ML20076J665
| ML20076J665 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/30/1983 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0619, RTR-NUREG-619 GL-81-11, NUDOCS 8307060081 | |
| Download: ML20076J665 (2) | |
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PHILADELPHIA ELECTRIC COMPANY 23O1 MARKET STREET F'.O. BOX 8699 PHILADELPHI A. PA.19101 5HIELOS L DALTROFF n.E*lic"EUEo=
June 30, 1993 Docket Mos. 50-277 50-279 Mr. Darrell G.
Ei s erlau t, Director Division of Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Requlatory Conmission Washington, D.C.
20555
Dear Mr. Eisenhut:
This is a follow-up to our letter sent to you on January 21, 1081, and concerns implementation of NUREG-0619, "BWR Feedwater Nozzle and Control Rod Drive Return Line (CRDPL) Nozzle Cracking."
In the January 21, 1991, letter, Philadelphia El ectric Company committed to innta11, by June 30, 1983, a feedwater nystem low flow controller and reroute the Reactor Water Cleanup (RWCU) return line to both feedwater lines on Peach Rottom Units 2 and 3.
Subsequent to this commitment, the NRC issued Generic Letter 91-11 Indicating that variations in the low flow controller design would be accentable provided that, by analysis, the design meets the feedwater nozzle crack initiation and growth limits accepted by the NRC.
Generic Letter Al-11 also states that the benefit from rerouting the RWCU return line may not be an great as originally anticipated.
- he feedwater low flow controll er (startup val.ve) has been installed on both units at Peach Bottom.
The Unit 2 valve went i nto service in June, 19A2, and the Uni t 3 valve will be ready for service for use in returning the Unit to service following completion of the present ref ueling outage.
Engineering data and a fatigue analysis has indicated that it is not necessary to reroute the RWCU return line.
According to NEDE-21821, the primary benefit from the reroute is a significant reduction in crack initiation corresponding to a reduction.in the fatigue usage factor on the order of 0.24.
The
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8307060081 830630 PDR ADOCK 05000277 g0 P
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Mr. Darrell G. Eisenhut Page 2 f atique analysis indicates that the maximum reduction in feedwater nozzle fatique usaqe factor associated with the PWCU return line reroute is approximately 0.06 over a forty-vear life.
Most of the fatique usace is accumulated at hiqh feedwater flowraten when the feedwater temperature is hardiv chanced by the rel ativel y low QWCU fl owra te.
Tharefore, the net reduction in usage factor in minimal and does not justify the reroute.
NURPG-061n calls for a pl ant speci fi c fracture nechanics analysis for the low flow controller which recuires use of sneci fi c controller characteristics and feedwater flow and temperature data with the low flow controller in service.
The fracture mechanics analyses to justify the design of tha low flow controller is nearly compl ete.
Annrontiate data for the analysis could not be obtained until initial operation on Unit 2 of the low flow controller, with control elenents properly tuned.
The low flow controller has performed satisfactorily and we anticipate that the final analysis will fully justify not rerouting the RWCU return line.
NUREG-0619, paragraph 4.4. 3, requires a detailed re port describing theme modi fi cations, includinq justification for our design.
In reviewing NUREG-0610, we were unable to identify a submittal date for the report and propose a date of September 30, 1943, to allow sufficient time for the NSS9 supolier to comniete the fracture machanics studies.
At that tine, we will provide a detailed descrintion of the modi fications along with analysem to show comnliance with the intent of NUPEG-0614 If you have any questions or recuire additional i n f orma ti on, do not hesitate to contact us.
Very truly yours, l
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