ML20042F993
| ML20042F993 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 05/07/1990 |
| From: | Walt T PORTLAND GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20042F987 | List: |
| References | |
| NUDOCS 9005100272 | |
| Download: ML20042F993 (4) | |
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i PORTLAND CENERAL ELECTRIC COMPANY EUGENE WATER & ELECTRIC BOARD AND
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PACIFIC POWER & LICitT COMPANY J
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l Operating License NPF-1 t
Docket 50-344 j
License Change Application 197 j
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.This License Change Application (LCA) revises Trojan Technical Specifi-l cation (TTS) 3.1.3.4, " Shutdown Rod Insertion Limit" Figure 3.1-1, " Rod
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i Bank Insertion Limits Versus Thermal Power - Four Loop Operation" and Figure 3.1-2, " Rod Bank Insertion Limits Versus Thermal Power - Three Loop Operation" to define fully withdrawn rods as >223 steps.
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PORTLAND CENERAL ELECTRIC COMPANY
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By
' T. D. Walt Acting Vice President Nuclear Division 5
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Subscribed and sworn to bnfore me this 7th day of May 1990.
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Notdry Public#ol fregon M/
My Commission Rxpirost
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9005100272 9005o7 hDR ADOCK 05000344 PDC
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4 LCA 197 Attachment A l
page 1 of 6 Description of Channo This change revises Trojan Technical Specifications (TTS) 3.1.3.4
" Shutdown Rod Insertion Limit". Figure 3.1-1, " Rod Bank Insertion Limits Versus Thermal power - Four Loop Operation" and Figure 3.1-2, " Rod Bank Insertion Limits Versus Thermal power - Three Loop Operation" to defino fully withdrawn rods as >223 steps, p
Reason for Change L
h An Electric power Roccarch Institute (EPHI) study (Reference 1) concluded I
that control rod lifetimes can be extended if localized mechanical fretting wear can be distributed over the rod. The wear is caused by flow-induced vibration of the control rod against the guide tube alignment cards. Over a long period of time with the same portion of the rod exposed to the alignment cards, the fretting wear could result in breaching the control rod cladding and impairing the rod's movement into the core. To minimize the potential for this type of wear, portland General Electric Company (pCE) requested [via License Chango Application (LCA).146 dated October 31 _1986) and received approval (in Amendmont 125 dated March 20, 1987) to change the fully withdrawn rod pesition from 228 to 226 steps.
pGE now finds it desirable to contlaue to prolong control rod life by once again changing the position of the rod.
Determination of Significant Hazards Consideration in accordance with the requirements of Title 10. Codo of Federal Regulations, part 50.92 (10 CFR 50.92), this LCA is judged to involvo no significant hazards based upon the following information:
1.
Does the proposed license chango involvo a significant increase in the probability or consequences of an accident?
Rod ~1nsortion limits are established to ensure that power distribution limits are met and the minimum shutdown margin is maintained. Since the proposed change does not'chango the insortion limit,.it does not offect TTS 3/4.2, " Power Distribution Limits" or
.TTS 3.1.1.1, " Shutdown Margin".
For the Cycle 12 Reload Report (Reference 2), the fully withdrawn position was calculated using the 224 steps position and shown to have a shutdown margin in excess of the required margin used in the accident analysis. Reference 2 further concluded that using the 224 steps position or higher does not impact the accident analysis and as such the probability or consequences of an accident is not increased.
2.
Does the proposed license change create the possibility of a new or different kind of accident from any accident previously analyzod?
i LCA 197 f
Attachment A page 2 of 6 A new or different kind of accident is not created since as discussed above, the power distribution limits and shutdown margins continue to be maintained.
3.
Does the proposed license change involvo a significant reduction in a margin of safety?
There is negligible impact upon the power distribution and shutdown margin because of the low rod worth in the top region of the core.
There is sufficient shutdown margin to accommodato the all rod out position (ARO) to 224 steps for Cycle 12.
Referenco 2 calculates a reactivity penalty of.07 porcent op for the proposed change.
Since the available shutdown margin was 2.06 and 1.99 for Cycles 11 and 12 respectively versus the required margin of 1.60, the.07 penalty can be easily accommodated. Likewise sufficient peaking factors and Departuro from Nucleate Boiling Ratio (DNBR) margins are available to accommodate the negligible effect on power distribution.
Therefore, the proposed change does not-significantly reduce a margin of safety.
In the March 6, 1986 Federal RoRister, the Nuclear Regulatory Commission (NRC) published a list of exanples of amendments that are not likely to involve a significant hazards consideration.
Example (vi) from this list states:
"A chauso which either may result in some incrosso to the probability or consequences of a previously analyzed accident or may reduce in some way a safety margin, but where the results of the chango are clearly within all acceptable criteria with respect to the system or component.specified in the Standard Review plan, e.g.,
a change resulting from the application of a small refinomont of a previously used calculational model or design method."
Because the proposed change is similar to this examplo, it does not pose a significant hazard.
Safety / Environmental Evaluation Safety and environmental evaluations were performed as required by 10 CFR 50 and the TTS.
The review determined that the proposed change does not creato an unreviewed safety question, nor does it create an unreviewod environmental question.
Schedule Considerations It is requested that the effective date of the amendment be 30 days after issuanco by the NRC.
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LCA 197 Attachment A Page 3 of 6 REFERENCES 1.
EPRI NP-4512. " Lifetime of PWR Silver - Indium - Cadmium Control Rods", March 1986.
2.
Westinghouse Report, " Reload Safety Evaluation Trojan Cycle 12",
May 1989.
KBR/4733W