B11875, Submits Addl Info Re 850502 Application to Revise Tech Spec Section 4.10,Item D Re Reactor Vessel Surveillance Capsule Removal Frequency,Per Request.Analysis of Capsules Removed Show That Embrittlement Comparable to Industrial Trends

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Submits Addl Info Re 850502 Application to Revise Tech Spec Section 4.10,Item D Re Reactor Vessel Surveillance Capsule Removal Frequency,Per Request.Analysis of Capsules Removed Show That Embrittlement Comparable to Industrial Trends
ML20137G684
Person / Time
Site: Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date: 11/14/1985
From: Opeka J
CONNECTICUT YANKEE ATOMIC POWER CO.
To: Zwolinski J
Office of Nuclear Reactor Regulation
References
B11875, NUDOCS 8512020234
Download: ML20137G684 (2)


Text

e CONNECTICUT YANKEE ATOMIC POWER COMPANY B E R L I N. CO NN E C TIC U T P O box 270 HARTFORD. CONNECTICUT 06141-0270 Y ELEPHONE 203 4 65-5000 November 14, 1985 Docket No. 50-213 Bil875 Director of Nuclear Reactor Regulation Attn: Mr. John A. Zwolinski, Chief Operating Reactors Branch #5 U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Reference:

(1) W. G. Counsil letter to D. M. Crutchfield, dated May 2,1985.

Gentlemen:

Haddam Neck Plant Informational Letter on Surveillance Capsule Removal Frequency included in the proposed revisions to Technical Specifications forwarded in Reference (1) was a change to Section 4.10, item D, on reactor vessel surveillance capsule removal f requency. In that revision we proposed to change the removal time of Capsule E from 25 years to a " Standby" status. During subsequent conversations with the NRC Staff additional information was requested on the justification and basis for this change. We have concluded that an adequate basis exists for placing Capsule E into a standby status and per your request a more thorough discussion of our basis is provided below.

The most recent capsule removed was Capsule D. This capsule was irradiated to a fluence of 2.22 (1019) neutrons /cm2 which is comparable to the limiting predicted vessel 1/4T fluence of 2.7 (1019) neutrons /cm2 at 27 elfective full power years (E > 1 MeV).(l) Analysis of capsules removed thus far have shown that embrittlement is comparable to the trends the industry has experienced for similar fluence levels and copper and nickel content. Also, the fluence levels have compared well with those predicted when corrected for actual versus design basis fuel loading. Bec :use of these findings we believe the amount of embrittlement which will be experienced over the 40 year design life of the vessel is well understood.

(1) W. G. Counsit letter to H. R. Denton, dated July 6,1933, forwarding the report entitled, " Analysis of Capsule D from the Connecticut Yankee Reactor Vessel Radiation Surveillance Program."

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Capsule E is the only one of the remaining capsules that consists of beltline weld material which is most limiting because of its copper and nickel content. Our intent for that capsule, as well as those remaining in standby, is to hold them in reserve so they may be analyzed in the future in support of continued operation beyond the 40 year design life of the pressure vessel. We believe the value of the data gained by doing so far outweighs that which would be gained by removing Capsule E at 25 years.

Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY

h. . F. CA
3. F. Opfhd L Senior Vice President I

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