ML18036B296
| ML18036B296 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/17/1993 |
| From: | Zeringue O TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9305250231 | |
| Download: ML18036B296 (14) | |
Text
ACCEI ERAT DOCUMENT DIST UTION SYSTEM REGULAT r INFORMATION DISTRIBUTION YSTEM
( RIDS )
ACCESSION NBR:9305250231 DOC.DATE: 93/05/17 NOTARIZED: NO DOCKET FACIL:50"260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 AUT'H.NAME AUTHOR AFFILIATION ZERINGUE,O.J.
Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Requests enforcement discretion from TS requirement 3.5.B.9 for RHR sys LPCI
!! containment cooling in order to repair div 2
RHR sys inboard injection valve. Proposed NSHC environ consideration encl.
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TITLE: TVA Facilities Routine Correspondence NOTES:
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D TOTAL NUMBER OF COPIES REQUIRED:
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Tennessee Valley Authority, Post Office Box 2000, Oecatur, Alabama 35609-2000 ne i'l 1~9~
O. J. "Ike" Zeringue Vice President, Browns Ferry Nuclear Plant U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter Of
)
Tennessee Valley Authority
)
Docket No. 50-260 BROWNS FERRY NUCLEAR PLANT (BFN) - UNIT 2 REQUEST FOR ENFORCEMENT DZSCRETION FOR RESIDUAL HEAT REMOVAL SYSTEM (RHRS)
LOW PRESSURE COOLANT INJECTION (LPCZ)
AND CONTAINMENT COOLING TECHNICAL SPECIFICATION (TS)
REQUIREMENT 3.5.B.9 On May 17, 1993, with BFN Unit 2 in the cold shutdown condition with division 2
RHRS in shutdown cooling mode, the division 2 RHRS inboard injection valve failed to operate to throttle flow.
This condition makes the valve inoperable for LPCI mode.
In order to repair the valve, division 2
RHRS must be secured and division 1 RHRS will need to be aligned in the shutdown cooling (SDC) mode.
Division 1 RHRS is currently in standby readiness for LPCI and containment cooling mode functions.
Moderator temperature is expected to rise 3-4 degrees per hour without SDC in service.
Since the repairs are projected to take about 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br /> and moderator temperature is about 130 degrees, repairs could not be completed before exceeding cold shutdown conditions.
Primary containment is not operable at this time.
The Unit 2 drywell head is installed.
P.40030 9305250231 930517
'PDR ADOCK 05000260 P
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U.S. Nuclear Regulatory Commission gy i7 1993 The BFN TS does not explicitly recognize the manual realignment of the RHRS from Shutdown Cooling to LPCI mode as acceptable for satisfying TS 3.5.B.9.
TVA submitted a
request for amendment to TS (TVA-BFN-TS-328) on December 23, 1992.
This amendment is pending completion of NRC review, which cannot be completed in time to support operational needs.
Therefore, in order to effect repairs in the safest manner possible, enforcement discretion is needed.
During the repair activities both Core Spray loops will be maintained operable, affording approximately 12,500 gal/min makeup water for automatic injection.
The RHR loop in shutdown cooling will maintain the capability to be manually realigned and inject in the LPCI mode.
Plant operators are currently trained and have procedures which provide for realignment of the RHRS from Shutdown Cooling to LPCI configuration.
Plant operators will be rebriefed on the aforementioned procedures prior to utilizing the enforcement discretion.
The intent of TS 3.6.B.9 is to ensure that, at atmospheric
- pressure, at least one supply of makeup water is available to the core.
Requiring two operable RHR pumps and one operable Core Spray System pump, per TS 3.5.A.4, ensure this redundancy.
The safety design basis for the RHRS is that it will-operable automatically except when in the Shutdown Cooling Mode.
In the event of a postulated inadvertent vessel draindown, because of low pressure and low temperature conditions in the Cold Shutdown mode, sufficient time will be available to manually align and initiate LPCI to provide core cooling prior to postulated core uncovery.
Additional margin is assured because both core spray loops will be maintained operable.
The maintenance and repair activities necessitating this request will be needed only during, the repair of components in the affected LPCI loop.
This repair activity is expected to last 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br />.
TVA has submitted a formal request for change to the TS referenced above.
The permanent change will clearly identify the need for LPCI availability and capability in Cold Shutdown.
Ck II
U.S. Nuclear Regulatory Commission ev 1 7 1993 Pursuant to NRC guidance for enforcement discretion, the Plant Operations Review Committee (PORC) has reviewed and approved the activity under discretionary enforcement.
The requested action is viewed to have no safety significance because LPCI can be realigned manually from,the RHR Shutdown cooling mode in an adequate time frame to ensure core cooling requirements for the Cold Shutdown condition along with both operable Core Spray loops.
For this reason TVA has determined that this proposed request will not involve a significant increase in the probability or consequences of accident previously evaluatedg or create the possibility of a new or different kind of acciden't from an accident previously evaluatedg or involve a significant reduction in a margin of safety.
The Proposed No Significant Hazards Consideration is enclosed.
'Further, this proposed change does not involve any adverse environmental consequences.,
TVA, therefore, requests enforcement discretion from the requirement that at least one RHR loop wi.th two pumps or two loops with one pump per loop be operable when the reactor vessel pressure is atmospheric and irradiated fuel is in the vessel (TS 3.5.B.9).
As a compensatory
- action, TVA will maintain an RHR loop in SDC mode which would be operable for LPCI except for being aligned to SDC mode.
Thi's enforcement discretion is needed from the time that RHRS loop 1 is placed in SDC mode until RHRS, loop 2 can be: made operable for LPCI mode.
The expected duration is 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br />.
Sincerely,
- 0. Z. Zeringue Enclosure cc:
See page 2
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U.S. Nuclear Regulatory Commission NY iV l393 Enclosure cc (Enclosure):
NRC Resident Inspector Browns Ferry, Nuclear Plant Route 12, Box 637'thens,,Alabama 35611 Mr. Thierry M. Ross, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 'Rockville Pike Rockville, Maryland 20852 U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
I, A'
ENCLOSURE Pro osed No Si nificant Hazards Consideration The NRC has promulgated standards in 10 CFR 50.92(c) for determini.ng whether a proposed amendment to a facility operating license involves no significant hazards, consideration.
A discussion of each of the three standards follows for the proposed enforcement discretion for Technical Specifications (TSs):3.5.B.9:
1.
This enforcement discretion does not involve a significant increase in the probability or consequences of an accident previously evaluated.,
The probability of a previously evaluated accident is not increased because no new accident precursors are introduced, no new operating modes are established and no significant procedure changes are.to be promulgated'.
The consequences of a previously analyzed accident are not increased because adequate core cooling will be assured for two reasons:
a.
Low Pressure Coolant Injection (L'PCI)'an be aligned in time to perform. its function considering current residual heat loads.
b.
This change does not change the Core Spray availability requirements in TSs.
2.
This enforcement discretion does not create the possibility of an accident of a new or different kind than previously evaluated.
There have been no. new plant configuration or failure modes introduced.
3.
This enforcement discretion does not significantly reduce the margin of safety.
The time frame for responding to a requ'irement for LPCI injection is sufficient for manual operator actions to provide this function so that the fuel temperature does. not exceed'esign limits.
Additionally, other safety limits are not potentially comprised.
1>
ENCLOSURE (Continued)
Environmental Consideration The proposed enforcement discretion has been reviewed against the criteria of 10 CFR 51.22 for environmental considerations.
The proposed change does not involve a significant hazards consideration, nor increase the types and amounts of effluents that may be released offsite, nor significantly increase individual or cumulative occupational radiation exposures.
- Thus, the proposed enforcement discretion meets
.the criteria for categorical exclusion from the requirement for an environmental
,impact statement..
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