ML20067E623
| ML20067E623 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 02/08/1991 |
| From: | Checca A COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20067E624 | List: |
| References | |
| TAC-71200, TAC-71201, TAC-71202, TAC-71203, NUDOCS 9102150231 | |
| Download: ML20067E623 (4) | |
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Doun:rs Grove, ilHnois 00515 February 8,1991 Dr. Thomas E. Murley, Director Office Of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 Attn: Document Control Desk
Subject:
Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 Supplement to the application for Amendment to Facility Operating License NPF 37, NPF 66 NPF 72 and NPF-77 Appendix A, Technical Specifications TAC # 71200,71201,71202,71203 NB0]ocheLNosJiG-45L50-455m50-455_ ands 0d1EZ
Reference:
(a)
Novetaber 6,1937 S.C. Hunsader letter T.E. Murley
Dear Dr. Murley:
In reference (a) Pursuant to 10 CFR 50.90, Commonwealth Edit.on proposed to amend Appendix A Technical Specifications. of Facility Operating License NPF 37, NPF-66 and NPF 72. The proposed amendment requested 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 opstable 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.
The description and summary of the proposed changes is presented in Attachment A. The revised Technical Specification pages are contained in Attachment B.
The proposod changes have been reviewod and approved by both on-site and off-site review in accordance with Commonwealth Edison procedures. Commonwealth Edison has roviewed this pro osed amendment In accordance with 10 CFR 50.92(c) and has determined that no si nificant hazards consideration exists. This evaluation is documented in Attachment C. An E Ironmental Assessment has been completed and is contained in Attachment D.
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Dr. Thomas E. Murley 2-February 8,1991 Commonwealth Edison is notifying the State of Illinois 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 the statements contained herein are tnJe ar.d correct. In some respects, these statements are not based on my personal knowledge but upon information received from other Commonweatth 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 conceming this matter to this office.
Very truly yours, A.
Allen R. Cheoca Nuclear Licensing Administrator Attachments (A):
Description and Summary Proposed Technical Specification Changes Evaluation of Significant Hazards Consideration Environmental Assessraent Statement Sim lified Drawing-NormalOperation
,F):
Sim lified Drawing Emergency Operation i G):
Si fled Drawing-Emergency Operating (Altemate)
IH):
UF AR Section 6.4 i'l :
UFSAR Section 6.5.1 i
UFSAR Section 9.4.1 il l UFSAR Section 11.5 cc:
W. Kropp Resident inspector, Byron S. Dupont Resident inspector, Braldwood A. Hsia-Project Manager (By(ron)ldwood), NRR NRR R, Pulsifer-Project Manager Bra W. Shafer-Branch Chief, Region lil Office of Nuclear Facility Safety IDNS state oL//-
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ATTACHMENT A TECHNICAL SPECIFICATION CHANGE REQUEST PROPOSED CHANGES The following 19 a brief description of the changes proposed to the Bymn and Braldwood, Units 1 and 2, Technical Specifications.
Tables 3.3-6 and 4.3-3, pages 3/4 3-40 and 3-42 respectively, are being revised to designate the radiation monitors assigned to each traln 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.
DESRDIEIlON.OE.G_UBRENLBEQUlBEMENI The VC system consists of two independent trains, each possessing 100% of the required altflow and filter capacity to ensule that the area remains habitable under postulated accident condidans. Each train of VC ls equipped with a physically diverse outside air intake and a turbine building intake. Each redundant train is located in a separate room. The outside air intake is the normal source of makeup air.
Each outside alt 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 recirculation charcoal adsorber to the emergency mode. The system also automatically realigns to the emergency mode on a safety injection (SI) signal.
The Technical Specification currently requires that all four radiation 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.
Attached are UFSAR excerpts which provide a detalled description of the Control Room Ventilation System and the Process Radiation Monitoring System. In addition, simpilfled drawings are included which depict the system configuration in its normal and emergency lineups. The syt am is manually aligned to the alternate emergency mode if the turbine building atmosphere is unsultable.
DASES EOfLTUE.CURDENEBEOUIREMENT The current Technical Specificaton provides assurance that the control room operators can remain inside all spaces served by the VC mystem for Units 1 and 2 during all normal station conditions in compliance with Criterion 19 of iO CFR 50, Appendix A. The control room is a common facility which serves both Units 1 and P. 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 auxiliary building. The physicallocation of the intake provides the option of drawing makeup air for the control room from the less contaminated intake during end 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 accomplished 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 assurned to bo 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.
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ATTACHMENT A (Continued) o DESGillP_TK)tLOEJHENEED.f0flAMENDING_IBEREQUlREMENT The current requirement 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 Inoperable radiation monitor, a redundant full capacity VC train with a full complement of radiation monitors is still available. Sufficient redundancy is availabla that a single failure can still be accommodated with a single monitor inoperable, The current requirement results In charcoal filters being placed on line for the duration of the monitor Inowrability. This results in needless depletion of the charcoal capability and subsequenL expenditures with no resulting safety benefit.
BASES.EOfLTHEAMENDED.BEQUiMEMENT The amended requirement will allow for the operation of a VC train havin its full complomont of radiation monitors. The operating train of VC will be capable of realig g to the emergency mode on an SI signal, high radiation signal from either of its two (2) opera le monitors or an operate failure sI nal from both of its operable monitors. When any of these initiation signals D
exists the operating train of VC aligns to the emergency rnode and continues to run. The standby train of VC aligns to the emergency mode on an SI s!gnal or from inputs from its respective radiation monitors, however, the fans in the stardbv train do not automatically start.
These functions are not being changed; therefore, if the operating train should fall, manual intervention would be required to place the idle VC train in operation.
The VC system realigns to the emeroency mode on an Si signal without the benefit of any input from the radiation monitors. This reduces the accidents of intemst to those that have the potential for a release of radioactivity without causing an SI signal. However, the proposed change only permits operation of a VC train in the normal mode if both its intake radiation monitors 6a operable; therefore, those accidents which result in a release of radioactivity but do not caen an SI signal are captured by the original assumptions in the accident analysis.
The propocrd change does not ronder 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 pro)osed change. Each filter has a limited life. Frequent operation of the charcoal filter banks dur ng norms! 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 $40,000.
Although no direct safety benefit can be achieved, there is no reduction in the level of protection afforded the control room Inhabitants.
l SCHEDULE.BEQUIREMENIS No specific schedular restraints have been identified.
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