ML20087D834
| ML20087D834 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 01/13/1992 |
| From: | Simpkin T COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20087D837 | List: |
| References | |
| TAC-M71200, TAC-M71201, TAC-M71202, TAC-M71203, NUDOCS 9201170161 | |
| Download: ML20087D834 (5) | |
Text
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1400 Opus Place
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January 13,1992 Or. Thomas E. Murley, Director Office Of Nuclear Reactor Regtilation U.S. Nuclear 9egulatory Commission Washington, CC 20555 Attn: Document contro! Desk
Subject:
Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 Supplement to the application for Amendment to Facility Operating Licensing NPF-37, NPF-66 NPF i2 and NPF-77 Appendix A, Technical Specifications TAC # M71200, M71201, M71202, M71203 NRG.RockeW ot.50-454Ji0:455,_50145Eaud.50-45Z
Reference:
(a)
November 6,1987 S.C. Hunsader letter to T.E. Murley (b)
February 8,1991 A.R. Checca letter to T.E. Murley
Dear Dr. Murley:
In reference (a) Pursuant to 10 CFR 50.90, Commonwealth Edison proposes to amend Appendix A Technical Specifications, of Facility Operating License NPF-37, NPF 66, NPF-72 and NPF 77. The proposed amendment requests changes to Technical Specification Tables 3.3-6 and 4.3-3, to allow the control room ventilation (VC) system to remain in operation, providing there are two (2) radiation monitors operable on the ventilation train that is operating. Braldwood Unit 2 has been licensed since the time the request was made; therefore, these changes apply to Braldwood Station Unit 2, Facility Operating License NPF-77, as well.
- Reference (b) updated the request with additional supporting information. This letter documents minor revisions to the change request based on phone conversations with the NRO reviewer. The changes entall clarifications in Attachments A and C to reflect the acceptability
, of having two radiation monitors in a single train inoperable. The bases have been reviewed, and no changes are required. The Technical Specification Ms been changed (Attachment B) to incorporate a reporting requirement and to delete cycle specific relief that is no longer applicable.
The proposed changes have been reviewed and approved by both on-site and off-site review in accordance with Commonwealth Edison procedures. Commonwealth Edison has reviewed this proposed amendment in accordance with 10 CFR 50.92(c) and has determined that no significant hazards consideration exists. This evaluation is documented in Attachment C. The original Environmental Assessment of Reference (b) remains valid for this supplement.
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Dr. Thomas E. Murley January 13,1991 Comrnonwealth Edison is notifying the State of Iliinois of our application for this amendment by transmitting a copy of this letter and its attachments to the designated State Official.
To the best of my knowledge and belief tho statements contained herein are true and correct. In some respects, these statements are not based on my personal knowledge but upon information received from other Cominonwealth Edison and contractor employees. Such information has been reviewed in accordance with Company practice and I believe it to be reliable.
Please direct any questions you may have concerning this matter to this office.
Very truly yours, p
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? 4 jf T.W. S!mpkin Nuclear Licensing Administrator Attachments (A):
Description and Summary (B):
Proposed Technical Specification Changes (C):
Evaluation of Significant Hazards Consideration cc:
W. Kropp-Resident inspector, Byron S. Dupont-Resident inspector, Braidwood A. Hsia-Project Manager (Byron), NRR R. Pulsifer-Project Manager (Braidwood), NRP B. Clayton-Branch Chief, Region lli Office of Nuclear Facility Safety-IDNS con at 6 county of
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TT 1
ATTACHMENT A TECHNICAL SPECIFICATION CHANGE REQUEST P_BOEOSEDfeH8NGES I
The following is a brief description of the changes proposed to the Byron and Braldwood, Units 1 and 2, Technical Specifications.
Table 3.3 dend 4.3-3, pages 3/4 3 40 and 4-42 respectively, are being revised to designate the radiation monitors assigned to each train of control room ventilation (VC).
Action statement 27, on page 3/4 3-41, is being revised to allow the option of operating a fully functional train of VC when one (1) or more radiation monitors in the opposite VC train are Inoperable. With one (1) or more monitors inoperable in each train, the current requirement to place the system in its ESF configuration will be retained.
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.
DESCBlFYI1ON OF CUBBENIBraulBEMWI The VC system consists of two independent trains, each possessing 100% of the required
& Dew and fllter capacity to ensure that the area remains habitable under postulated accident conditions. Each train of VC is equipped with a physically diverse outside air intake and a turbine building intake. Each radundant train is located in a separate rnom. The outside air intake is the normal source of makoup alt.
Each outside air Intake is 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 racirculation charcoal adsorber to the emergency mude. The system also automatically realigns to the emergency mode on a pafety injection (SI) signal.
The Technical Specification currently requires that all four rad!ation monitors, two in each outside air intake, be operable. In the event that a monitor becomes inoperable, whichever train of VC is in operation is required to be aligned to its emergency configuration.
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MTACMAENT A(Congnued)
BASES EDELTHELCDHRENIBEQUIREMENI The current Technical Specification provides assurance that the control room operators can remain inside all spaces served by the VC system for Units 1 and 2 dudng all normal station conditions in compliance with Criterion 19 of 10 CFR 50, Appendix A. The control room is a common facility which serves both UnHs 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 train air intake to detect high radiation. The VC air intakes are at opposite ends of the auxillary building.' The physical location of the intake provides the option drawing makeup air for the control room from the less contaminated intake during and after a LOCA. It is possible one of the makeup air intakes may not have any contaminants while the other may have contaminants. The current specification requires a level of redundancy which ensures that the realignment of the system will be accomplisbad regardless of any single failure.
The accident of interest, as described in the UFSAR 6.4.4.1, page 6.4-11, is the large break LOCA, and it is assumed to be bounding. The radiation monitors associated with the outside air intakes function to align the makeup filter unit and the recirculation charcoal adsorber in order to reduce the radiation levels in the control room to an acceptable level during accident conditions.
DESCRIPTION OF TBEEEED FOR AMENDING THE REQUlBELINI The current requ(rement is overly restrictive in that It requires a VC train to be placed in its emergency configuration upon the failure of a single radiation monitor. With one or more Inoperable radiation monitors in a single VC traln, a redundant full capacity VC train with a full complement of radiation monitors is still availablei Sufficient redundancy is available such that a single failure of an additional radiation monitor can sti!I be accommodated.
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 (Cordinued)
BASES FOR THEAMENDED REQUIREMENI The amended requirement will allow for the operation of a VC train havin its full complement of radiation monitors. Tho operating train of VC will be capable of reall g to the emergency mode on an SI signal, high radiation signal from olther of its two (2) opera le monitors or an operate failure signal from both of its operable monitors. When any of these initiation signals exists 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; therefore, If the operating tra!n should fall, manual intervention would be required to start the fans in the idle VC train.
The VC system realigns to the emergency mode on an SI signal without the benefit of any input from the radiation monitors. This reduces the accidents of interest to those that have the potential for a release of radioactivity without causing an SI signal. However, the proposed change only permits operat!on of a VC train in the normal modo if both its intake 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.
preclude the accomplishment of the system'ystem vulnerable to any single failure wh The proposed change does not render the s 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 degrados the charcoal with no added safety benefit. Depletion of the charcoal would require shutdown of charcoalin one VC train is conservatively estimated to be $4(0,000.both units if it CoJId Although no direct safety benefit can be achieved, there is no reduction in the level of protection afforded the control room Inhabitants.
SCHEDULEBEQUIREMENIS No specific schedular restraints have been Identified.
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