ML20100M506
| ML20100M506 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 12/06/1984 |
| From: | Harrington W BOSTON EDISON CO. |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| 84-204, GL-84-09, GL-84-9, NUDOCS 8412120348 | |
| Download: ML20100M506 (2) | |
Text
I
,4s' BOSTON EDISON COMPANY 500 BovLaTcN STREET BoaTON. MABBACHUBETTE D2199 December 6, *;34 WILLIAM D. HARRINGTON a..............,
BEco 84-204 ra==
Mr. Darrell G. Eisenhut, Director Division of Licensing Of fice of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C.
20555 License DPR-35 Docket 50-293 Pilorim Station Conformance to Generic Letter 84-09
Dear Sir:
Boston Edison Company (BECo) has completed a plant specific examination through the BWR Owner's Group to ensure applicability to Dilgrim Station of the generic studies submitted by the Mark I Owner's Group.
The "NUSCO Analysis" addresses NRC's concern over the potentially adverse ef fect of coolant impur'ty on radiolytic oxygen generation. The limiting iodine concentration above which radiolysis is a concern has been calculated
~ for Pilgrim Station.
The result of this analyt.is demonstrates that the post-design basis accident primary coolant iodine concentrations predicted, using conservative Appendix K models, is significantly less than the critical
. iodine concentration which would cause radiolysis to be a concern for the generation of combustible gases.
The following information is provided in response to the criteria enumerated in Generic letter 84-09:
- 1) A Technical Specification change has been initiated (BEco Letter 84-203 to NRC dated December 6,1984) to maintain the concentration in containment at less than 4% oxygen.
- 2) The plant has nitrogen for use in all pneumatic control systems in containment along with instrument air capability as a backup. Pilgrim Station has no r3 cycled containment atmosphere.
- 3) A review was conducted, in conjunction with Pilgrim Station technical staff personnel, to ascertain potential sources of inleakage of air and oxygen into containment.
During normal operation, the only possible source of inleakage is from the instrument air system at the tie between the nitrogen and air systems.
In the event of loss of drywell instr ument nitrogen supply, instrument air would be utilized until the containiaent oxygen content reaches 4%, or_ the plant would be shut down within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The nitrogen system has been upgraded during this current outage to concur with NRC requirements.
(IE Bulletin 80-25, 12/19/80)
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8412120348 841206 PDR ADOCK 05000293 P
u.-
mosTON ' EDISON COMPANY Mr.-Darrell G. Eisenhut, Director
-Page'.2 For accident conditions, Pilgrim has a seismically-designed, emergency nitrogen makeup line with the capability of accepting nitrogen delivered from an offsite source should the circumstance dictate its use. This alternate source may be utilized to maintain the oxygen content below 4% by volume inside containment under post-accident conditions.
Appropriate guidance for the management of combustible gases uader all accident scenarios will be a component of the BWR Owner's Group Emergency Procedure Guidelines (EPG's, Rev. 4).
Plant specific procedures based upon this guidance will be implemented following NRC approval of the EPG's.
Based upon the criteria contained in Generic Letter 84-09, it is concluded that hydrogen recombiners are not required for PNPS.
In addition, PNPS does not rely upon a purge /repressurization system as the primary means of hydrogen control.
Please contact us if further information on this issue is required.
Very truly yours.
M ERM/ns 0
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