ML19274E716
| ML19274E716 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 04/12/1979 |
| From: | Utley E CAROLINA POWER & LIGHT CO. |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| GD-79-1005, NUDOCS 7904170213 | |
| Download: ML19274E716 (2) | |
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Carolina Power & Light Company April 12, 1979 FILE: NG-3514(B)
SERIAL: GD-79-1005 Office of Nuclear Reactor Regulation ATTENTION:
Mr. T. A. Ippolito, Chief Operating Reactors Branch No. 3 United States Nuclear Regulatory Commission Washington, D. C.
20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NO. 1 DOCKET No. 50-325 LICENSE NO. DPR-71 AD%TIONAL INFORMATION - REACTOR COOLANT PRESSURE BOUNDARY
Dear Mr. Ippolito:
In accordance with the NRC staff request of August 10, 1976, Carolina Power & Light Company (CP&L) has been proceeding with an analytical program for Brunswick neeam Electric Plant, Unit No. 1, to determine the effecta of reactor vessel annulus pressurization and asymmetric loads created by a postulated loss of coolant accident (LOCA). This le_tter is to supplement our initial response dated September 22, 1976. To date, pressure loading calculations within the annulus haVe be-in developed by the plant Architect-Engineer, United Engineers and Constructors, Inc., so that they may be used by the reactor vendor, General Electric, to compute total loading forces on the reactor vessel supports and sup-port pedestal, as well as the reactor vessel internals. The analytical program is in a preliminary stage, with detailed modeling of the Brunswick Unit I annulus region and drywell remaining to be completed before detailed annlyses can be per-formed.
The analyses will be performed for an assumed break at the feedwater nozzle and the recirculation loop outlet nozzle. To date, the pressure loading calculationo ptovided by United Engineers and Constructors for the two break locations have been assessed in a preliminary review by General Electric. This preliminary review has indicated that the later, detailed analyses should result in acceptable support and internals loadings for the feedwater nozzle break with the present configuration of the feedwater piping and shield wall penetration, but that some modification would be required to limit annulus pressurization loads for the recirculation outlet nozzle break. This modification could take the form of a guard pipe, or deflector, to direct the bulk of the blowdown flow outside the annulus region.
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A r. T. A. Ippolito April 12, 1979 M
As a result of these preliminary scoping analyses, CP&L is proceeding with development of the detailed analytical models required to properly assess the support and internals loadings, and with definition of the type of modifica-tion required to assure acceptable loadings for the postulated recirculation out-let nozzle break. Completion of the above analyses is scheduled for December, 1979. We anticipate that any modifications that would result from this analytical program could be installed during the 1980 refueling outage on Brunswick Unit 1.
If you desire additional information on the Brunswick Unit 1 annulus pressuriza-tion program or desire to meet with us to discuss our program, please inform us.
Yours very truly,
[g E. E. Utley Senior Vice President Power Supply MLB/DBW/mf