ML20063N163

Forwards Info Re SER Outstanding Issue 6, Steady State Vibration Acceptance Criteria for Balance of Plant Piping. Piping Sys Will Be Evaluated by Measuring Displacement Amplitudes

ML20063N163
Person / Time
Site:	Clinton
Issue date:	09/15/1982
From:	Wuller G ILLINOIS POWER CO.
To:	Thomas C Office of Nuclear Reactor Regulation
References
U-0543, U-543, NUDOCS 8209200039
Download: ML20063N163 (2)

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U-0543 ILL/NOIS POWER 00MPANY y L39_ggz99_z5y5 500 SOUTH 27TH STREET, DECATUR, ILLINOIS 62525 September 15, 1982 Mr. Cecil 0. Thomas, Branch Chief Standardization & Special Projects Branch Division of Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Thomas:

Clinton Power Station Unit 1 Docket No. 50-461

Reference:

1) IP Letter U-0477, dated 5/10/82, from G. E. Wuller to J. R. Miller,

2) NRC Letter, dated 6/29/82 from R. E. Carter to G. E. Wuller.

This letter provides information regarding CPS-3ER Outstanding Issue No. 6 on " Steady State Vibration Acceptance Criteria for BOP 1

Piping", (Section 3.9.2). -

The reference letter no. 1 transmitted to the Staff the draft of the ASME Standard, OM-3, showing ASME Committee approval of the 80% endurance limit (S from Appendix I of the ASME Code on steady-state vibration acc8p)tance criteria from BOP Piping.

Reference letter no. 2 stated that the Staff required further technical justification for use of this criteria. The purpose of this letter is to provide such technical justification.

It is IP's position that the use of the 80% endurance limit criteria is acceptable. The justification for this position, as supported by the NRC consultant E. C. Rodabaugh, is as follows:

The allowable stress amplitude, S used for steady state piping vibration is equal t0 80% 6 of the alternating stress intensity at 10 cycles for carbonsteelsandto6g%ofthealternating stress intensity at 10 cycles for stainless steels. The values of alternating stress in-tensity are taken from Figure I-9.1 of Appendix 1, ASME Code Section III. In addition, a " factor of safety" of 1.3 is applied to the allowable stress amplitudes when detailed evaluation methods are used to determine the vibratory stresses.

When simplified evaluation methods are used, there is sufficient conservatism in the methods to account for the factor of safety.

DO K O hh PDR

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U-0543 L30-82(09-15)6 l September 15, 1982 l Page #2 l Therefore, considering the factor of safety, l the allowable stress amplitudes used are as follows:

a = 0.8 x 12,500/1.3 = 7,690 psi for carbon S

steels with UTS 80 ksi S

= 0.6 x 26,000/1.3 = 12,000 psi for i

stainless steels.

In addition, CPS-FSAR Table 3.9-13 and Section 3.9.2.1.4.1 indicate the vibration of the piping system will be evaluated by measuring the displacement amplitudes.

IP believes that the above information provides adequate justification for closing this issue. IP intends to incorporate this information into the CPS-FSAR in the near future. If you.

should have any further concerns, we stand ready to meet with'your staff at their earliest convenience so that this issue can be closed out as expeditiously as possible.

Sincerely, l

,.- i .

G. E. Wuller Supervisor-Licensing Nuclear Station Engineering TLR/ja cc: J. H. Williams , NRC Clinton Proj ect Manager H. H. Livermore, NRC Resident Inspector Dave Terao, NRC Mechanical Engineering Branch Illinois Dept. of Nuclear Safety

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