ML17256A880
| ML17256A880 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 04/29/1982 |
| From: | Maier J ROCHESTER GAS & ELECTRIC CORP. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-02-02.A, TASK-03-02, TASK-03-04.A, TASK-03-07.B, TASK-2-2.A, TASK-3-2, TASK-3-4.A, TASK-3-7.B, TASK-RR NUDOCS 8205040592 | |
| Download: ML17256A880 (8) | |
Text
REGUL RY INFORMATION DISTRIBUTI
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"ACCESSION NBR:8205040592 DOC ~ DATE: 82/04/29 NOTARIZED:
NO FACIL:50-204 Robert Emmet Ginna Nuclear Pl anti Uni't li Rochester G
AUTH'AME AUTHOR AFFILIATION MAIEREJ ~ E, Rochester Gas 8 Electric Corp'ECIP
~ NAME RECIPIENT AFFILIATION CRUTCHFIELDED ~
Operating Reactors Branch 5
DISTRIBUTION CODE $
A035S TITLE: SEP Topics NOTES:NRR/DL/SEP icy ~
SUBJECT; Proposes that SEP ToPics II "2 ~ Az III 2t III' A KIII 7 p
consol idated in one overal,l;structur al r eview of plant. Also proposesiwhere review of topics affects J esolution of related;toPicsicvaluation be coordinated.
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~ 89 EAST AVENUE, ROCHESTER, N.Y. 14649 JOHN E. MAIER Vice Preekient ICLCPHONC ARc*cooc vie 546.2700 April 29, 1982 Director of Nuclear Reactor Regulation Attention:
Mr. Dennis M. Crutchfield, Chief Operating Reactors Branch No.
5 U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Subject:
SEP Structural Re-evaluation R.
E. Ginna Nuclear Power Plant Docket No. 50-244
Dear Mr. Crutchfield:
During the review of SEP topics related to the structural design of the Ginna facility, a number of issues= requiring further analysis have been defined.
These include topics II-2.A, III-2, III-4.A, and III-7.B.
Rochester Gas and Electric proposes that all of these topic reviews be consolidated into one overall structural review of Ginna.
RGRE also proposes
- that, where the review ofthese "structural SEP topics directly, affects the resolution of'elated topics such as seismic, fire.,protection, and pipe breaks, the evaluation of all top'ics be coordinated.
It is considered that such an overall review would provide the best, use of the Systematic Evaluation Program concept of integrating modifications.'GRE considers that the following fourfold program plan should be developed in order to define the parameters to be used as the structural basis for the Ginna plant.,
as related to the above-stated SEP topics-.
1) 2)
3) 4)
development of a suitable range of input parameters development of reasonable acceptance criteria definition of structures and systems requiring protection value-impact assessment In ut arameters The present regulatory guidance would impose a "design basis tornado" with a probability of occurrence of about 10 per year.
This results in a 250 mph tornado.
- However, RGEE does not consider that an upgrade to such a low probability event would provide substantial additional rotection (from 50.109).
Protection from tornadoes should be comparable to other plant risks.
A proper level of risk for a tornado event at
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ROCHESTER GAS AND ELECTRIC CORP.
April 29, 1982 Mr. Dennis M. Crutchfield SHEET NO.
the Ginna site will be tied to issues such as the proposed Commission safety goal. It is expected that the range of interest for tornado occurrence will be )hose wigh an intensity whose probability is on the order of 10 to 10 per year.
RGEE is also evaluating the threshold tornado velocities which could produce tornado-generated missiles.
If missiles would not be expected to become airborne due to the postulated tornado
- speeds, the effects of tornado-generated missiles will not be considered.
The other natural phenomena under review as part of this structural analysis (wind,
- snow, and combinations) will be evaluated using a comparable risk basis.
Acce tance Criteria The suitable stress limits and suitable code applications for structural components will be developed, as applicable to the particular level of natural phenomena involved (extreme
- loads, upset loads, etc.).
These stress limits ensure safety margins are maintained under all postulated loading conditions.
Definition of Structures and S stems Re uirin Protection It is not postulated that an accident would occur concurrent with a
- tornado, unless tornado effects could cause an accident.
RGGE thus proposes that those structures,
- systems, and components required to attain and maintain safe hot shutdown should be protected, as well as those systems whose failure could result in releases whose consequences are comparable to the guideline limits of 10 CFR Part 100.
Additionally, RGGE proposes that the plant be able to achieve a safe cold shutdown condition, using any suitable means available.
This could include using uncon-ventional
- means, such as portable or non-safety related
- systems, as long as they would not. be affected by a tornado.
No particular time limit would be imposed, as long as the plant could be main-tained in a safe shutdown condition at all times.
Value-Im act Assessment Once a structural analysis format for the Ginna structures is developed, a range of input parameters is determined, and the acceptance
- criteria, and structures to be protected, are established, RGGE will evaluate the effects of various levels of loadings on the Ginna structures.
An estimate of the impact can then be made.
A decision as to the proper level of tornado, wind, and snow load protection to be used as the design basis for Ginna can then be made by RGSE, and proposed to the NRC.
RGRE believes that, without going through a detailed, com-prehensive analysis such as this, no legitimate estimate of the impact and cost of proposed modifications associated with various natural phenomena intensities, can be made.
This proposed program plan is a major undertaking for RGGE, and will require significant
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ROCHESTER GAS AND ELECTRIC CORP.
April 29, l982 Mr. Dennis M. Crutchfield SHEET NO.
inhouse and contractor effort.
No vendor has as yet been selected for the structural model development and analysis tasks, although RGSE is now in the process of soliciting bids.
- Thus, RGGE does not expect to identify the design basis for the structural up-grading of Ginna for at least eight to ten months after contractor selection.
RGSE would, however, plan to provide the NRC with periodic updates relative to the progress of this program.
We trust that this program and schedule provides the NRC with the assurance that RGSE is engaging in a dedicated effort to most efficiently resolve the structural issues now under review in the Systematic Evaluation Program.
Very truly yours, Jo E. Maier