ML20203C577

Responds to Request for Addl Info on Generic Ltr 84-04 Re Improvements to SEP Seismic Spectra Program for Reactor Cavity Pool Seal Design.Plan of Action for Seismic Analysis Will Be Provided by 860709

ML20203C577
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	04/11/1986
From:	Opeka J CONNECTICUT YANKEE ATOMIC POWER CO.
To:	Charemagne Grimes Office of Nuclear Reactor Regulation
References
A05457, A5457, GL-84-04, GL-84-4, NUDOCS 8604210195
Download: ML20203C577 (3)

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CONNECTICUT Y ANKEE ATOMIC POWER COMPANY B E R L I N. C O N N E C Tic U T P o BOX 270 HARTFoAD CONNECTICUT 06141-0270 TELEPHONE 2oses-sooo April 11,1986 Docket No. 50-213

. A03457 Office of Nuclear Reactor Regulation Attn: Mr. Christopher 1. Grimes, Director Integrated Safety Assessment Project Directorate Division of PWR Licensing - B U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Gentlemen:

Haddam Neck Plant Response to Request for Additional Information on Generic Letter 84-04 In a meeting summary on the new design of the reactor cavity pool sealil) a response was requested to the question:

How does in identified theGeneric HaddamLetter Neck 84-04 plant p(r_qpose a with thetoSystematic satisfy the two conditions Evaluation Program (SEP) seismic spectra, including a description of the improvements planned to specific supports?

In a previous letter,(3) a response was provided with the exception that a description of the improvements planned to specific supports was not discussed.

To summarize that discussion and provide further clarification, a restatement of the two conditions of Generic Letter 84-04 followed by a statement addressing those conditions is provided below.

(1) F. Akstulewicz letter to Northeast Utilities, " Meeting Summary on New Design of the Reactor Cavity Pool Seal," dated December 17,1985.

(2) D. G. Eisenhut letter to All Operating PWR Licensees, Construction Permit Holders and Applicants for Construction Permits, " Safety Evaluation of Westinghouse Topical Reports Dealing with Elimination of Postulated Pipe Breaks in PWR Primary Main Loops (Generic Letter 84-04), dated February 1, 1984.

(3) 3. F. Opeka letter to 3. A. Zwolinski, New Design of the Reactor Cavity Pool Seal, dated November 7,1986.

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Condition 1 Confirm the results of seismic analysis show that the maximum bending moments do not exceed 42,000 in-kips for the highest stressed vessel nozzle / pipe junction.

Response

Using the SEP seismic spectra, Westinghouse performed a plant-specific analysis of the reactor coolant system piping stresses. It was determined that at the highest stressed vessel nozzle pe junction, the maximum bending moment would not exceed 35,255 in-kips provided no support failures occur. This was done to support the leak before break philosophy and demonstrate that WCAP-9558 was applicable. In performing this seismic analysis, Westinghouse also identified required reactor coolant system modifications, subsequent to assuring us that WCAP-9358 was applicable. These modifications were in turn identified in the NRC's Safety Evaluation of the SEP, Topic 111-6.(5)

In order to ensure the first condition of Generic Letter 84-04 is met considering the SEP seismic event, and to resolve SEP Topic 111-6 open items with respect to the reactor coolant system, we are currently performing detailed engineering, design and procurement activities on a schedule which will allow modifications to the steam generator hold-down bolts, reactor coolant pump hangers, pressurizer truss, and surge-line support during the 1987 refueling outage. These modifications are based upon analyses and design reports received from Westinghouse to date.

Due to recent developments in industry knowledge of seismic analysis methodologies culminating in recommendations provided within NUREG-1061 and of the Pressure Vessel Research Council (PVRC), we do plan to review the existing analysis methodologies and acceptance criteria and ultimately reassess the need for performing these modifications. A plan of action, including proposed analytical techniques for this re-evaluation, will be submitted by July 9,1986.

Connecticut Yankee Atomic Power Company, in keeping with previous verbal commitments, will transmit Westinghouse reactor coolant system seismic evaluation reports that were done as part of the original SEP seismic evaluation by July 9,1986. It should be noted that these will be submitted along with our plans for re-evaluation discussed above. Results of the re-evaluations and final plans for modifications will be reported to the NRC in January of 1987. Actual installation of the modifications determined necessary is planned to be performed during the 1987 refueling outage provided it is consistent with schedular priorities established during the ISAP program for the Haddam Neck Plant.

(4) W. G. Counsil letter to D. M. Crutchfield, dated June 8,1983, documented results of the plant-specific analysis.

(5) D. M. Crutchfield letter to W. G. Counsil, dated February 25,1983.

Condition 2 Leakage detection systems at the facility should be sufficient to provide adequate margin to detect the leakage from the postulated circumferential through-wall flaw utilizing the guidance of Regulatory Guide 1.45, " Reactor Coolant Pressure Boundary Leakage Detection Systems," with the exception that the seismic qualification of the airborne particulate radiation monitor is not necessary. At least one leakage detection system with a sensitivity capable of detecting I gpm in 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> must be operable.

Response

The Integrated Plant Systematic Assessment Report (IPSAR) for the Haddam Neck Plant, Sections 4.16.1 and 2, evaluated leakage detection systems and corresponding operability requirements. As a result of these evaluations and commitments made during the meeting on the new Reactor Cavity Pool Seal (6),

a license amendment request will be forwarded prior to start-up. The proposed change will place Technical Specification requirements on reactor coolant system leakage detection systems such that operability and surveillance requirements are specified. The systems covered in the Technical Specifications include the Gaseous Radioactivity 4.onitoring System, the Containment Main and Instrument Sump Level Monitoring System, and the Volume Control Tank (VCT)

Level Monitoring System which is being used to determine unidentified leakage in conjunction with a reactor coolant system inventory balance. The VCT is being relied on to meet leakage detection sensitivity requirements of Generic Letter 84-04 with the Main and Instrument Containment Sump Level Monitoring Systems used as backups. Section 4.16.4 of the IPSAR pointed out that the use of reactor coolant inventory balance to determine RCS leakage is an acceptable alternative to " leakage detection" systems. To ensure operability following a seismic event greater than one half the Safe Shutdown Earthquake (SSE), a channel calibration of the VCT Level Monitoring System will be required subsequent to such an event. Condition 2 will be met with this Technical Specification and additionally, the SEP open items on leakage detection systems should be fully resolved.

We trust the above information is responsive to your request and will provide additional information in accordance with the plans outlined above.

Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY b bu_[L-

3. F. Op'eka) U Senior Vice President (6) F. Akstulewicz letter to Northeast Utilities, " Meeting Summary on New Design of the Reactor Cavity Pool Seal," dated December 17,1985.