ML19329E620
| ML19329E620 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry, Midland  |
| Issue date: | 04/03/1975 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Howell S CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 8006160401 | |
| Download: ML19329E620 (1) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION REGION lll 799 ROOSEVELT ROAD GLEN ELLYN, ILLINOIS 60137 April 3, 1975 i
Coastaaers Power Company Docket No. 50-329 /
1 ATTN Mr. Stephen H. Howell Docket No. 50-330 Vice President 1945 West Parnall Road Jackson, Michigan 49201 Gene 1===a:
Enclosed are TE Bu11stina No. 75-04 and No.75-04A which are forwarded to you for information.
Should you have questions regarding these Bulletins, please contact this office.
Sincerely yours.
James G. Keppler Regional Director
Enclosures:
IB Bu11stine No. 75-04 and No.75-04A F
THIS DOCUMENT CONTAINS bec: Central Files
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n April 3, 1975 IE Bulletin No. 75-04 CABLE FIRE AT BROWNS FERRY NUCLEAR POWER STATION DESCRIPTION OF CIRCUMSTANCES:
Preliminary information from Tennessee Valley Authority regarding a fire which occurred on March 22, 1975, at their Browns Ferry site near Athens, Alabama, indicates that the fire was started as a result of construction activities. The fire resulted in the shutdown of two operating nuclear plants and made several safety systems inoperative, including systems normally used for decay heat removal during shutdown.
The workmen were engaged in construction activitics on a third unit not yet licensed for operation by NRC.
Initial information indicates that during the installation and testing of cable through-wall penetrations an open flame ignited a flammable material used in the penetration seals.
ACTION TO BE TAKEN BY LICENSEES:
The following actions are reque ad of sc1ceted Licensees with operating power reactor facilitics and me,ar construction activitics at a common site:
1.
Review your overall procedurcs and system for controlling construction activities that interface with reactor operating activitics, with particular attention to the installation and testing of seals for electrical cables between compartments of the reactor building, e.g.,
control room to cable spreading room.
2.
Review the design of floor and wall penetration seals, with particular attention to the flammability of materials.
3.
Evaluate your procedures for the control of ignition sources which may be used for leak testing or other purposes in areas containing flammabic materials.
4.
Report to this office, in writing within 20 days of the date of this Bulletin, the results of your reviews or evaluations regarding items 1 through 3 above.
ACTIONS TO BF. TAKEN BY LICENSEES MAY BE REVISED:
The acti~ons requested of Licensecs above may be revised as additional details of the Browns Ferry occurrence are available and evaluated by the NRC.
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April 3, 1975 IE Bulletin No.75-04A.
CABLE FIRE AT BROWNS FERRY NUCLEAR PLANT' The following material supplements and modifies IE Bulletin 75-04 DESCRIPTION OF CIRCUMSTANCES Additional, though still preliminary, information has become available related to the fire which occurred at the Browns Ferry Site on March 22, 1975. The fire started in the cable spreading room at a cabic penetration through the wall between the. cable spreading room and the reactor building for Unit 1.
A slight differential pressure is maintained (by design) across this wall, with the higher pressure being on the cable spreading room side. The penetration seal originally present had been breached to install additional cables required by a design modification.
Site personnel were resealing the penetration after cable installation and were checking the airflow through a temporary seal with a candle flame prior to installing the permanent sealing material. The temporary sealing material was highly combustible, and caught fire.
Efforts were made by the workers to extinguish the fire at its origin, but they apparently did not recognize that the fire, under the influence of the draf t through the penetration, was spreading on the reactor building side of the wall. The extant of the fire in the cable spreading room was limited to a few feet from the penetration; however, the presence of the fire on the other side of the wall from the point of ignition was not recognized until significant damage to cables related to the control o'f Units 1 and 2 had occurred.
Although control circuits for'many of the systems which could be used for Unit I were ultimately disabled by the fire, the station operating personnel were able to institute alternative measures by which the primary system could be depressurized and adequate cooling water supplied to the reactor vessel. Unit I was shut down manually and cooled using remote manual relief valve operation and condensate booster pump, and control rod drive system pumps.' Unit 2 was shut down and cooled for the first hour by the RCIC. After depressurization, Unit 2 was placed in the RHR shutdown cooling mode with makeup water available from the condensate booster pump and control rod drive system pump.
ADDITIONAL ACTIONS TO BE TAKEN HY LICENSEES-1.
Because the occurrence appears to have resulted from modifications being made to an operating unit, all power reactors with operating licenses should address the actions requested in Bulletin 75-04 as well as the' actions' described below.
2.
Review yourlpolicies and procedures relating to construction or maintenance and modification work to assure that activities which
<jy might affect the safety of a unit in operation, including the F'
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's IE Bulletin No.75-04A April 3, 1975 ability to shut down and cool the unit are properly controlled. Your review should consider particularly your policy on deferring construction, maintenance or modification work on a unit until a shutdown period except for emergency maintenance vital to continued safe operation or safe shutdown of the unit.
3.
Review your policies and procedures to assure that for construction or modification and maintenance activities during plant operation, particular attention is given to the following areas:
a.
The degree of safety significance of affected and nearby cabling and piping.
b.
The use and control of combustible materials.
c.
The use and control of equipment that may be an ignition source.
d.
The assignment of personnel, knowledgeable of plant arrangement and plant operations, whose sole temporary responsibility is conitoring the safe performance of construction or maintenance and modification work, including attention to otherwise unattended areas adjacent to the work arean, e.
Provision of installed or portable equipment to provide the monitoring personnel with prompt communication with the operating staff in the control room.
f.
Prevision of adequate fire prevention and fire suppression equipment, installed or portable, for'the following locations:
(1) Areas where work is being performed.
(2) Areas where occurrence of a fire has high safety significance, even though the probability of occurrence is relatively small.
g.
Recognition' that a fire, even one involving electrical equipment, may, if of sufficient intensity require water as the ultimate suppression medium.
4.
Review your emergency precedures to assure that consideration for alternate methods for accomplishing an crderly plant shutdown and cooldown are provided in case of loss of ~ normal and preferred alternative shutdown and cooldown systems for any reason (e.g.. a flyc).
In this connection, assure that the minimum 4
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... a IE Bulletin No.75-04A April 3, 1975 information necessary to assist the operators in such shutdown actions, the minimum protection system actions required (e.g.,
scram) and the spectrum of alternative paths available to the operators to supply cooling water and remove decay heat dependent on plant conditions are included in your emergency procedures.
5.
Report to this office, in writing, within 20 days of the date of this Bulletin, your schedule for review.in each of the above areas.
6.
Upon completion of your reviews, provide this office with the results of these reviews and the schedule for accomplishment of any revisions to your policies and procedures, and any proposed changes to the facility, and the date by which the changes are scheduled to
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be completed. If this latter date is more than 30 days after the date of the initial report, provide a monthly summary report detail-ing your progress in the review and/or proposed procedure or facility modifications. Reports requested by Bulletin No. 75-04 may be incorporated with the initial response to this Bulletin.
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