ML20010F675
| ML20010F675 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 09/04/1981 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8109110144 | |
| Download: ML20010F675 (5) | |
Text
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4 PHILADELPHIA ELECTRIC CCMPANY 2301 M ARKET STREET P.O. BOX 8699 1881 -1981 PHILADELPHI A. PA.19101 (215) 841 CCC)
SHIELDS L DALTROFF ELECTatCPR cTione September 4, 1981 Re: Docket Nos. 50-277 gg,f 50-S 8
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Mr. Darrell C.
Eisenhut, Director Q
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Division of Licensing
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Nuclear Regulatory Commission dh _3 ([
Washington, DC 20555 1
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SUBJECT:
Schedule Relief for Several NRC Require Modifications on Peach Bottom Unit 2
Dear Mr. Eisenhut:
This letter requests adjustments in the implementation schedules, established by the NRC for several refinements in the design of the Peach Bottom Atomic Power Station, i!. order to minimize the cost of electrical power to area customers.
Specifically, we are requesting an extension in the January, 1982, implementation schedule to permit certain Peach Bottom Unit 2 modifications to be implemented during the refueling outage presently scheduled to commence on February 20, 1982.
One of the schedule adjustments will require a revi sion to an " Order for Modification of Licenses and Crant af Extension of Exceptions for the Peach Bottom Atomic Power Station", issued January 13, 1981.
The request applies to the following requirements and involves Peach Bottom Unit 2 only.
1.
Use ODYN code to recalculate pressurization transients for BWRs operating beyond January, 1982 (letter dated November 4, 1980, D.
G.
Eisenhut, NRC to All Operating Licensees).
2.
NUREG-0737. Post TMI-Requirements, requires implementation by January 1, 1982 of certain changes in the facility design b 4, e 8109110144 e10904 PDR ADOCK 05000277 P
4 Mr.-Darrell G.
Eisenhut Page 2 that would enhance accident response.
The requested schedule revision applies to certain commitments identified in a letter dated ~ December 22, 1980, S.
L. Daltroff, Philadelphia Electric Company, to D. G.
Eisenhut, NRC.
These commitments involve modifications for which a plant outage is required and are discussed in more detail later in this letter.
3.
A letter dated January 13, 1981, Robert W.
Reid, NRC, to E.
G.
Bauer, Jr.,
Philadelphia Electric Company, transmitted an order for modifications of the license.
The order required containment modifications for suppression pool hydrodynamic loading conditions that conform with Appendix A to NUREG-0661 by January 31, 1982.
The requested schedule revision applies to only several of the required modifications and is discussed in more detail later in this letter.
The requested schedule adjustment would delay implementation of the aforementioned design modifications by less than two months and delay implementation of the ODYN code by less than one month.
The schedule adjustment would permit the design modifications to be implemented concurrent with the scheduled refueling outage, thereby eliminating the economic penalty to area customers especially during the winter period when electricity demand and replacement energy costs are expected to be high.
The intent of the modifications are to further enhance the safety margin associated with l'ow probability events.
Given the existing safety margin present in the current design, and since Unit 2 is expected to be in a power coastdown prior to its refueling, sufficient safety margin will exist to justify a short delay in the implementation schedule.
1.
Pressurization Transients - ODYN Code After January, J'92, _11 operating BWRs with General Electric safety analysis are required to'have limiting transients recalculated with the ODYN code.
The Peach Bottom Unit 3 safety analysis utilizes the ODYN code for the fuel cycle that will start in September, 1981.
The requested schedule revision weald delay implementation of thia requirement on Unit 2~by approximately three weeks.
4 Mr. Darrell G.
Eisenhut Page 3
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4 Performing another safety analysis for the last three weeks of operation on the current Unit 2 fuel cycle would not be practical, and would represent an additional strain on Philadelphia Electric's, as well as NRC's limited manpower resources.
The expected power coastdown situation on Unit 2 durir.g this period will further enhance the conservatism in the present safety analysis.
The next Unit 2 fuel cycle will employ the ODYN code as required by the aforementioned November 4, 1980 NRC letter.
2.
NUREG-0737, TMI-Related Requirements The proposed schedule revision would delay implementation of the following modifications beyond the NUREG-0737 implementation schedule of January 1, 1982.
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II.B.3 Post Accident Sampling II.F.1(3) Contaiament High Range Radiation Monitor II.F.1(4)f Containment High Range Pressure II.F.1(5)l Supprest'on Chamber High Water Level II.F.2 i Reactor Level Recorder II.K.3.22 RCIC Suction Transfer II.K.3.28 ADS Accumulator Qualification These modifications are not required to correct identified deficiencies in the current Peach Bottom design.
- Rather, they are intended to either provide additional information that may be helsful in assessing low probability accidents, or provide,surther refinement of the existing conservatism in the pignt emergency response system.
Additionally, manual p(ocedures and techniques are currently in effect for post accident sampling and RCIC suction transfer capabilities.
If an opportunity occurs as a result of a prolonge'd forced outage, we will endeavor to complete these modifications before January 1, 1982.
Otherwise, based on the nature of these improvements, we believe a short delay in their implementation is appropriate.
2 3.
Containment Suppression Chamber Modifications I
The modification work involves bringing the containment i
structurec into compliance with ASME code allowable stresses when reanalysed for newly identified hydrodynamic loads.
The Unit 3 riodifications were completed during the recently concluded refueling outage except for the installation of
a Mr. Darrell G.
EisenPat Page 4 additional supports on torus attached piping systems _which we expect to complete by January 31, 1982.
The majority of the planned improvements on the Unit 2 containment structure were completed during the 198e refueling outage.
The requested schedule revision would delay implementation of the remaining improvements by approximately three weeks i
until February 20, 1982.
The modifications completed to date on Unit 2 are as follows:
1 a.
Quenchers on MSRV discharge lines b.
MSRV discharge line vacuum relief valves c.
Vent header deflectors d.
Downcomer supports 4
Elbows and pipe supports on RHR return lines.
e
_ne remaining modifications for which schedule relief is requested invol're the following tasks:
a.
Install additional snubbers on the MSRV discharge lines in the drywell.
b.
Modify torus internal structures such as the catwalk, monorail, spray header, vacuum breaker penetrations and drain lines, miscellaneous pipe penetrations in the suppression pool, and the stiffening of the vent hes9er-to-downcomer intersection.
c.
Install torus shell stiffeners.
j d.
Install torus tiedown system.
j e.
Stiffen the exterior of torus shell at pipe penetration j
nozzles and install additional supports on external
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attached piping system.
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f.
Torus water temperature monitoring system.
We plan to proceed with any torus modification work, such as item d and part of item e, that can be implemented prior to the start of the outage.
The remaining torus modifications will be completed during the outage.
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Mr. Darrell G.
Eisenhut Page 5 For reasons previously expressed in this letter, we are requesting a revision in the schedule for Unit 2 modifications identified herein to permit their implementation on the upcoming refueling outage scheduled to commence on February 20, 1982.
Should you have any questions regarding this matter, please do not hesitate to contact us.
Very truly yours,
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