ML19341A853
| ML19341A853 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 01/05/1981 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEB-80-24, NUDOCS 8101280505 | |
| Download: ML19341A853 (5) | |
Text
Tessesse) VALLEY AUTHORITY
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CH ATTANOOG A. T ENNFSS EE 37101
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400r Chestnut Street Tower II l Jm M nE: 53
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8 January 5, 1981 og u'#' d' O b
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l-Mr. James P. O'Reilly, Director C
Office of Inspection and Enforcement A '[7 U.S. Nuclear Regulatory Ccmnission h
R Region II - Suite 3100 4/g fg 101 Marietta Street g
Atlanta, Georgia 30303
Dear Mr. O'Reilly:
TFICE OF INSPECTICN AND E'f0RCDENT RTrmIN 80 RII:JPO 50-259, -260, -296 - BMJWNS FERRY NUCLEAR PLANT Your letter dated November 21, 1980, to H. G. Parris transmitted IE Bulletin 80-24 for TVA action. Enr:losed are the results of our investigations for the Browns Ferry Nuclear Plant.
If you have any questions, please call Jim Dcaner at FTS 857-2014.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, er Nuclear Regulation and Safety Subscribed and sworn to before me this V 't day of / /,'<o.
1981.
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fDbsn.5 $'. kit <u Lv1 Notary Public My Cmmission Expires YZ Enclosure cc: Office of Inspection and Enforcement (Enclosure)
U.S. Nuclear Regulatory Ca mission Division of Reactor Operations Inspection Washington, DC 20555 8]O 12805%
An Ecual cpportunity Employer
DCDSURE RESPCNSE TO OIE BULIETIN 80-24 DATED NOVEMBER 21, 1980 BROWNS FERRY NUCLEAR PLANT (50-259, -260, -296)
The Browns Ferry Nuclear Plant (BEN) has no open cooling water systems inside contaiment. At BFW units 1, 2, and 3, cmponents inside contaiment which require supp1 mental cooling are cooled by the reactor building closed cooling water (RBCCW) system (IVA systen number 70). These cmponents inside contaiment (units 1, 2, and 3) are:
1.
Drywell equipnent stmp heat exchanger 2.
Peactor water recirculation pump and motor coolers (2 pump coolers and 2 motor coolers) 3.
Drywell atmosphere cooling coils (10 individual cooling coils)
Paragraph 3 of " Actions to be Taken by Licensees" requires that plants with closed cooling water systens inside contalment provide a sumary of experiences with cooling water system leakage into contaiment. To cunply with this request, two methods were used.
The first method consisted of a search of the plant material history files for any maintenance performed on the cmponents listed above.
Maintenance that was done on the cmponents which might involve leakage was recorded and listed for review. The second method used was to record all incidents where the unidentified leakage of coolant into containment exceeded the specified limit. BEN technical specification 3.6 states that unidentified leakage shall not exceed five gallons per minute (gal / min). Each time this limit was exceeded during the operation of units 1, 2, and 3, a Licensee Event Report (LER) was issued, the source of the leakage determined, and the situation resolved. The BEN LER's which involved leakage are listed and included for review in this report. A brief systen description and the sumary of maintenance history and leakage LER's are included in Attachment A for your review.
Approximately three man-weeks were expended in review and preparation of the response for the subject bulletic.
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l ATTACHMENT A The reactor building closed cooling water (RBCCW) system provides a heat sink for the following equipment within the primary containment:
drywell atmosphere cooling coils (10 per unit), drywell equipment sump heat exchanger (1 per unit), and seals and bearings of the reactor recirculatien pumps '(two per unit). The RBCCW cystem recirculates demineralined water r ecated with sudium nitrite,and sodium hydroxide. The level of water in the syntem is monitored by instruments attached to a surge tank, An alarm is annunciated in the control room when thc level in the surge tank becomes low.
Additional details concerning the RSCCW system can be found in section 10,6 of the BFN Final Safety Analysis Report.
A review of maintenance records revealed only three cases of RECCW leakage within primary containment.
In August of 1973, a piping joint on a unit 1 drywell cooler had to be resoldered. During the 1980 unit I refueling outage, a fatigue crack was found in a line to the recirculation pump motor bearing oil cooler. During the 1980 unit.
2 refueling outage, a small leak (drip) was found on a line to the A5 drywell atmosphere cooler.
Positive displacement control rod drive hydraulic pumps are used to supply condensate to operate and cool the control rod drives (CRD).
These pumps are located outside the prim: fry containment,but system piping and valves are located within the primary containment.
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The pumps tale suction from the primary cycle (condensate storage tank) and the water is discharged back into the primary cycle thus creating a closed loop.
A review of maintenance records revealed that only very minor leaks (drips) have been experienced with the CRD system components within primary containment. These minor leaks have occurred at the control drive to reactor vessel flanges.
These Icaks are visible during cold hydrostatic testing of the vessel and disappear when the vessel reachec rated temperature cud pressure.
Leakage f rom the R!:CCW and CRD systems inside the primary containment would accumulate in the drywell floor drain sump. This sump is designed to handic and quantitatively monitor the total leakage within the primary containment. BFN Technical Specifications Sections 3.6/4.6,respectively, limit the unidentified leakage rate to 5 gal / min and require daily quantitative determination of this leakage rate. Therefore, assuming l
no other sources of unidentified leakage, the leakage rate inside the primary. containment from the RBCCW and/or CRD systems is limited by I
technical specifications to less than 5 gal / min.
1 l
A review of licensee event reports (LER) revealed that the unidentified leakage rate of 5 gal / min has been exceeded only ence on each unit.
l Neither the RBCCW or the CRD system were responsible for causing l
l any of these LER's.
Specific details on each instance are listed i
below:
1
. lini t 1 BFR0 259/7826 - Caused by a bonnet leak on FCV-68-77 (recirculation l
system) and a packing leak on FCV-69-1 (rcactor
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water clean-up system)
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,,J Unit 2.IIFR0 260/ 7805 - Caused by a packing leak on FCV-68-33 (recirculation system)
Unit 3 BFR0 296/7319 - Caused by partial broken wcld on a 1-inch socket weld fitting en a jet pump riser instru.m.cnt scusing line.
- Nis.PS