bounce will result in signal saturation of the downstream RTD Amplifier (NRA) card in the Thot and Teold circuits of the Westinghouse 7300 Process Protection System.
In these systems,. filters are adjusted to. maintain a total time constant of approximately two seconds for the RTD/ filter combination. Since the filter is downstream of the relay, the
l
.s 1
United States Nuclear Regulatory Commission July 1, 1983 i
Attention:
Mr. Richard W. Starostecki Page 3
)
characteristics of the channel response depend on the time constant of the filter. For RTDs specified by Westinghouse, the filter has l
been set at either zero or two seconds depen 'ing on the type of RTD l
(fast or slow response) utilized. For applicutions utilizing unfiltered signals, as is the design for Seabrook Station, saturation of the NRA card could delay initiation of the Overtemperature - Delta T and Overpower - Delta T trips.
For applications utilizing a filtered signal, NRA card saturation would not prevent plant trips, but could result in a spurious plant trip.
This problem only occurs as a result of contact bounce induced by a siesmic event.
Corrective Action A replacement relay is being developed and tested by Westinghouse.
These replacement relays will be installed in Seabrook Station subsequent to development and testing.
We will submit a final report to Region I upon verification that the heat sink modification is complete and replacement relays are installed at Seabrook Station.
Since the replacement parts are currently being fabricated / developed by Westinghouse, no schedule for corrective action is available at this time. We will provide a status report by January 5,1984 if a final report has not been filed by that time.
Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY 2d,suA 4) y J. DeVincentis Project Nhnager MH0/ gad cc: Atomic Safety and Licensing Board Service List Director, Office of Inspection and Enforcement United States Nuclear Regulatory Commission Washington, DC 20555 l
s William S. Jordan, III, Esquire Ms. Olive L. Tash Harmon & Weiss Designated Representative of 1725 I Street, N.W. Suite 506 thi Town of Brentwood Washington, DC 20006 R.F.D. 1, Dalton Road Brentwood, NH 03833 Roy P. Lessy, Jr., Esquire Office of the Executive Legal Director Edward F. Meany U.S. Nuclear Regulatory Commission Designated Representative of Washington, DC 20555 the Town of Rye 155 Washington Road Robert A. Backus, Esquire Rye, NH 03870 116 Lowell Street P.O. Box 516 Calvin A. Canney Mancehster, NH 03105 City Manager City Hall Philip Ahrens, Esquire 126 Daniel Street Assistant Attorney General Portsmouth, NH 03801 Department of the Attorney General Augusta, ME 04333 Dana Bisbee, Esquire Assistant Attorney General Mr. John B. Tanzer Office of the Attorney General Designated Representative of 208 State House Annex the Town of Hampton Concord, NH 03842 5 Morningside Drive Hampton, NH 03842 Anne Verge, Chairperson Board of Selectmen Roberta C. Pevear Town Hall Designated Representative of South Hampton, NH 03842 the Town of Hampton Falls Drinkwater Road Patrick J. McKeon Hampton Falls, NH 03844 Selectmen's Office 10 Central Road Mrs. Sandra Gavutis Rye, NH 03870 Designated Representative of the Town of Kensington David R. Lewis, Esquire RFD 1 Atomic Safety and Licensing Board East Kingston, NH 03827 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Jo Ann Shotwell, Esquire Assistant Attorney General Mr. Angie Machiros Environmental Protection Bureau Chairman of the Board of Selectmen Department of the Attorney General Town of Newbury One Ashburton Place, 19th Floor Newbury, MA 01950 Boston, MA 02108 Maynerd B. Pearson Senator Gordon J. Humphrey 40 Monroe Street U.S. Senate Amesbury, MA 01913 Washington, DC 20510 (Attn: Tom Burack)
Senator Gordon J. Humphrey 1 Pillsbury Street Diana P. Randall Concord, NH 03301 70 Collins Street (Attn: Herb Boynton)
SEabrook, NH 03874 Richard E. Sullivan, Mayor Donald E. Chick City Hall Town Manager Newburyport, FDL 01950 Town of Exeter 10 Front Street Exeter, NH 03833