ML20044G869
| ML20044G869 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/28/1993 |
| From: | Opeka J, Romberg W NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20044G870 | List: |
| References | |
| B14491, NUDOCS 9306040373 | |
| Download: ML20044G869 (2) | |
Text
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i NORTHEAST UTILITIES cenere Off ces. seiden street, seriin Connecticut i
5.
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HARTFORD. CONNECTICUT 06141-0270 i
I L IJ Zj[][7" (203) 665-5000 l
May 28, 1993 i
Docket No. 50-245 B14491 Re:
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U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Millstone Nuclear Power Station, Unit No. 1 Proposed Revision to Technical Specifications Pressure-Temperature Limit Curves Sucolemental Information In a letter dated March 22, 1993,"' pursuant to 10CFR50.90, Northeast Nuclear Energy Company (NNECO) proposed to amend its Operating License,.No. DPR-21, by incorporating changes described in the letter into the
. Technical Specifications of Millstone Unit No. 1.
The proposed changes revised the pressure-temperature (PT) limits for. the Millstone Unit No. I reactor pressure vessel (RPV).
The current ~ limitations are valid to 16 effective full power years (EFPY), most recently calculated 'to be reached on June 18,1993- (assuming continued - full power operation).
The revised PT limits have been calculated in order to continue operation beyond 16 EFPY.
The proposed limits reflected the predicted radiation-induced embrittlement of the RPV through 32 EFPY.
During telephone discussiens regarding the March 22, 1993, request, the NRC Staff questioned the method used to incorporate the results ' of the surveillance capsule testing' into the 10CFR50 Appendix G PT limit curves.
Specifically, the Staff questioned the methodology used to differentiate-between the bulk and local material chemical composition. The method utilized-assumed the chemical composition of the limiting vessel plate to be:the same as the chemical composition provided for the plate heat number and assumed the chemical composition of the Charpy specimens to be the same as. the chemical
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composition of the two surveillance specimens tested during the surveillance capsule evaluation.
1he Staff did not concur with this approach, since the Charpy specimens were obtained from the limiting plate and only.two specimens-were tested during the surveillance capsule evaluation.
This differentiation is appropriate to account for the chemical variability throughout the. plate.
1 (1)
J.
F.
Opeka letter to U.S.
Nuclear Regulatory Commission, " Proposed i
Revision to Technical Specifications--Pressure-Temperature Limit Curves,"
dated March 22, 1993.
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l U.S'. Nuclear Regulatory Commission B14491/Page 2 I
May 28, 1993 This conservative approach resulted in a reference temperature for. nil ductility transition (RTuor) increase of approximately 7-11*F.
As such, the PT limit curves have been modified to incorporate the increase in the RTuor.
This change results in minimum hydrostatic and leak test i
temperatures which exceed the boiling point of water and therefore it will have a potential impact on plant operations, personnel safety, and equipment reliability.
For this reason, NNECO indicated to the Staff that although it would incorporate their comments in order to expedite the review of the license amendment request (i.e., current curves expire on June 18, 1993),
NNEC0 most likely would revisit this issue in the future to resolve the NRC concerns without increasing the calculated RTuor.
The Staff concurred with this approach.
The revised PT curves are provided as Attachment I and supersede those that i
were provided in the March 22, 1993, submittal.
We note that the discussion regarding the finding of no significant hazards consideration provided in the March 22, 1993, submittal remains valid with the changes to the PT curves.
If you have any questions, please contact us.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY FOR: J. F. Opeka Executive Vice President OO lLV gy.
a W. D. Romberg>
Vice President cc:
T. T. Martin, Region I Administrator J. W. Andersen, NRC Project Manager, Millstone Unit No. 1 i
P. D. Swetland, Senior Resident Inspector, Millstone Unit Nos.1, 2, and 3 i
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