ML20128N498
| ML20128N498 | |
| Person / Time | |
|---|---|
| Site: | Shoreham File:Long Island Lighting Company icon.png |
| Issue date: | 07/22/1985 |
| From: | Wild P STONE & WEBSTER ENGINEERING CORP. |
| To: | Taylor J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| REF-PT21-85-339-000 PT21-85-339, PT21-85-339-000, NUDOCS 8507260217 | |
| Download: ML20128N498 (3) | |
Text
i STONE 6 WEBSTER ENGINEERING CORPORATION 245 SUMMER STREET. BOSTON, M ASS ACHU SETTS ADDRESS ALL CORRESPONDENCE TO P.O. BOX 2325. BOSTON M A 02107 W U. TELEX 94-0001 SOsTON 94-0977 DESIGN RM M LL. N. J.
POR S "CL n'al'A."'.
gm,.~o.gioO~
cNamirRm W AS M4hG TON. D C.
Mr. James M. Taylor July 22, 1985 Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 NOTIFICATION OF DEFECT SHOREHAM NUCLEAR POWER STATION LONG ISLAND LIGHTING COMPANY Stone & Webster Engineering Corporation (SWEC), pursuant to the provisions of 10CFR21, hereby provides notification of a " defect" concerning the Shoreham Nuclear Power Station owned by Long Island Lighting Company (LILCO) and for which SWEC provided both engineering and construction services.
In accordance with the reporting requirements of Section 21.21(b)(3), the following information is submitted:
1.
Name and address of the individual informing the Commission:
Mr. P. A. Wild Director of Engineering Stone & Webster Engineering Corporation P.O. Box 2325 Boston, MA 02107 ii.
Identification of the facility, or the basic component supplied for such facility, which contains a defect:
Shoreham Nuclear Power Station Rochester Instrument Systems Type RIS PR-2035 undervoltage relays lii. Identification of the firm constructing the facility or supplying the basic component which contains a defect:
Basic component supplied by Rochester Instrument Systems, Inc., 225 North Union Street, Rochester, NY 14605 iv.
Nature of the defect and the safety hazard which could be created:
Type RIS PR-2035 undervoltage relays, installed in the 4,160 V emergency switchgear for degraded voltage protection, have demonstrated a tendency to drift from their calibrated h
8507260217 850722 1
PDR ADOCK 050003 2 D
S i
s JMT 2
setpoints.
Recalibration attempts revealed continued drift-ing and loss of the specified dead band values.
The relays are connected two in series to each bus to provide a two out of two logic, and the problems have been exhibited in three of six installed relays, one of which was confirmed by the manufacturer.
The cases to consider for analyzing setpoint drift for the RIS PR-2035 undervoltage relay are (1) a drift to raise the setpoint, (2) a drift to lower the setpoint coincident with a loss of offsite power, and (3) degraded voltage on the system.
No substantial safety hazard would result from the first two cases.
For a degraded voltage condition and a setpoint drift below the 91.7 percent emergency bus voltage at which the relay setpoint is calibrated, it is possible that no signal will initiate start of a single diesel generator.
If only one emergency bus has a low drift on its respective undervoltage relay, and one assumes a single failure of a diesel generator on another bus, there will not be sufficient power to support the safety-related systems.
This is due to the fact that a bus with degraded voltage (greater than the lower setpoint of the RIS relay but less than 91.7 percent) will not be ensured of energizing starting coils and operating relays of down-stream equipment.
When assuming a se. point drift for all relays in the same direction the condition would become more aggravated.
In this mode, the undervoltage relays on each bus would have a setpoint below 91.7 percent and no diesel generator would start up for the degraded system voltage condition.
Thus the operation of equipment for all safety-related functions will be subject to degraded voltage condi-tions.
This represents a major reduction in the degree of protection provided to the public health and safety and could create a substantial safety hazard.
v.
Date on which information of such defect was obtained:
July 22, 1985 vi.
In the case of a basic component which contains a defect, the number and location of all such components in use at, supplied for or being supplied for facilities subject to the regulation:
Shoreham Nuclear Power Station is, to date, the only project for which SWEC has applicable engineering and design respon-sibility determined to have this defect.
Should this in-formation change, this report will be amended accordingly.
L_
u.
. to JNr 3
vii. Corrective action which has been taken; name of individual or organization responsible; and length of time taken to complete the action:
LILCO replaced the defective relays with newly canufactured units.
The defective units were returned to Rochester Instrument Systems, modified and returned to LILCO for use as spares.
viii. Advice related to the defect that has been given to purchasers or licensees:
No other action apart from that specified above.
If you require any further information, please contact Mr. R. B. Bradbury at (617) 589-1291.
P. A. Wild Director of Engineering JBS:VMB