ML19256A372
| ML19256A372 | |
| Person / Time | |
|---|---|
| Issue date: | 07/31/1978 |
| From: | Ashar H NRC OFFICE OF STANDARDS DEVELOPMENT |
| To: | Stanford R NRC OFFICE OF STANDARDS DEVELOPMENT |
| References | |
| FRN-43FR46309, RULE-PR-72 NUDOCS 7901050100 | |
| Download: ML19256A372 (2) | |
Text
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MLIC DOCUMEg 999, UNITED STATES NUCLE AR REGULATORY CCT.'T.*.lSs!CT.
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MEMORANDUM FOR:
R. Stanford, FPSSB, SD
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FR0ti:
H. Ashar, SCSB, SD I
SUBJECT:
DISCUSSION AND COMMENTS ON 10 CFR PART 72, " LICENSING REQUIREMENTS FOR THE STORAGE OF SPENT FUEL IN AN INDEPENJENT SPENT FUEL STORAGE INSTALLATION (ISFSI) 72.31(a)(1) The site suitability criteria from Seismic Design point of view are described in 72.66.
It appears that a reference to 72.66 (Subpart 3) will preclude any confusion, and will be consistent with the subsequent [72.31(a)(2), (3), (4) etc.]
conditions of licenses.
72.66 Criteria For Oefining Acceptable Seismic Desicn It should be recognized that the peak acceleration associated with a "horizontial ground notion potential" is not necessarily the same as the maximum design ground acceleration.
Also, the phrase "up to a 500 year reccurrence interval" gives me an impression that we would accept an earthquake having less than 500 year reccurrence interval.
I do not believe this is the intent.
Recognizing the purpose of this section of the Regula-tien, I suggest the following changes.
(a) Design Earthquake (DE) is defined as an earthquake having an reccurrence interval of no less than 500 years.
+(b) Any site, having design maxinum ground acceleration (corresponding to DE) at an IS' 5 foundation level of greater than 0.25, shall be deemed unsuitable for 9
an ISFSI.
(c)
For soil sites, where DE could potentially cause soil failure, it must be shown by a site specific investigation and analysis that soil failure will not occur due to the expected vibratory ground motion at the site.
Sites with potentially unstable soils may be made suitable by remedial action.
'For the pJr;cse of precluding Certein sites from consiceration, the use of r..aos such as those aeveloped by Algernissen and Perkins and further deveic.neo as peak acceleration contours are acceptable.
(See Reference i
7 9 010 5 0/co
R. Stanford 2
(d)
For ISFS1 designs other than the water basin type proposed sites will be evaluated on the basis cf a site specific investigation and analysis.
(e) 51tes which do not meet the suitability requirements of (a) above may be evaluated and accepted in accordance with Section 72.9.
72.71(2)
(ii) It appears that we want applicants to design structures, systems, and components for a horizontal ground motion acceleration >0.25g (sky is the limit).
Philosophically, if we have determined that ISFSI can be designed for an earthquake of 500 year reccurrence interval, it is con-ceivable that we would accept the same recurrence interval for other natural phenomena such as tornadoes, floods and seiches.
In that case it is not understandable why the safety related structures, systems, and components should not be designed for corresponding tornado missiles.
fi/ M H. Ashar Structures and Components Standards Branch Office of Standards Development
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