ML19256F420
| ML19256F420 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 11/30/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| References | |
| NUDOCS 7912190118 | |
| Download: ML19256F420 (1) | |
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UNITED STATES lD 8"'.
NUCLEAR REGULATORY COMMISSION o
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REGION V o,
1990 N. CALIFORNIA BOULEVARD U
o SUITE 202, WALNUT CREEK PLAZA WALNUT CREEK, CALIFORNIA 94596 November 30, 1979 Docket Nos. 50-528, 50-529 50-530 Arizona Public Service Company P. O. Box 21666 Phoenix, Arizona 83036 Attention: Mr. E. E. Van Brunt, Jr.
Vice President, Construction Projects Gentlemen:
The enclosed IE Bulletin No. 79-27 is forwarded to you for information.
Although no written response is required at this time, these concerns will be addressed as part of the licensing process for your plant.
If you desire additional information regarding this matter, please contact this office.
Sincerely,
[ [f[5cifs---
R. H. Engelken Director
Enclosures:
1.
Recently Issued IE Bulletins cc w/ enclosures:
F. W. Hartley, APS 1619 352 7912190/ /$
T UNITED STATES SSINS No.: 6820 NUCLEAR REGl'LATORY COMf11SSION Accession ?!o.:
OFFICE OF INSPECTION AND ENFORCEMENT 7910250499 WASHINGTON, D.C.
20555 November 30, 1979 IE Rulletin No. 79-27 LOSS OF NON-CLASS-1-E INSTRUMENTATION AND CONTROL on'lER SYSTEM BUS DURING OPERATION Descrintion of Circumstances:
On November 10, 1979, an event occurred at the Oconee Power Station, Unit 3, that resulted in loss of oower to a non-class-1 F 120 Vac sincle phase power panel that supplied oower to the Integrated Control System (ICS) and the Non-Nuclear Instrumentation (f!NI) Systen. This loss of power resulted in control system malfunctions and significant loss of information to the control room operator.
Specifically, at 3:16 o.m., with Unit 3 at 100 cercent power, the main condensate pumps tripoed, aoparently as a result of a technician perfoming 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 oower supply feeding all cower to the integrated control system (which provides procer 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 triooed due to blown fuses.
Loss of power to the NUI rendered control room indicators and recorders for the reactor coolant systen (except for one wide-rance RCS pressure recorder) and nost of the secondary olant systems inoperable, causino loss of indication for systems used for decay heat renoval and water addition to the reactor vessel and stean generators. Upon loss of oower, all valves controlled by the ICS assumed their resoective failure positions.
The loss of oower existed for anproximately three minutes, until an operator could reach the eauionent roon 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 "Investication into the March 28, 1979 TMI fccident" also discusses TMI LEP, 78-021-03L whereby the oCS donressurized 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 operating license and for those nearing completion of construction (North Anna 2, Giablo Canyon, McGuire, Salen 2, Seouoyah, and Zimmer):
1619 353
IE Bulletin tio. 79-27 tiovember 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 achieve 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 the bus.
b) identify the ir.strument 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 from these reviews and evaluations, and your proposed schedule for implementing 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 povier to safety and non-safety related instrument and control systems. The emergency procedures should include:
a) the diagnostics / alarms / indicators / symptom resulting from tne 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 flo. 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 t1RC Regional Office and a copy should be forwarded to the ftRC Office of Inspection and Enforcement, Division of Reactor Operations Inspection, Washington, D.C.
20555.
If you desire additional information regarding this matter, please contact the IE Regional Office.
Approved by GA0 B180225 (R0072); clearance expires 7/31/80.
Approval was given under a blanket clearance specifically for identified generic problems.
1619 354
9 IE Bulletin No. 79-27 Enclosure Novebner 30, 1979 RECENTLY ISSUED IE BULLETINS Bulletin Subject Date Issued Issued To No.
79-26 Boron Loss Fron B'M 11/20/79 All BNR power reactor Control Blades facilities with an OL 79-25 Failures of Vestinghouse 11/2/79 All onwer reactor BF0 Relays In Safety Pelated facilities with an Systems OL or CP 79-17 Pipe Cracks In Stagnant 10/29/79 All PPR's with an (Rev. 1)
Borated Water System At OL and for information PWR Plants to other oower reactors 79-24 Frozen Lines 9/27/79 All power reactor facilities which have either OLs or cps and are in the late stage of construction 79-23 Potential Failure of 9/12/79 All Power Reactor Emergency Diesel Facilities with an Generator Field Operatina License or Exciter Transformer a construction permit 79-14 Seismic Analyses For 9/7/79 All Power Reactor (Suoplement2)
As-Built Safety-Related Facilities with an Pioing Systems OL or a CP 79-22 Possible Leakaqe of Tubes 9/5/79 To Each Licensee of Tritium Gas in Time-who Receives Tubes pieces for Luminosity of Tritium Gas Used in Timepieces for Luninosity 79-13 Cracking in Feedwater 8/30/79 All Desiqnated (Rev. 1)
System Piping Applicants for OLs 79-02 Pipe Support Base Plate 8/20/79 All nower Reactor (Rev. 1)
Designs Usino Concrete Facilities with an (Suopienent 1)
Exoansion Anchor Bolts OL or a CP 79-14 Seismic Analyses For 8/15/79 All Power Reactor (Suoplement) As-Built Safety-Related Facilities with Pipinq Systens an OL or a CP 1619 355