ML19343B826

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Requests Permission to Use 1977 ASME Code,In Addition to 1971 ASME Code,To Analyze Class 1 Chemical & Vol Control Sys Pump Seal Injection Line & Class 1 Pressurizer Pressure Relief Lines
ML19343B826
Person / Time
Site: Summer South Carolina Electric & Gas Company icon.png
Issue date: 12/19/1980
From: Nichols T
SOUTH CAROLINA ELECTRIC & GAS CO.
To: Harold Denton
Office of Nuclear Reactor Regulation
References
NUDOCS 8012300637
Download: ML19343B826 (2)


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m u. c <e.. December 19, 1980

>!r. Harold R. Denton, Director Office of Nuclear Reactor Regulation l'. S. Nuclear Regulatory Commission W ahington, D. C. 20555

Subject:

Virgil C. Summer Nuclear Station Docket No. 50/395 Acceptance of a Later Ccie Addenda

Dear !!r. Denton:

The purpose of this letter is to request permission to use later codes and addenda for the purpose of analyzing the class 1 CVCS Pump Seal Injection line and the class 1 Pressurizer Pressure Relief lines.

The 1971 AS!!E Code (including addenda) provided no class 1 exceptions for either small bore pipe or for systems experiencing only mild ther=al transients.

The Code did, however, include in NB 3630(d) the statement "for small bore piping, alternate design rules are in course of preparation", indicating that the class 1 rules would probably be modified for some piping systems as more class 1 experience was gained. The Summer 1975 addenda was the first to provide relaxation for the analysis of class 1 piping by allowing 1-inch nominal pipe size and less to be de-signed in accordance with class 2 rules. The Summer 1976 addenda then gave additional exemptions for any class 1 piping which could meet the requirem,entc (a) through (e) of NB-3630(d) (2). We have determined that the five exemptions apply for the CVCS Pump Seal Injection line and are therefore, requesting that SCE&G be allowed to use 1974 AS!!E Code - Summer 1976 addenda for its analysis.

The 1977 AS3fE Code - Summer 1979 addenda addresses how the linear portion of the radial temperature gradient should be considered. This latest code philosophy reflects a better approach to provide protection from thermal

( ratcheting. SCE&G, therefore, requests that the analysis for the Pressurizer Pressure Relief lines be performed according to the applicable 1971 AS!1E Code except that with respect to the linear radial gradient stress, the 1977 AS!!E Code - Summer 1979 addenda be employed.

These two changes in code of record will result in a significant savings in l

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s Mr. Harold R. Denton -

December 19, 1980 Page 2 time and effort for our "as-built" re-analysis program. Accordingly, we wish to obtain your approval as soon as possible in order to continue our program.

Very truly yours, t k, T. C. Nichols, Jr.

GDM:TCN:glb cc: V. C. Summer G. H. Fischer T. C. Nichols, Jr.

E. H. Crews, Jr.

O. W. Dixon, Jr.

D. A. Nauman

0. S. Bradham W. A. Williams, Jr.

A. A. Smith A. R. Koon R. B. Clary J. B. Knotts, Jr.

J. L. Skolds B. A. Bursey NPCF/Whitaker File

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