ML19295C009
| ML19295C009 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities, Zion  |
| Issue date: | 04/03/1975 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Brian Lee COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8010150709 | |
| Download: ML19295C009 (1) | |
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4 UNITED STATES NUCLEAR REGULATORY COMMISSIOh
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C - uaualth Edison Company Docket No. 50-10 ATIN:
Mr. Byron Lee, Jr.
Docket No. 50-237 Vice President Docket No. 50-249 P. O. Box 767 Dockat No. 50-254 Chicago, Illinois 60690 Docket No. 50-265 Dockat No. 50-295 Dockat No. 50-304 Gentle:aen:
Enclosed are IE Bullatins No. 75-04 and No.75-04A vhich requira action by you with agard to your power reactor facilities with an operating licensa.
Should you have questions regarding these Bulletina or the actions required of you, plaase centact this office.
Sincerely, p'()y James G. 7.eppler Regional Director Enclosuras:
IE Bulletina No. 75-04 and No.75-04A Approved by GAO, 3-180225 (RC072), clearance expires 7/31/77. Approval vae given under a h' rat clearance specifically for identified generic problems.
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April 3, 1975 IE Bulletin No. 75-04 CABLE FIRE AT BROWNS FERRY NUCLEAR POWER STATION DESCRIPTION OF CIRCUMSTANCES:
Preliminary information f rom 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 shutdcwn.
The workmen were engaged in construction activities on a third unit not yet licensed for operation by NRC.
Initial information indicates that during the installation and testing
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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 requested f selected Licensees with operating power reactor facilities and major onstruction activities at a ccamon site:
1.
Review your overall procedures and sys, tem for controlling construction activities that interface with reactor operating activities, with particular attention to the installation and testing of seals for electrical cables between ccapartments 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 #1a=mability 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 flammable 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 BE TAKEN BY LICENSEES MAY BE REVISED:
The actions requested of Licensees above may be revised as additional details of the Browns Ferry occurrence are available and evaluated by the NRC.
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m 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 beccme available related to the fire which occurred at the Browns Ferry Site en March 22, 1975.
The fire started in the cable spreading room at a cable penetration through the wall between the cable spreading roce 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 roca 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 installatien and were checking the airflow through a temporary seal with a candle flare prior to installing the permanent sealing material.
The temporary sealing =aterial was highly ccmbustible, and caught fire.
Efforts were made by the werkers to extinguish the fire at its origin, but they apparantly did not reccgnize that the fire, under the influence of the draf t through the penetratica, was spreading on the reactor building side of the wall. The extent of the fire in the cable spreading rocm was limited to a few feet frca the penetration; however, the presence of tho fire on the other side of the wall from the point of ignition was not recognized until significanc damage to cables related to the control of Units 1 and 2 had occurred.
Although control circuits for many of the systems which could be used for Unit I were ultimately cisabled 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 rc=cte manual relief valve operation and condensate bcoster pump, and control red drive system pumps.
Unit 2 was shut down and ccoled for the first hour by the RCIC.
Af ter depressurizatien, Unit 2 was placed in the RER shutdown cooling mode with makeup water available frc= the condensate booster pump and control rod drive system pump.
ADDITIONAL ACTICNS TO BE TAKEN BY LICENSEES 1.
Because the occurrence appears to have resultedefrom modifications being made to an operating unit, all power reactors with operating licenses should address the acticns requested in 3ulletin 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 might affect the safety of a unit in operation, including the I
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m 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 cperation or safe shutdown of the unit.
3.
Review your policies and procedures to assure that for construction or modification and =aintenance activities during plant operatica, 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 ec=bustible materials.
c.
The use and control of equipment that may be an ignitica source.
The assignment of personnel, knowledgeable of plant arrangement and plant operations, whose sole temporary responsibility is monitoring the safe r*rformance of construction or maintenance and modification work, including attention to otherwise unattended areas adjacent to the work areas.
e.
Provision of installed or portable equipmen to provide the monitoring personnel with prompt communication with the operating staff in the control room.
f.
Provision 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 procedures to assure that consideration for alternate methods for accomplishing an orderly plant sh::t'"
and cooldown are provided in case of ioss of normal and preferred alternativg shutdcwn and cooldown systems for any reason (e.g., a fire).
In this connection, assure that the minimus
-m IE Bulletin No.75-04A April 3, 1975 information necessary to assist the operators in such shutdown actions, the minimum protect.on 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 acccmplishment 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 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 propcsed procedure or facility modificaticns.
Reports requested by Eulletin No. 75-04 may be incorporated with the initial response to this Eulletin.
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