ML20045G694
| ML20045G694 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 07/09/1993 |
| From: | Opeka J CONNECTICUT YANKEE ATOMIC POWER CO., NORTHEAST UTILITIES |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20045G695 | List: |
| References | |
| REF-GTECI-A-46, REF-GTECI-SC, TASK-03-06, TASK-3-6, TASK-A-46, TASK-OR, TASK-RR B14504, GL-87-02, GL-87-2, NUDOCS 9307150059 | |
| Download: ML20045G694 (3) | |
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y NORTHEAST UTILITIES cenerai Offices. seiden street. Beriin. Connecticut 1
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P.O. BOX 270 '
HARTFORD, CONNECTICUT 06141-0270 J ((CC,C, (203) 665-5000 k
L July 9, 1993 Docket No. 50-213 B14504 Re: USI-A46 ISAP Topic 1.04 SEP Topic III-6 U.S. Nuclear Regr'atory Commission Attention: Docur int Control Desk Washington, DC 20555 Gentlemen:
Haddam Neck Plant Verification of Seismic Adeauacy of Pipina The purpose of this letter is for Connecticut Yankee Atomic Power Company
-(CYAPCO) to propose final closure of the remaining open seismic piping issues for the Haddam Neck Plant, in particular Systematic Evaluation Pogrom (SEP)-
Topic III-6.
Unresolved Safety Issue A-46,
" Seismic Qualification of Equipment in Operating Plants" was established because.the NRC Staff concluded that the seismic adequacy of certain equipment in operating nuclear -power plants must be reviewed against the criteria not in use when these plants were licensed.
CYAPC0 has been participating in the. Seismic Qualification Utility Group effort to use actual earthquake experience to demonstrate seismic adequacy of equipment (i.e., seismic margins) in older nuclear units.
CYAPC0 now wishes to explore using a seismic margins approach as an alternate method for completing the topic of seismic verification of piping systems.
Specifically, CYAPC0 plans to confirm the seismic adequacy of the Haddam Neck Plant's main steam, feedwater, and service water systems' piping by using the seismic margins methodology described in the attached procedures.
As the NRC Staff stated in Generic Letter 87-02,"'
" direct application of current seismic criteria...to older plants could require extensive, and probably impracticable, modification of these facilities.
An alternative resolution of this problem is set out in the enclosure to this letter (Generic Letter 87-02).
This approach makes use of earthquake experience data supplemented by test results to verify the seismic capability of equipment below specified earthquake motion bounds."
The NRC Staff and industry, (1)
H. R. Denton letter to All Holders of Operating Licenses Not Reviewed to Current Licensing Criteria on Seismic Qualification of Equipment,
" Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating Reactors, Unresolved Safety Issue (USI) A-46 (Generic Letter 87-02)," dated February 19, 1987.
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j U.S. Nuclear Regulatory Commission 1
-814504/Page 2 July 9, 1993 including CYAPC0, believe this to be the most reasonable and cost-effective means to ensure that the intent of General Design Criterion 2 is met at older nuclear plants.
Very few components of nuclear power plants' systems are unique to nuclear r
facilities.
Nuclear plant systems include electrical panels and switchgear, i
air compressors, tanks, piping, conduit, and many other items that are common components of conventional power plants and industrial facilities.
-The seismic experience data base was developed to verify seismic adequacy for equipment which was purchased "off-the-shelf" or for existing equipment which requires an upgrade in seismic classification.
By reviewing the results of strong ground motion earthquakes at facilities that contain equipment similar to that found in nuclear plants, conclusions can be drawn about the probable performance of nuclear plant equipment during and after a design-basis earthquake.
CYAPC0 is proposing to use a seismic margins-type review-to address the issue of seismic adequacy of piping at the Haddam Neck Plant. CYAPCO's verification program will consist of design document examinations and visual inspections /
walkdowns of piping systems at Haddam Neck to assess the ruggedness of the piping. This assessment would then be verified by a bounding sample computer analysis.
The proposed program that would be used is described in the attachment to this letter.
The existing seismic upgrade program has been derived from the SEP and is evaluated for implementation in our Integrated Safety Assessment Program.
CYAPC0 believes that the use of the SEP criteria on those selected portions of piping - will result in the expenditure of significant resources and will result in, at best, a. marginal increase in -
safety.
CYAPC0 believes that approximately equivalent technical results can be achieved by the application of the seismic margin methodology to-piping as described in the attachment, and that the use of this seismic margins program may avert unnecessary costs that would otherwise be incurred by what we believe to be a requirement with a minimal safety benefit.
CYAPC0 proposes that a meeting be held between CYAPC0 and the NRC Staff whereby CYAPC0 can present to the Staff our proposed plan.
During this informational meeting, CYAPC0 will be prepared to discuss technical issues, as well as schedular considerations. We suggest a meeting in mid-August.
If you have any questions, please contact my staff.
Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY d bd, J. F. Opeka/
U Executive Vice President cc: See page 3
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U.S. Nuclear Regulatory Commission B14504/Page 3 July 9,1993 cc:
T._T. Martin, Region I Administrator L. B. Marsh, Project Directorate III-1 A. B. Wang, NRC Project Manager, Haddam Neck Plant W. J. Raymond, Senior Resident Inspector, Haddam Neck Plant I
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