ML20092C831

Suppls 920113 Application for Amends to Licenses NPF-37, NPF-66,NPF-72 & NPF-77 Requesting Changes to TS Tables 3.3-6 & 4.3-3,allowing Control Room Ventilation Sys Operation w/2 Radiation Monitors.No Significant Hazards Exist

ML20092C831
Person / Time
Site:	Byron, Braidwood
Issue date:	02/06/1992
From:	Simpkin T COMMONWEALTH EDISON CO.
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
Shared Package
ML20092C834	List: ML20092C831 ML20092C838
References
TAC-M71200, TAC-M71201, TAC-M71202, TAC-M71203, NUDOCS 9202120114
Download: ML20092C831 (5)

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.V Febmary 0,1992 Dr. Thomas E. Murloy, Director Offic,o Of Nuclear Roactor Rogulation U.S. Nuclear Rogulato Commission Washington, DC 2055a Attn: Document Control Desk

Subject:

Dyron Station Units 1 and 2 Braldwood Station Units 1 and 2 Supplomont to the application for Amendment to Facility Gporating Licensing NPF 37, NPF 00 NPF 72 and NPF 77 Appendix A. Technical Specifications TAC # M71200, M71201, M71202, M71203 HBO_ Docket Noh.50:454,50:455,.50:450 and 00:457 Reforenco: (a) November 6,1987 S.C. Hunsador letter to T.E. Murley (b) February 8,1991 A.R. Checca lottor to T.E. Murley (c) January 13 1992 T.W. Simpkin letter to T.E. Murley

. Mu'ioy:

In reference (a) Purcuant to 10 CFR 50.90, Commonwoalth Edison proposes to

\ppendix A Technical Specifications, of Facility Operating Licenso NPF 37, NPF 66, and NPF 77. The proposed amendment requests changos to Technical Specification 3.3-0 and 4.3 3, to allow the control room ventilation (VC) system to remain in Lon, providing thoro are two (2) radiation monitors operable on the ventilation train that is ag. Braldwood Unit 2 has boon licensed since the time the request was mado;

. . ore, those changes apply to Braldwood Station Unit 2, facility Operating Licenso NPF 77, as well.

Reference (b) updated the request with additional supporting Information.

Reference (c) documented minor revislons to the change roquest based on phone conversations with the NRC reviewor. The changes entall clarifications in Attachment A and C to reflect the acceptability of having two radiation monitors in a single train inoperable. The bases have boon reviewed, and no changos are requirod The Technical Specification has boon changed (Attachmont B) to incorporato a reporting roquiremont and to doloto cyclo specific rollel that is no longer applicable.

The purpose of this lotter is to amend Referenco (c) due to the revision of pago 3/4 3 42 subsequent to the original submittal. The amended page will doloto a cyclo specific rollef which is no ,onger required. Attachment C is also being revised to include wording which was inadvertently doloted

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Dr. Thomas E. Murley 2- February 6,1992 The proposed changes have boon revlowed and approved by both on sito and off sito review in accordance with Commonwealth Edison proceduros. Commonwealth Edison has reviewod this proposed amendment in accordance with 10 CFR 50.92(c) and has determinod that no significant hazards consideration exists. This ' valuation is documented in Attachment C. The original Environmental Assessment of Reference (t) tomains valid for this supplomont.

Commonwealth Edison is notifying the State of Illinois of our application for this amendment by transmitting a copy of this lottor and its attachments to the dot,lgnated Stato Official.

To the best of my knowledge and bellet the statomonts contained herein are true and correct. In some respects, those statomonts are not based on my personal knowledge but upon information recolved from other Commonwealth Edison and contractor employons. Such information has boon reviewed in accordance with Company practico and I believo it to be rollable.

Plonso direct any questions you may have concerning this mattor to this offico.

Very truly yours, O Au,,e 7d. gab T.W. Simpkin Nuclear L.lconsing Administrator Attachments (A): Revised page (9): Evaluation of Significant Hazards Consideration cc: W. Kropp-Rosident inspector, Byron S. Dupont-Rosident inspector, Braldwood NRR A, Hsia-Pro}ect R. Pulsifor Project Manager Manager (Bra (Byron)ldwood), NRR B. Clayton-Branch Chief, Rogion til Offico of Nuclear Facility Safety IDNS

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4 ATTACt%4ENT A TECHNICAL SPECIFICATION CHANGE REQUEST PHOeOSED_ CHANGES The following 18 a brief description of the changes proposed to the Byron and Braldwood, Units 1 and 2 Technical Specifications.

j Table 3.3 radiation 0 and 4.3 monitors assig3, pgs 3/4 3 40 and 4 42 respectively, are beln revised to designate the to each train of control room ventilation ( C).

Action statement 27, on page 3/4 3-41, is being revised to allow the optlun of operating a fully functional traln of VC when one (1) or more radiation monitors in the opposite VC train are Inoperable.

place the systemWith one (ESF configuration will be retained.1) or more monitors Inoperable in in its Additionally, page 3/4 3-41 for Byron and pages 3/4 3 39 and 3/4 3 41 for Braldwood are being revised to delete cycle specific reliefs which are no longer applicable. ,

DESCSIEllONDE_CURRENI.BEQUIREMENT The VC system consists of two Independent trains, each possessing 100% of the required altflow and filter capacity to ensure that the area remains habitable under postulated accident conditions. Each tialn of VC la equipped with n abysically diverse outside alt intake and a turt>ine building Intake. Each redundant train is 'ocated in a separate room. The outside air intake is the normal source of rnakeup air.

Each outside air Intake la equipped with two radiation monitors. These monitors provide an Interlock function which, upon receipt of a high radiation signal on either monitor or an operate failure signal on both monitors, will automatically align the makeup air filter unit, various

• dampers and the recirculation charcoal adsorber to the emergercy mode. The system also automatically realigns to the emergency mode on a safety injection (SI) signal.

- The Technical Specification currently requires that all fo Jr 'adiation monitors, two in each outside air Intake, be operable, in the event that a mor+ tot becomco inoperable, whichever train of VC 1s in operation is requinM to be aligned to l' i emergency configuration.

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ATTACHMENT A (Continuewf)

BASES FORJHECURRENTJiEQUIREMENT The cunent Technical Specification provides assurance that the control room operators can ,

remain inside all spaces served by the VC system for Units 1 and 2 during all normal station conditions in compilance with Criterion 19 of 10 CFR 50, Appendix A. The contr01 eoom is a common facility which serves both Units 1 and 2. Only one VC train is normally in operation with a full capacity redundant train in standby. Two radiation monitors are provided in each VC i train air Intake to detect high radiation. The VC air Intakes are at opposite ends of the auxiliary >

building. The physicallocation of the intake provides the option drawing makeup air for the control room from the less contami.iated Intake during and after a LOCA. It le possible one of the makeup air Intakes may not have any contaminan's whilo the other may have contaminants. The current specification requires a level of redundancy which ensures that the realignment of the system will be accomplished regardless of any single failure.

The accident of interest, as described in the UFSAR 6.4.4.1, page 0.411, is the large break LOCA, and it is assumed to be bounding. The radiation rnon tors associated with the outside air intakes function to align the makeup filter unit and the recirculation charcoal adsort>er in order to reduce the radiation levels in the control room to an acceptable level during accident conditions.

DESCRIPDORDE DENEED_EMAMENDINQ3HEREQUIREMENT The current requirement la overly restrictive in that it requires a VC train to be placed in its emergency configuration upon the failure of a single raolation monitor. With one or more Inoperable radiation monitors in a single VC train, a redundant full capacity VC train with a full complement of radiation monitors is still available. Sufficient redundancy is asallable such that a single failure of an additional radiation monitor can sti!I be accommodated. 4 The current requirement results in charcoal filters being placed on line for the duration of the monitor inoperability. This results in needless depletion of the charcoal capability and subsequent expenditures with no resulting safety benefit.

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ATTACHMENT A (Continued)

DASESEOR.THEAMENDEDBEQUIREMENT The amended requirement will allow 8or the operation of a VC train having its full complement of radiation monitors. The operating train of VC will be capable of realigning to the emergency mode on an SI signal, high radiation signal from either of its two (2) operable monitors or an opsrate failure signal from both of its operable monitors. When any of these initiation signals oxists the operating train of VC aligns to the emergency mode and the makeup fan starts. The standby train of VC aligns to the emergency mode on an SI signal or from inputs from its respective radiation monitors, however, the fans in the standby train do not automatically start.

These functions are not being changed; t serefore,11 the operating train should fall, manual intervention would be required to start the fans in the idle VC train.

The VC r, stem realigns to the emer e from the radiation moisitors. Thisi :ae reduc cv 'mde accidents on antoSithorn of interest signal thatwithout have thethe benefit of any input potential for a release of radioactivity wnnoat causing an Si signal. However, the proposed change only permits operation of a VC treir. !n the normal mode If both its intaka radiation monitors are operable; therefore, those accidents which result in a release of radioactivity but do not cause an SI signal are captured by the original assumptions in the accident analysis.

Tho proposed change does not render the system vulnerable to any single failure which would preclude the accomplishment of the system's design safety function.

There is significant economic benefit to be gained with the proposed change. Each filter has a limited life. Frequent operation of the charcoal filter banks during normal operations degrades the charcoal with no added safety benefit. Depletion of the charcoal would require shutdown of both units if it could not be replaced and tested within seven 7) days. The cost of replacing the charcoalin one VC train is conservatively estimated to be $4 ,000 Although no direct safety benefit can be achieved, there is no reduction in the level of protection afforded the control room Inhabitants.

SCHEDULILBEQUlBEMENIS No specific schedular rastraints have been Identified.

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