ML19350B314
| ML19350B314 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 03/16/1981 |
| From: | Withers B PORTLAND GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19350B311 | List: |
| References | |
| NUDOCS 8103200254 | |
| Download: ML19350B314 (4) | |
Text
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O PORTLAND GENERAL ELECTRIC COMPAhT EUGENE WA~ER & ZLECTRIC BOARD AND
-PACIFIC POWER & LIGHT COMPAhT TROJAN NUCLEAR PLANT Operating License NPF-1 Docket 50-344 License Change Application 71 Licensee hereby requests an amendment to License NPF-1 to incorporate a change in the MODE 5 shutdown margin requirement.
PORTLAND GENERAL ELECTRIC COMPANY a
By
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Bart D. Withers Vice President Nuclear.
' Subscribed and sworn to before me this 16th day of March 1981.
//d nb ku Notary Public oF0regon My Commission Expires:
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.BDW/GMY/41m4A16-8103200$$q
LCA 71 Page 1 of 3 LICENSE CHANGE APPLICATION Technical Specification 3/4.1.1.1, reauiring a minimum shutdown margin of 1.6 percent ak/k, applies to Plant operational MODES 1 through 4.
Techni-cal Specification 3/4.1.1.2 requires a shutdown margin of 1.0 percent ak/k and applies to MODE 5.
This proposed Technical Specification revision con-solidates these two Technical Specifications, eliminating Technical Specification and Technical Specification Bases 3/4.1.1.2 and increasing the MODE 5 minimum shutdown requirement to 1.6 percent ak/k. Shutdown requirements for MODES 1 through 4 remain unchanged. Proposed Technical Specification Surveillance Requirement 4.1.1.1.1.e applies to MODES 3, 4, and 5 to properly consolidate the MODE 5 surveillance requirements.
In addition, proposed Technical Specification Bases 3/4.1.1.1 is amended to describe the bases for the boron dilution event minimum shutdown margin requirement as the limiting condition for MODE 5 (T 1200*F). The proposedTechnicalSpecifications,includingchangeskntheIndex,are av shown in Attachment A of' this LCA.
REASON FOR CHANGE This License Change Application (LCA) incorporates a Technical Specification change to the MODE 5 shutdown margin. This Technical Specification change is in response to the NRC letter dated September 30, 1980 concerning the consequences of an inadvertent boron dilution event during MODES 4 and 5.
The PGE analysis concluded that return to criticality due to a boron dilution event will not occur for the Trojan Nuclear Plant, as current available shutdown margins preclude this trom happening (see Figure 1).
However, the Technical Specification shutdown margin requirement plus stuck rod, worth will not guarantee an adequate sl u. down margin for a boron dilution event during MODE 5 operation. Theref ore, PCE committed in its response to the NRC dated November 26, 1980 to submit this Technical Specification revision changing the MODE 5 shutdown margin from 1.0 per-cent ak/k to 1.6 percent ak/k to ensure that minimum shutdown margin requirements are met.
Inis LCA modifies the Technical Specifications to complete this commitment.
SAFETY EVALUATION The proposed Technical Specification changes have been reviewed and
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determined to not constitute an unreviewed safety question. These changes are required in order to assure that return to criticality is not a concern for a postulated boron dilution event during MODE 5 operation.
No new accidents are created, and the probability of occurrence of accidents already considered remains unchanged. Since these Technical l
Specification changes increase the minimum shutdown margin requirement for MODE 5, the potential for and/or consequences of an accident are l
reduced or remain unchanged. The proposed changes do not impact previ-ously evaluated environmental considerations and do not pose an unreviewed environmental question.
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LCA 71 Page 2 of 3 SCHEDULE CONSIDERATIONS TOis LCA is submitted in response to the NRC letter dated September 30, 1980. The PCI response dated November 26, 1980 committed to substt the License Change I,pplication prior to or on March 1, 1981. Internal peccessing of this application was delayed due scheduli.7g difficulties, however, the 180 day submittal deadline is still met.
_ BASES FOR DETERMINATION OF AMENDMENT CLAUSE This LCA will result in a License Amendment involving a single complex issue that is clearly defined by an NRC position and would not involve significant hazards consideration. Thus, this would be a Class III amendment.
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I IAllRodsin ShutdownMarginl
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l% All Rods in Shutdown 1400r I(Proposed Tech Mode 4-Temperature Spec Change for Margin (Tech Spec IMode 5 Plus Stu k
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1,imit of 350*F Requirement for Mode 5 1300-gRodWorth) 4 Plus Stuck Rod Worth)
Mode 5-Temperature
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1.imit of 200*F l
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1200-l S
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g 1100-8 I
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g 1000-i i
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=e 900-All Rods in Shutdown S
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Margin Available for Mode 5 l
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g 800-8 g
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Margin (Tpch Spec
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g9 Requiremeat for Mode 4 y
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500-
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Dilution Flow Shutdown i
Ma. gin Available for tiargin Requiremer'st r
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l 400-I g
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100-3 O. 9(>
O!97 O!98 Shutdown Margin in Terms of Initial k gg, Figure 1 Shutdown Margin Requirements and Availability for a Boron Dilution Accident at Trojan l
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