ML20042F740

Responds to Generic Ltr 89-19, Request for Action Re Resolution of USI A-47, 'Safety Implication of Control Sys in LWR Nuclear Power Plants.' TVA Will Finalize Calculations for Switch Setpoints Prior to Units Restart

ML20042F740
Person / Time
Site:	Browns Ferry
Issue date:	05/04/1990
From:	Wallace E TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-GTECI-A-47, REF-GTECI-SY, RTR-NUREG-1217, RTR-NUREG-1218, TASK-A-47, TASK-OR GL-89-19, NUDOCS 9005090328
Download: ML20042F740 (5)

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ETENNETSEE VALLEY AUTHORITY .',

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,. CHATTANOOG A. TENNESSCE 37401 l SN 1578 Lookout Plate ,

T y MAY 04 B90' a

Q U.S. Nuclear Regulatory Commission

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ATTN: ' Document Control Desk n

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Washington, D.C. 20555:

W = Gentlemen:

b LIn:the Hatter.of. ) Docket Nos. 50-239 iTennessee Valley Authority ) 50-260 1 50-296

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' BROWNS;FERRYNUCLEARPLA'T'(BFN)-RESPONSETOGENERICLETTEk89-19-REQUEST N

FOR ACTION' ret.ATED.TO. RESOLUTION Of UNRESOLVED SAFETY. ISSUE A-47 " SAFETY IMPLICATION OF CONTROL- SYSTEMS U LWR NUCLEAR POWER PLANTS" The. subject generic letter requested licensees / applicants ~to implement the ;i

recommendations' contained-in NUREG-1217. Evaluation of Safety Implications of

Control Systems in Light' Water. Reactor Nuclear Power Plants" and NUREG-1218, y '

" Regulatory Analysis for-Resolution of USI A-47" in order to enhance safety.

? Specifically, the recommendations for Boiling Water Reactor plants, included:

F ^i.; .Providing' automatic! reactor vessel overfill protection system that is

.sufficiently separate from the control portion of the main feedwater <

control. system,

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,?2.- . Incorporate appropriate changes to plant procedures and technical specificati_ons to lnclude requirements for periodically verifying  ;

R > operability of the system. The system design and setpoints should be 'l selected with the objective of minimizing inadvertent trips of the main

'r feedwater system during plant startup, norrrF operation, and protection

. system surveillance.

.w r .-3. Reassess operating ;.rocedures and training to ensure that overfill events that may occur via the-condensate booster pumps during reduced pressure

operation can be mitigated, o LTVA1has been working with and providing information-to the Bolling Water

,  ? Reactor Owners' Group (BHROG) and hereby endorses their April 4, 1990 generic

response to the subject GL. BHROG's generic responsa addresses NRC's K recommended modificattor,; to affected systems. This submittal provides TVA's K' site. specific response, which addresses BFN's cur rent automatic overfill

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protection system, and NRC's piocedural, technical specification, and tralning recommendations.

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h.; An Equal onportunity Employer e a' '

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T W ' U.S. Nuclear Regulatory Commission MAT 01 m L' Enclosure.1.contains BfN is response to each of these recommendations.

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Enclosure 2 provides the commitment contained in this submittal. '

U-If you have any questions, please telephone Patrick P. Carter, BfN Site Lic.ensing,-(205) 729-3570.

b Very truly yours, y TENNESSEE VALLEY AUTHORITY l

E. G. Hallace, an 0

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Nuclear Licensing and Regulatory Affairs q Enclosures

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.Ms. S. C. Black, Assistant Director 5

'for Projects .j TVA Projects Division '!

U.S. Nuclear Regulatory Commission  !

One White flint, North l 11555 Rockville Pike 1 Rockville,. Maryland 20852  !

NRC Resident Inspector- i Browns ferry Nuclear Plant  !

-Route 12, Box 637 .j

' Athens,. Alabama 35609-2000 . ,,  !

Mr. B. A. Wilson, Assistant-Director j for Inspection Programs-TVA Projects Division  :

U.S. Nuclear Regulatory Commission l E . Region II i 101 Marietta Street, NW, Suite 2900 '

Atlanta, Georgia 30323 i

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ENCLOSURE 1

,i TVA RESPONSE TO GENERIC LETTER (GL) 89-19 FOR BROHNS FERRY NUCLEAR PLANT (BFN) UNITS 1, 2, & 3 l

REFERENCE:

" Proposed Policy Statement on Techq1 cal.Specift:ation Irprovements for Nuclear Power Reactors," Nuclear Regulatory

.m -Commissions, Federal Register, Volume 52, No. 25, February 6', 1987.

ACTION 1: Provide an automatic reactor vessel overf111 protection system-

.that is.sufficiently separate from the control portion of the main feedwater control system.

TVA RESPONSE:

A review has been performed on'the adequacy of BFN's automatic overfill. .

protection system for compliance with the recommendations set forth in'the GL. It was determined that in accordance with the grouping categorizations defined in enclosure 2 of the subject GL, BFN's automatic overfill protection system (2-out-of-3 trip logic) f alls in Group I. BFN's overfill pro _tection system has separate power supplies; however, the relays for all 3 channels are located in the same cabinet.

TVA endorses BWR Owners Group's April 4, 1990 generic response to the subject

=GL,'which addresses NRC's recommended modifications to affected systems.

Specifically, TVA concurs with BHROG's assessment that the cost to provide.

additional independence, to fully implement the GL 89-19 recommendations, is substantial and the modifications are not cost beneficial.

ACTION 2: Incorporate appropriate changes to plant procedures and technical e specifications to include requirements-for periodically verifying _

operability of the system. The system design and setpoints-should be selected with the objective of minimizing inadvertent trips of_the main feedwater system during plant startup, normal operation, and protection system surveillance.

TVA RESPONSE:

BFN has calibration instructions which include provisions to verify periodically-the operability of-the overfill protection instrument channels.

The current _setpoints have been provcn to be adequate based on BFN's operating experience and preliminary engineering calculations. TVA will finalize the engineering calculations that will form the basis for the setpoints for the high vessel feedwater level switches. These calculations will be completed for units 1, 2, and 3 prior to restart of the respective units.

TVA's position regarding NRC's recommendations concerning revisions to the plant's technical specifications (TSs) is that the vessel overfill concerns do not satisfy the screening criteria prescribed in the referenced NRC proposed policy statement. Specifically, the vissel overfill event is not considered a design basis accident or transient event. Enclosure 2 to the Generic Letter recognizes this position by stating that "these concerns have not been addressed in a number of piant designs, because overfill transients normally have not been analyzed". Thus, the RPV water level 8 feedwater trip ,

should not be added to plant TSs on the basis of the overfill event.

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-Enclosure p f - r, Page 2 b ,.A

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F . ACTION 3: Reassess l operating procedures and training to ensure that overfill-kcr events that may occur via.the: condensate booster pumps during fy, i" "; .,

, reduced pressure operation can be mitigated,

• 'TVA RESPONSE:-

h as kf$ , TVAhasasse'ssedIFNoperatt'ngproceduresconcerningLmitigatingoverfill JL events causediby.the: condensate-booster. pumps during reduced pressure' - . ,

m Joperation;. TVA has.; determined that-BfN' procedures-. fulfill-the requirements

that would al. low operatorsL_to mitigate theiconsequences of an' overfill '

event.- This procedure has been placed in' the required: operator readingz :l

, Jpackage, to' stress the importance of! mitigating an overfill event ; ,

Additionally, overfill concerns are addressed in the 11nitiali class. room phase

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lof the hot 1icense training.and;in'the simulator. phase:of:the.requalification-

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Enclosure 2

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'i COMMITMENT,

SUMMARY

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s TVA wills finalize the engineering calculations that will form the basis for l

. the setpoint for the high vessel feedwater level: switches. .These. .

l calculations will be completed for units 1, 2, and 3 prior.to restart of the

, respective units. R t

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