ML19256F442
| ML19256F442 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 11/30/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Goodwin C PORTLAND GENERAL ELECTRIC CO. |
| References | |
| NUDOCS 7912190147 | |
| Download: ML19256F442 (1) | |
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1990 N CALIFORNIA BOULEVARD 0,
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- ,,,a WALNUT CREE K, CALIFORNI A 94596 tiovember 30, 1979 Docket :10. 50-344 Portland General Electric Company 121 S. W. Salmon Street Portland, Oregon 97204 Attention: Mr. Charles Goodwin Assistant Vice President Gentlemen:
The enclosed IE Bulletin ilo. 79-27 is forwarded for action. A written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely, hi12
,d.-
R. H. Engelken Director
Enclosures:
1.
IE Bulletin flo. 79-27 2.
Recently Issued IE Sulletins cc w/ enclosures:
C. P. Yundt, PGE F. C. Gaidos, PGE
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UtlITED STATES SSINS No.: 6820 NUCLEAR REGULATORY CCMNISSION Accession t'o. :
OFFICE OF INSPECTION AND ENFORCE"ENT 7910250499 WASHINGTON, D.C.
20555 t'ovember 30, 1979 IE Rullatin No. 79-27 LOSS OF NON-CLASS-1 ~ INSTRU"ENTATICN AND CONTROL omER SYST 31 BUS 9001T ODEoATION Descrintion of Circumstances:
On Moverber 10, 1979, an event occurred at the Oconee Power Station, Unit 3, that resulted in loss of cower to a non-class-10 120 Vac sincie chase ocwer canel that sucolied cower to the Inteorated Control Systen (ICS) and the Mon-Nuclear Instrurentation (NNI) Systen. This loss of cower resulted in control systen ralfunctions and sicnificar.t loss of information to the control room operator.
Soecifically, at 3:15 o.n., with Unit 3 at 100 cercent cower, the rain condensate comes trioned, aoparentiv as a result of a technician cerforning raintenance on the hotwell level control systen. This led to reduced feedwater flow to the stean qenerators, which resulted in a reactor trio due to hiah coolant systen pressure and sinultaneous turbine trio at 3:16:57 c.n.
At 3:17:15 p.m., the non-class-1-E inverter oower sucaly feeding all oower to the integrated control syster (which provides procer coordination of the reactor, stean generator feedwater control, and turbine) and to one NNI channel trioced and failed to automatically transfer its loads from the DC power source to the regulated AC cober source. The inverter trioced due to blown fuses. Loss of power to the NNI rendered control roon indicators and recorders for the reactor coolant systen (exceot for one wide-rance RCS pressure recorder) and rost of the secondary olant systers incoerable, causino loss of indication for systens used for decay heat reroval and water addition to the reactor vessel and stean qenerators. Upon loss of oower, all valves controlled by the ICS assured their resoective failure posi tions.
The loss of oower existed for anoroximately three minutos, until an coerator could reach the eouionent roon and ranually switch the inverter to the reculated AC source.
The above event was discussed in IE Information "otice No. 79-29, issued Nove-ber 16, 1979.
NUoE'i 0600 "Investication into the March 28, 1979 TMI fccident" also discusses TMI LER 73-021-03L whereby the RC9 denressurized and Safety Injection occured on loss of a vital bus due to inverter failure.
Actions to Be Taken by Licensees For all power reactor facilities with an ooeratino license and #nr those nearina coroletion of construction (North Anna 2, Oiablo Canyon, McGuire, Saler 2, Senuoyah, and Zirrer):
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IE Bul.letin No. 79-27 November 30, 1979 Page 2 of 2 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 acnieve a cold shutdown condition using existing procedures or 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 tb? bus.
b) identify 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.
c) describe any proposed design modifications resulting frcm these reviews and evaluaticns, and your proposed schedule for irplementing those modi fica tions.
2.
Prepare emergency procedures or review existing ones that will be used by control rocm 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 energency procedures should include:
a) the diagnostics / alarms / indicators /symptem 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 implemented 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 Supplies, 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.
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, Division of Reactor Operations Inspection, Washington, D.C.
20555.
If you desire additional information regarding this matter, pleasc contact the IE Regional Office.
Approved by GA0 8180225 (R0072); clearance expires 7/31/80. Approval was given under a blanket clearance specifically for identified generic problems.
162010
IE Bulletin No. 79-27 Enclosure Novebrer 30, 1979 RECENTLY ISSUED IE BULLETINS Bulletin Subject Date Issued Issued To No.
79-26 Dornn Loss Frcr 9M0 11/20/70 all R':o cower raacter Control Blades facilities with an OL 79-25 Failures of Pestirchouse 11/2/79 All onwer reactor RFC o lays In Safety ? elated facilities with an e
Systems OL or CP 79-17 Pir,e Cracks In Stacnant 10/29/79 Al l P'/o 's wi th a n (Rev. 1)
Borated Water Systen At OL and 'or information PWR clants to other nower reactors 79-24 Frozen Lines 9/27/79 All cower reactor facilities which have either OLs or cps and are in the late stace of construction 79-23 Potential Failure of 9/12/79 All Power Reactor Emergency Diesel Facilities with an Generatcr Field Operatina License or Exciter Transformer a construction permit 79-la Seismic Analyses For 9/7/70 All Dower Reactor (Sucolement 2)
As-Built Safety elated Facilities with an Pioin0 Systems OL or a CP 79-22 Dossible Leakane of Tubes 9/5/79 To Each Licensee of Tritium Gas in Time-who Receives Tubes oieces for Luninosity of Tritiun Gas Used in Timecieces
- nr Luninosity 79-13 Crackina in Feedwater 8/10/79 All Desiqnated (Rev. 1)
Systen Piping Aonlicants for OLs 79-02 Pine Succort Base Plate 8/20/79 All newer Reactor (Rev. 1)
Desians Usinn Concrete Facilities with an (Sucolerent 1)
Exoansion Anchor Bolts OL or a CP 79-14 Seisnic Analyses For 8/15/79 All Power Reactor (Sucolerent) As-Built Safety-Related Facilities with Pipina Systens an OL or'a CP
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