ML19318A802
| ML19318A802 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 06/06/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19318A797 | List: |
| References | |
| NUDOCS 8006240177 | |
| Download: ML19318A802 (3) | |
Text
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,k UNITED STATES 9
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NUCLEAR REGULATORY COMMISSION a
WASHINGTON, D. C. 20555 s,y+.
,f SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 44 TO FACILITY OPERATING LICENSE NO. NPF-1 PORTLAND GENERAL ELECTRIC COMoANY THE CITY OF EUGENE, OREGON PACIFIC POWER AND LIGHT C0f9ANY TROJAN NUCLEAR PLANT DOCKET NO. 50-344 Introduction By letter dated December 24, 1979, supplemented by letters dated March 4 and 17, 1980, Portland General Electric Company, Tan Iiuclear Plant in Columbia County, et al. requested changes to the Technical Specifications (TSs) for operation of Tro Oregon. The licensee proposes changes to certain power distr.ibution limits (radial peaking factor, FrodinsertionlimNs,andnuclearenthalpyrisehotchannelfactor,FaH) and control for the reactor core. The acceptability of each of these changes is addressed below.
Discussion and Evaluation 1.
Fxy The present TSs require F not to exceed 1.55 for all unrodded core planer above 8 ft and 1.65 for uhodded core planes below 8 ft.
The licensee proposed to change this requirement to permit an Fxy of 1.65 along
' the total active fuel length.
To support this proposal the licensee has shown that for Cycles 2 and 3 the existing FQ limit of 2.32 is still satisfied with this new requirement for Fxy (Reference 4). We, therefore, find this change acceptable.
2.
The licensee has proposed eliminating a reduction in F g due to fuel rod bowing 3
effects on DNBR.
The proposal is based on the completion of tests run by Westinghouse (Reference 3) and. the approval by the staff of a Westinghouse calcu-lational nodel based on these tests (Reference 1). The Westinghouse model is generic and applicable lo the 17 x 17 fuel used by Trojan.
The NRC approval of the generic model is also applicable to the Trojan fuel.
Even with application of the new model, a reduction in DNBR is still required.
However, there are several factors which are included in the thermal hydraulic design of the Trojan core which are used by the licensee to offset this reduction.
These factors are listed in Table 1 below.
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e-r Trojan Nuclear' Plant TABLE-1.
1.28 DNBR vs.1.30 ONBR
-1.6%
DNB correlation multiplier
.865 vs. 88 1.7%
TDC.038 vs. 051 in F's only
-1.2%
Pitch reduction 1.7%
Extra grid 2.9%
9.1%
The increase in flow over that of the value used in the safety analysis is 2%.
Therefore, the - total ma.rgin.available to offset the reduction in DNBR due to fuel rod bowing is 11.1%.
For cases. of reduced flow (such as during the Loss of Flow transient), the reduction in DNBR cha to fuel rod bowing is 14%. The licensee will maintain at least 3% additional margin for the Loss of Flow transient.
This additional margin will be in the form of the difference ~in DNBR between the 1.3 DNBR safety limit and the calculated minimum DNBR.
If this 3% margin car.not be maintained, a reduction in FaH will be required or an equivalent change to the thermal hydrau-lic conditions-of the Trojan ' reactor, as discussed in the revised basis state-ment for this-TS.
Since the removal of the reduction in FtH is based on approved models, and sufficient. design margin is used to offset the reduction in DNBR, we find this change acceptable. However, any change such as using calculational methods other than those of References 2 and 3 or a change to the Limiting Conditions of Operation of Table 3.2-1 of'the Trojan TSs would require a reevaluation of the TS value of FaH-3.
The licensee proposed a change to the Rod Insertion Limits (Figure 3.1-1 of the TS). The proposed insertion limits are shallower than the existing limits and
. shallower than tk ' the licensee stated were used in the Safety Analyses for Cycles 2 and 3.
Since. shallower rod insertion is less limiting and the safety analyses were done i
assuming deeper. insertion, we find this change acceptable.
Environmental Consideration We have determined that' the amendment does not authorize a change.in
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- effluent types or total amounts nor an increase in power level and will-not result in-any significant envircamental impact. Having made this determination, we have further concluded that the amendment involves antaction which is insignificant from the standpoint of
- environmental impact 'and, pursuant to 10 CFR 51.5(d)(4), that an
- environmental ; impact. statement or negative ' declaration and environ-
. mental; impact appraisal? need:not be' prepared in connection with the issuance of this amendment.
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Trojan Nuclear Plant Conclusion We have concluded, based on the consideration; discussed above, that:
(1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operatien in the proposed manner, and (3) such activities will be conducted in canpliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date:
June 6, 1980 References 1.
Letter from C. Goodwin, Jr., PGE to A. Schwencer, USNRC, December 24, 1979.
2.
Letter from J. Stolz, USNRC to Thomas Anderson, Westinghouse Electric Corporation April 5,1979.
3.
Letter from Robert A. Wiesemann, Westinghouse Electric Corporation to Denwood F. Ross, USNRC, October 24, 1977.
4.
Letter from C. Goodwin, Jr., Portland General Electric to A. Schwencer, USNRC, March 4,1980.
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