B12069, Comments on Proposed Rev 2 to Reg Guide 1.99, Radiation Damage to Reactor Vessel Matls, Issued Feb 1986.Two Areas Re Attenuation Formula & Surveillance Data Section Should Be Reconsidered.Proposed Addition Re Subj Data Section Encl

Comments on Proposed Rev 2 to Reg Guide 1.99, Radiation Damage to Reactor Vessel Matls, Issued Feb 1986.Two Areas Re Attenuation Formula & Surveillance Data Section Should Be Reconsidered.Proposed Addition Re Subj Data Section Encl

ML20204A508
Person / Time
Site:	Millstone, Haddam Neck, 05000000
Issue date:	04/28/1986
From:	Opeka J CONNECTICUT YANKEE ATOMIC POWER CO., NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Randall P NRC OFFICE OF ADMINISTRATION (ADM)
References
RTR-REGGD-01.099, RTR-REGGD-1.099 B12069, NUDOCS 8605120293
Download: ML20204A508 (3)

Text

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H ARTFORD. CONNECTICUT 06141-0270 k L J $.7.[ $*Cf.Y.*Z (203) 66s-5000 April 28,1986 Docket Nos. 50-213 50-245 50-336 50-423 B12069 Office of Nuclear Regulatory Research Attn: P. N. Randall Rules and Procedures Branch Division of Rules and Records U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Gentlemen:

Haddam Neck Plant Millstone Nuclear Power Station, Unit Nos.1,2, and 3 Comments on Proposed Revision 2 to Regulatory Guide 1.99 In February of 1986 a proposed revision to Regulatory Guide 1.99, " Radiation Damage to Reactor Vessel Materials" was issued. Connecticut Yankee Atomic Power Company (CYAPCO), licensee for the Haddam Neck Plant, and Northeast Nuclear Energy Company (NNECO), licensee for Millstone Unit Nos.1,2, and 3 are taking this opportunity to provide comments on the proposed revision to the Regulatory Guide.

In general, we believe that Revision 2 incorporates more accurate methods of predicting radiation damage to reactor vessel materials and represents a significant improvement over Revision 1. However, two specific areas should be reconsidered.

o The attenuation formula (equation (3))is based on and is only accurate for a fluence of 1019 n/cm2 Below this value (for BWR's) it is conservative and above this value (for PWR's), it is non-conservative. Fluence values for a given vessel wall depth should be attenuated prior to A RTNDT computations for the reference temperature.

o The surveillance data section does not prevent or require any consideration of the testing results of the first surveillance capsule. Consideration should be given to each surveillance capsule. Attachment 1 is a proposed addition to the proposed Regulatory Guide.

With respect to the draf t regulatory analysis section, this is essentially a value-impact analy)(2)(3) for BWR's.(1 sis for the guide's effect on typical PWR's. This analysis is not valid For BWR's, adoption of this Regulatory Guide (in conjunction with existing regulations) will require hydrostatic and leak testing to be performed at a higher tempera ture. This will lengthen plant outages, increase occupational exposure and reduce worker safety.

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Further, it is not clear that the risk of public exposure would be reduced by this change. Higher temperature tests are less likely to find critical flaws. Thus, the chance of failure during the test is reduced but the protection against an operational f ailure is also reduced.

In view of +.hese facts, the NRC should consider a fourth alternative in its regulatory analysis. This alternative would implement the guide as is, but would allow testing with a safety factor of 1.5 against K IC instead of KIR. Significant costs would then be eliminated without any clear change in public risk.

We appreciate this opportunity to provide comments on this draf t revision to Regulatory Guide 1.99 and are available to provide any further clarification if required by the Staff.

Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY NORTHEAST NUCLEAR ENERGY COMPANY J. F. Opeka

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V Senior Vice President (1) Letter, BWROG-8534, BWR Owners' Group (J. M. Fulton) to U.S. Nuclear Regulatory Commission (V. Stello), " Proposed NRC Revision of R.G.

1.99/ Potential Impact on BWRS", dated August 12,1985.

(2) Letter, BWROG-8548, BWR Owners' Group (3. M. Fulton) to U.S. NRC (V. Stello), " Proposed NRC Revision of R.G. 1.99/BWR Value Impact System", dated October 9,1985.

(3) Letter, BWROG-8613, BWR Owners' Group (3. M. Fulton) to U.S. NRC (P. N. Randall), "BWR Owners' Group Evaluation of Regulatory Guide 1.99, Revision 2 Impact on BWRS Part 1, NEDC-3-ll40".

n-Attachment 1 Proposed Addition to Regulatory Guide 1.99, Rev. 2

2. Surveillance Data Available All available surveillance test data should be compared to an appropriately predicted mean shif t obtained by the method described in Part C.1 of this guide. If the surveillance test shift differs from the predicted shift by more than two standard deviations, appropriate adjustments should be made.

When two or more...

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