ML20055E153
| ML20055E153 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 07/05/1990 |
| From: | Haseltine J YANKEE ATOMIC ELECTRIC CO. |
| To: | Wessman R Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20055E154 | List: |
| References | |
| BYR-90-89, NUDOCS 9007110067 | |
| Download: ML20055E153 (4) | |
Text
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i YANKEEATOMICELECTRIC COMPANY "C";,Rs"gVy'*;"l"'
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580 Main Street, Bolton, Massachusetts 01740-1398 v.
1 July 5, 1990 BYR 90-89 l
United States Nuclear P.,6ulatory Commission 3
Document Control Desk' J
Washington, DC '20555 l
Attention:
Mr. Richard H. Wessman, Director Reactor Project Directorate I-3 Office of Nuclear Reactor Regulation Referencess (a) License No. DPR-3 (Docket No. 50-29) l (b) Letter, NRC to Yankee Atomic Electric Company, dated May 1, 1990 (c) Letter, NRC to Yankee Atomic Electric Company, dated May 7, 1990 1
(d) Letter, NRC to Yankee Atomic Electric Company, dated
)
May 15, 1990
Subject:
Reactor Pressure Vessel Evaluation Dear Mr. Wessman Per References (b), (c), and (d), NRC requested additional information regarding the Yankee Nuclear power Station (Yankee) reactor pressure vessel.
Enclosed is our response. Per your instructions we have also transmitted i
twenty (20) copies to your office, five (5) copies to WRC Region I, and one copy to the NRC Document Control Desk.
Our submittal is detailed and extensive. To aid management and staff in i
review of this submittal, we have compiled the requests from the NRC i
correspondence and have indexed each request with the location of the Yankee response in the attached submittal
Response
Reference (b)
Location (1) What is the current Charpy Upper Shelf Chapter 5 Energy in the transverse direction for the Yankee reactor vessel plate?
r (2) Discuss plans for complying with 10CFR, Chapter 3
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Part 50 Appendix G, particularly a means Chapter 7 for reactor vessel inspection.
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United States R*gulatory Commission July 5, 1990 Attention:
Mr. Richard H. Wessman Page 2 (3) Discuss plans for accurately determining Chapter 5 the reference temperatures for the beltline lower plate and circumferential weld.
Reference (c)
(1) Discuss installation of surveillance Chapter 4 capsules in the reactor at accelerated (high flux) positions and at low flux positions.
(2) Discuss removal of the shield tank Chapter 7 or other plant structural changes L
necessary for UT inspection of the beltline.
(3) provide fabrication history (welding Chapter 1 l
and heat. treatment) and inspection (both Chapter 7 l
preservice and in-service) results for beltline materials and for other vessel materials that were fabricated in the l
same manner as the beltline materials.
(4) ' Discuss fabrication history (cross-rolling Chapter 1 l
and heat treatment) of beltline plates.
Chapter 5 Based on the fabrication history, what is the Charpy Upper Shelf Energy (USE) in the transverse direction for the beltline phases -- unirradiated and in 1990 and in l,
2000?
h (5) Identify the heat numbers for the weld Chapter 5 wire used to fabricate each beltline weld.
Are the heats of wire used to fabricate the Yankee Rowe reactor vessel beltline welds the same as the Belgium Reactor Unit 3 (BR-3) welds? Based on the heats of wire used, what are the amounts of copper, nickel and l
phosphorous in each beltline weld? What is L
the Charpy USE for each beltline weld
-- unirradiated and in 1990 and Jn 2000?
(6) In NRL Report 6616, it is reported that the Chapter 2 Yankee Rowe cold les temperature was 495'F during Cycle II, 500'F during Cycle III, and 505'F during Cycle IV.
In addition, Yankee Rowe produced power during coastdown. At these reactor operating temperatures, the amount of neutron irradiation embrittlement i
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,s
United States Regulatory Comission July 5, 1990 L
Attention Mr. Richard H. Wessman page 3 could be greater than predicted by Regulatory Guide 1.99, Revision 2 and the PTS Rule 50.61.
What is the average cold les temperature (excluding coastdown) during each core cycle? Does Yankee Rowe still operate with coastdown periods where the cold les temperature is less than 500'Ff When did constdown operation stopf What is the accumulated neutron fluence during these coastdown periods?
(7) Based on BR-3 data in a report by A. Fabry, Chapter 5 dated October 22, 1983, the increase in reference temperature and decrease in Charpy USE is greater at 500'F operating temperatures.
Since Regulatory Guide 1.99, Revision 2 is applicable _to plants with nominal irradiation temperatures of 550'r and Yankee Rowe operates below 525*, what is the predicted reference temperature and the Charpy USE for the circumferential beltline weld in lo' 0 and 20007 Provide all data that supports these values.
l-(8) Based on the Yankee Rowe surveillance data, Chapter 5 l
the increase in reference temperature for the beltline plates could be greater than o
the values predicted following the tables in Regulatory Guide 1.99 Revision 2.
Based on its surveillance data, what is the predicted reference temperature of each plate in 1990 and 2000f If there is-other lI data available that Yankee Rowe is relying upon to predict the reference temperature of each plate in the beltline, provido it.
Based on this data, what is the reference temperature l
for each beltline plate in 1990 and 2000f (9)Section V.C in 10CFR50, Appendix G Chapter 3 identifies three requirements which must be satisfied to continue operation of a reactor vessel when its Charpy USE falls below 50 ft-lb.
Discuss how Yankee Rowe plans to satisfy each of these requirements for the l
weld metal and plates that are predicted to l
have Charpy USE less than 50 ft-lb.
(10) Discuss the need for, benefit and feasibility Chapter 8 of performing an anneal at 650*F or 850'F.
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United States Regulatory Commission Jul/ 5, 1990 t
Attentiont Mr. Richard H. Wessman Page 4 l'
EtitttD9.e (d) e (1) Provide a PTS analysis including operational Chapter 6 methods for reducing the frequency and severity of a PTS event. Provide a sensitivity study of the effect of nil ductility transition reference temperature on the failure probability of the reactor vessel resulting from PTS events.
(Use values as high as 400*F.)
(2) Provide plans and programs for UT inspection Chapter 7 of the Reactor Pressure Vessel (RPV) beltline area.
(3) Provide plans and programs for annealing Chapter 8 the Reactor Pressure Vessel.
(4) Provide plans for 1993 in-service Chapter 7 inspection (ISI) including any expected relief requests.
We are currently planning to meet with the NRC on July 17, 1990 in Rockville to discuss the attached evaluation report.
If there are any questions regarding this submittal that can be easily addressed prior to the meeting, please let me know.
Sincerely, Goa John D. Haseltine Project Director - Yankee -
JDH/dhm/WPP77/104 Attachments I
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