ML18081A767
| ML18081A767 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 11/30/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Martin T Public Service Enterprise Group |
| References | |
| NUDOCS 7912190071 | |
| Download: ML18081A767 (5) | |
Text
Docket No. 50-311 e
UNITED STATES e
NUCLEAR REGULATORY COMMISSION REGION I 631 PARK AVENUE KING OF PRUSSIA, PENNSYLVANIA 19406 November 30, 1979 Public Service Electric and Gas Company ATTN:
Mr. T. J. Martin Vice President - Engineering and Construction 80 Park Place Newark, New Jersey 07101 Gentlemen:
The enclosed IE Bulletin No. 79-27 is forwarded for action. A written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely,
~
- yj?,~
~yce H.
~rier Director
Enclosures:
- l.
- 2.
List of Recently Issued IE Bu1*1etins CONTACT:
D. L. Caphton (215-337-5308) cc w/encls:
E. N. Schwalje, Manager - Quality Assurance
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ENCLOSURE 1 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 SSINS No.:
6820 Accession No.:
7910250499 IE Bulletin No. 79-27 Date: November 30, 1979 Page 1 of 3 LOSS OF NON-CLASS-1-E INSTRUMENTATION AND CONTROL POWER SYSTEM BUS DURING OPERATION Description of Circumstances:.
On November 10, 1979, an event occurred at the Oconee Power Station, Unit 3, that resulted. in loss of power to a non-class-1-E 120 Vac single phase power.
panel that supplied power to the Integrated Control System (ICS) and the Non-Nuclear Instrumentation (NNI) System.
This loss of power resulted in control system malfunctions and significant loss of information to the control room operator.
Specifically, at 3:16 p.m., with Unit 3 at 100 percent power, the main condensate pumps tripped, apparently as a result of a technician performing maintenance on the_hotwell level control system.* This led to reduced feedwater flow to the steam generators, which resulted in a reactor trip due to high coolant system pressure and simultaneous turbine trip at 3:16:57 p.m.
At 3:17:15 p.m., the non-class-1-E inverter power supply feeding all power to the integrated control system (which provides proper coordination of the reactor, steam generator feedwater control, and turbine) and to one NNI channel tripped and failed to automatically transfer its loads from the DC power source to the regulated AC power source.
The inverter tripped due to b.lown fuses.
Loss of power to the NNI rendered contra l room i nd.i caters and recorders for the reactor coolant system (except for one wide-range RCS pressure recorder) and most of the secondary plant systems inoperable, causing loss of indication for systems
- used for decay heat removal and water addition to the reactor vessel and steam generators.
Upon loss of power, all valves controlled by the ICS assumed their respective failure positions.
The loss of power existed for approximately three minutes, until an operator could reach the equipment room and manually switch the inverter to the regulated AC source.
The above event was discussed in IE Information Notice No. 79-29, issued November 16, 1979.
NUREG 0600 "Investigation into the March 28, 1979 TMI Accident" also discusses TMI LER 78-021-03L whereby the RCS depressurized and Safety Injection occured on loss of a vital bus due to inverter failure.
Actions to Be Taken by Licensees IE Bulletin No. 79-27 Date: November 30, 1979 Page 2 of 3 For all power reactor facilities with an operating license and for those nearing completion of construction (North Anna 2, Diablo Canyon, McGuire, Salem 2, Sequoyah, and Zimmer}:
- 1.
Review the class-1-E and non-class 1-E buses supplying power to safety and non-safety related instrumentation and control systems which could affect the ability to achieve a cold shutdown condition using existing procedures 0r procedures developed under item 2 below.
For each bus:
a) identify and review the alarm and/or indication provided in the control room to alert the operator to the loss of power to the bus.
b) tdentify the instrument and control system loads connected to the bus and evaluate the effects of loss of power to these loads including the ability to achieve a cold shutdown condition.
cl describe any proposed design modifications resulting from these reviews and evaluations, and your proposed schedule for implementing those modtfications.
- 2.
Prepare emergency procedures or review existing ones that will be used by control room operators, including procedures required to achieve a cold*
shutdown condition, upon loss of power to each class 1-E and non-class 1-E bus supplying power to safety and non-safety related instrument and control systems.
The emergency procedures should include:
a) the diagnostics/alarms/indicators/symptom resulting from the review and evaluation conducted per item 1 above.
b) the use of alternate indication and/or control circuits which may be powered from other non-class 1-E.or class 1-E instrumentation and control buses.
c) methods for restoring power to the bus.
Describe any proposed design modification or administrative controls to be implemen~ed resulting from these procedures, and your proposed schedule for implementing the changes.
- 3.
Re-review IE Circular No. 79-02, Failure of 120 Volt Vital AC Power Suppltes, dated January 11, 1979, to include both class 1-E and non-class 1-E safety related power supply inverters.
Based on a review of operating experience and your* re-review of IE Circular No. 79-02, describe any proposed design modifications or administrative controls to be implemented as a result of the re-review.
IE Bulletin No. 79-27 Date: November 30, 1979 Page 3 of 3
- 4.
Within 90 days of the date of this Bulletin, complete the review and evaluation required by this Bulletin and provide a written response describing your reviews and actions taken in response to each item.
Reports should be submitted to the Director of the appropriate NRC Regional Office and a copy should be forwarded to the NRC Office of Inspection and Enforcement, Dtvision of Reactor Operations Inspection, Washington, D.C.
20555.
If you desire additional information regarding this matter~ please contact the IE Regional Office.
Approved by GAO 8180225 (R0072); clearance expires 7/31/80. Approval was gtven under a blanket clearance specifically for identified generic problems.
Bulletin No.
79-22 79-14 (Supplement No. 2) 79;.23 79-24 79-13 (Rev. 2) 79-17 (Rev. 1) 79-25 79-02 (Rev. 2) 79-26 ENCLOSURE 2 RECENTLY ISSUED IE BULLETINS Subject Date Issued Possible Leakage of 9/5/79 Tubes of Tritium Gas Used in Timepieces for Luminosity Same as Title 79-14 9/7/79 Potential Failure of 9/12/79 Emerg~ncy Diesel Gen-erator Field Exciter Transformer Frozen Lines 9/27/79 Cracking in. Feedwater 10/17/79 System Piping Pipe Cracks in Stagnant 10/29/79 Borated Water Systems at PWR Plants Failures of Westinghouse 11/2/79 BFD Relays in Safety-Related Systems Pipe Base Plate Designs 11/8/79 Using Concrete Expansion Bolts Boron Loss From BWR Control Blades 11/20/79 IE Bulletin No. 79-27 Date: November 30, 1979 Page 1 of 1 I
Issued To Each Licensee who Receive Tubes of
- Tritium Gas in Time-pieces for Luminosity Same as 79-14 All Power Reactor Facilities with an OL or CP All Power Reactor Facilities which have either OLs or CPs and are in late stage of con-struct ion All PWRs with an OL and Designated. Ap-plicants (for Action),
All Other Power Reactor Facilities with an OL or CP (for Information)
A 11 PWRs with an OL (for Action).
All other Power Reactor Facilities with an OL or CP (for Information)
All Power Reactor F aci l i ti es wi th an OL or CP (for Action)
All Power Reactor Facilities with an OL or CP All BWR Power Reactor Facilities with an OL