ML20149M724

Discusses SEP Topic III-6, Reactor Pressure Vessel/Neutron Shield Tank Seismic Response & Amplified Response Spectra. Util Plans No Further Action on Matter & All Efforts to Engineer Plant Mod Suspended

ML20149M724
Person / Time
Site:	Yankee Rowe
Issue date:	02/18/1988
From:	Papanic G YANKEE ATOMIC ELECTRIC CO.
To:	Fairtile M NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM), Office of Nuclear Reactor Regulation
References
TASK-03-06, TASK-3-6, TASK-RR FYR-88-21, NUDOCS 8802290009
Download: ML20149M724 (2)

Text

. 9 l

,- Telephono I617) 8F2 8100 e

VWX F10-380 7619 YANKEE ATOMIC ELECTRIC COMPANY

. +

y 1671 Worcester Road, Framingham, Massachusetts 01701

% i February 18, 1988 FYR 88-21 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Attention: Mr. Morton Fairtile Project Directorate I-3 Division of Reactor Projects I/I'

References:

(a) License No. DPR-3 (Docket No. 50-29)

(b) Letter, YAEC to NRC (FYR 88-01), dated January 4, 1988 (c) Letter, NRC to YAEC (NYR 87-142), dated July 16, 1987

Subject:

SEP Topic III-6, Reactor Pressure Vessel / Neutron Shield Tank Seismic Response and ARS Generation

Dear Sir:

In order to resolve the issue of Reactor Pressure Vessel (RPV) sliding under NRC spectrum seismic loads, Yankee generated new Amplifiec Response Spectra (ARS) using new synthetic time histories and a revised Reactor Support Structure (RSS) model (Reference (b)). The evaluation conclusively demonstrated that the RPV would neither uplift nor slide under NRC seismic spectra loads. Also, based on the favorable results of the evaluation, Yankee plans no further action on this matter and has suspended all efforts to engineer n plant modification.

We also stated in that letter that we intended to use these new ARS for the evaluation of piping inside the vapor container. The reason for our decision to use these new ARS is that they are derived from a synthetic time history which has a better fit to the target NRC site-specific spectra than the synthetic time history used to derive the ARS generated in 1986.

The 1986 ARS have been approved by the staff in the SEP Topic III-6 SER, Reference (c).

Both the 1986 and the new ARS fully conform to the guidelines in SRP 3 7.1 and are otherwise acceptable. We recognize, however, that the staff is just beginning their review of our RPV sliding evaluation and has not yet approved our new ARS. Since Yankee is now beginning the seismic evaluation of piping, we will use the ArS generated in 1986 for that piping work.

l fl

[,

8802290009 880218 1 PDR ADOCK 05000029 P., RD

• 1 r

a United States . Nuclear Regulatory Commission February 18, 1988 Attention: Mr. Mortin Fairtile- Page 2 FYR 88-21 Yankee will retain the option of requesting staff approval for use of the new ARS to evaluate piping and equipment. This request would be made after the staff has approved the ARS for use in the evaluation of RPV uplift and sliding.

-Very truly yours,-

G. Pa nic, Jr. r)

Senior Project Engineer Licensing GP/gbo cc: USNRC Region I USNRC Resident Inspector, YNPS F

f h

1 F

h l

.i 1

l i

._ .- . -