ML19289A055
| ML19289A055 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 12/20/1978 |
| From: | Stello V Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19289A054 | List: |
| References | |
| NUDOCS 7901040193 | |
| Download: ML19289A055 (5) | |
Text
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of
)
)
PORTLAND GENERAL ELECTRIC COMPANY
)
Oceket No. 50-344 THE CITY OF EUGENE, OREGON
)
PACIFIC POWER & LIGHT COMPANY
)
)
(Trojan Nuclear Plant
)
EXEMPTION 1.
Portlan:1 General Electric Cor.cany, The City of Eugene, Oregon and Pacific Power & Light Cocpany (the licensees) are the holders of Facility Operating License No. NPF-1 which authorizes the operation of the nuclear power reactor known as Trojan Nuclear Plant ( the f acility) at steady reactor power levels not in excess of 3411 megawatts thermal (rated power). The f acility consists of a Westing-house Electric Corporation designed pressuri:ed water reactor (PWR) located at the licensees' site in Colurbia County, Oregon.
II.
In accordance with the requirements of the Commissich's ECCS Acceptance Criteria 10 CFR 50.46, the licensees submitted on March 31, 1977 an ECCS evaluation for proposed operation usino 17 X 17 fuel manufactured by the Westinghouse Electric Corporation. Tnis evaluation included limits on the peaking factor. The ECCS performance evaluaticin submitted by the licensees was based upon an ECCS evaluation developed by the Westinghouse Electric Corporation (Westinghouse), the designer of the Nuclear Steam Supply System 790104 o M 3
2 for this f acility. The Westinghouse ECCS Evaluation Mocel had been previously found to confom to the requirements of the Commission's ECCS Acceptance Criteria,10 CFR Part 50.46 and Appendix K.
The evaluation indicated that with the peaking factor limited as set forth in the evaluation, and with other limits set forth in the facility's Technical Specifications, the ECCS cooling perfomance for the facility would confom with the criteria contained in 10 CFR 50.46(b) which govern calculated peak clad temperature, maximum cladding oxidation, maximum hydrogen generation, coolable geometry and long-term cooling.
On March 23, 1978 Westinghouse infomed the Nuclear Regulatory Commission (NRC) that an error had been discovered in the fuel rod heat balance equation involving the incorrect use of only half of the volumetric heat generation due to metal-water reaction in calculating the cladding temperature. Thus, the LOCA analyses previously submitted to the Commission by licensees of Westinghouse reactors were in error. The staff promptly detemined that no immediate action was required to assure safe operation of these plants. Moreover, the Trojan facility has not operated since March 17, 1978.
The error identified would result in an increase in calculated peak clad temperature, which, for some plants, could result in calculated tempera-tures in excess of 2200'F unless the allowable peaking factor was reduced i
somewhat. Westinghouse identified a number of other areas in the approved model which Westinghouse indicated contained sufficient conservatism to offset the calculated increase in peak clad temperature resulting from the
. Four of these areas were generic, correction of the error noted above.
applicable to all plants, and a number of others were plant specific.
As outlined in the attached Safety Evaluation Report (SER), the staff deter-mined that some of these modifications would be appreoriate to offset to some The attached SER extent the penaity resulting f rom correction of the error.
sets forth the value for each modification applicable to each facility.
Revised computer calculations correcting the error, noted above, and incorporating the modifications described in the SER have not been run However, the various parametric studies that have been for each plant.
made for various aspects of the approved Westinghouse model over the course of time provide a reasonable basis for concluding that when final revised cal-culations for the facility are submitted using the revised and corrected model, they will demonstrate that when operated at the peaking factors set fortt, in the SER operation will confom to the criteria of Such revised calculations fully conforming to 10 CFR 50.46(b).
have not yet been completed by Westingneuse for the Trojan 10 CFR 50.46 They are expected to be completed and submitted before April,1979 facility.
Operation of the facility would nevertheless be technically in non-confomance with the requirements of 150.46, in that specific computer runs for the particular f acility employing revised models with the Westinghouse metal-water error corrected and with the proposed model changes considered as a complete entity will not, be complete for some
4 ti re.
However, operation as $;ecified in this Extretion will assure that the ECCS system will conform to the performarce criteria of $50.46.
Accordingly, while the actual computer runs for the specific facility are carried out to achieve full comoliance with 10 CFR !!0.45, operation of the facility will not endanger life or property or the cormon defense and security.
In the absence of any safety problem related to this ECCS matter associated with operation of the facility during the period until the computer com-putations are completed, there appears to be no public interest considerttien favoring restriction of the operation of the captioned facility. Accordingly, the Connission has determined that an exemption in accordance with 10 CFR 550.12 is appropriates The specific exemption is limited to the period of time necessary to complete computer calculations.
IV.
Copies of the Safety Evaluation and the following documenti are available for inspection at the Commission's Public Document Room it 1717 H Street, Washington, D. C.
20555, and are being placed in the Commission's local public document room at the Columbia County Courthouse Law Library, Circuit Court Room St. Helens, Oregon 97501.
(1) Letter from Westinghouse to NRC dated April 7,1978.
(2) Letter from Portland General Electric Company, to Mr. A. Schwencer, Operating Reactors Branch #1, dated April 12, 1978.
. (3) This Exemetion in the matter of Trojan Nuclear Plant.
Wherefore, in accordance with the Commission's regulations as set forth in 10 CFR Part 50, the licensees are hereby granted an exenotion from the re-cuirements of 10 CFR 650.46(a)(1) that ECCS performance be calculated in accordtnce with an acceotable calculational model which conforms to the provisions in Accendix K, without errors discussed herein. This exenotion is conditioned as follows:
As soon as possible, but not later than April 1,1979, the licensees shall submit a reevaluation of ECCS cooling per-formance calculated in accordance with the Westinghouse Evaluation Model, approved by the '<RC staff and corrected for the errors described herein.
FOR THE NUCt. EAR REGULATORY COMMISSION Victor Stello, J.. Director Division of Operating Reactors Office of Nuclear Reactor Regulation Dated at Bethesda, Macland this 20th day of December,1978