ML20044C592
| ML20044C592 | |
| Person / Time | |
|---|---|
| Issue date: | 03/24/1993 |
| From: | Wichman K Office of Nuclear Reactor Regulation |
| To: | Choi Y KOREA, REPUBLIC OF (SOUTH KOREA) |
| Shared Package | |
| ML19342A692 | List: |
| References | |
| NUDOCS 9304080203 | |
| Download: ML20044C592 (2) | |
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WASHINGTON, D.C. 20555 '
- 0f.** Young Hwan Choi MAR h. %
Reactor Systems Department Korea Institute of Nuclear Safety l
P.O. Box 16, Daeduk-danji, Taejon Republic of Korea
Dear Dr. Choi:
l Your letter dated March 2,1993 contained certain questions which required i
some investigation on my part in order to answer.
Therefore, excuse my delay in replying.
In response to your first question, the original meaning of "least favorable combination" was to specify the limiting location in the piainh ru'n in terms -
of stress (load) and material toughness.
In practice this ias meant what you identified in your letter as item (1), i.e., the combination ~of the highest load in the system under'LBB evaluation and the worst material properties among the base metal, the weldments and the 's'afe ends. " '
Secondly, you inquired as to whether there are any.PWR plants in which the limit of the leak detection system was extended!to"0'.'5 gpa for'the purpose of d
leak-before-break application. The answer is yes - the PWR is Beaver Valley.
The application for LBB for this plant was made ind approved'in the'19861 timeframe under.a previous NRR organization.
I played'no role in-the review t
of LBB for Beaver Valley.
I would not, for 'a number ~of reasorls; approve an application for LBB based on a 0.5 gpm leakage detectability limit using systems specified by Regulatory Guide 1.45.. I am prepared to elaborate on this issue.if you wish.
g Regarding your questions about"the background asktoyhyTg'('l2) ~oFEq(13) j originally in S.R.P. 3.6.'2F5TP MEB hpet!CIMs3M198& was. excluded in '
BTP MEB-3-1 (Rev. 2 July 1987) for the: purposes of postulating ~ breaks at -
' intermediate locations, I refer *you to-
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Mr. David Terao Division of Engineering
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U.S. Nuclear Regulatory Commission
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Mail Stop 7H15 Washington, D.C. 20555 i
Telephone: 301-504-3317 I have relayed your question to Mr. Terao. However, I.have attahhed for your information an internal memorandum which discusses this issue, its impact and i
proposed resolution.- I have received permission to send.you this memorandum on condition that it not be released outside of your o,rganization for the time being.
Finally, perhaps }ou can put me in contact with the appropriate organizations l
(and individuals therein) who have access to and can~ authorize:the release of.
the following types of reactor vessel material information to the U.S. Nuclear Regulatory Commission:
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1 Dr. Choi -
Power reactor surveillance data Test reactor data.
Annealing recovery data Specific data requested involves material property data, chemistry, irradiation information (fluence, flux, temperature) and raw Charpy test data (energy and % shear vs. temperature).
I should note that confidentially of the data source can be assured if required and that data will be supplied to IAEA international surveillance data base activity, if the donor wishes.
As I indicated in my letter to you of November 10, 1992, I plan ~on visiting Korea in May.
I would like to have a day or two of discussion with you and your colleagues.
I would appreciate any suggestions from you on areas you_may wish to discuss.
I will communicate with you again soon about my projected-visit.
Best regards,
/b6I!
Keith R. Wichman, Chief Materials Integrity Section, EMCB Division of Engineering
Enclosure:
As stated DISTRIBUTION:
cc:
R. Hauber, IP Central Files
'EMCB RF DE EM KW1 3/;L 93 0FFICIAL RECORD COPY WP FILENAME: G:\\WICHHAN\\LTRCH01.KRW 1
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