B12248, Forwards Reviews for Isap 1.04, Seismic Qualification of Safety-Related Piping, Isap 1.50, Fracture Toughness of Supports & Isap 1.56, Bolting Degradation, in Accordance W/Jf Opeka

Forwards Reviews for Isap 1.04, Seismic Qualification of Safety-Related Piping, Isap 1.50, Fracture Toughness of Supports & Isap 1.56, Bolting Degradation, in Accordance W/Jf Opeka

ML20215N669
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	10/27/1986
From:	Opeka J CONNECTICUT YANKEE ATOMIC POWER CO.
To:	Charemagne Grimes Office of Nuclear Reactor Regulation
References
B12248, NUDOCS 8611070144
Download: ML20215N669 (9)

Text

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CONNECTICUT YANKEE ATOMIC POWER COMPANY B E R L I N. CONNECTICUT P o BOX 270 HARTFORD. CONNECTICUT 06141-0270 TELEPHONE 203-665-5000 October 27,1986 Docket No. 50-213 B12248 Office of Nuclear Reactor Regulation Attn: Mr. Christopher I. Grimes, Director Integrated Safety Assessment Project Directorate Division of PWR Licensing - B U.S. Nuclear Regulatory Commission Washington, D.C. 20555

References:

(1) 3. F. Opeka letter to C. I. Grimes, dated May 17,1985.

(2) H. L. Thompson letter to 3. F. Opeka, dated July 31,1985.

Gentlemen:

Haddam Neck Plant Integrated Safety Assessment Program In Reference (1), Connecticut Yankee Atomic Pawer Company (CYAPCOf provided a proposed scope for the Integrated Safety Assessment Program (ISAP) review of the Haddam Neck Plant. In Reference (2), the Staff formally issued the results of the ISAP screening review process, establishing the scope of ISAP for Haddam Neck and initiating issue-specific evaluations. Reference (1) also indicated that for each issue or topic included in ISAP, CYAPCO would provide a discussion of the safety objective and an evaluation of the plant design with respect to the issue being addressed to identify specific items to be considered in the integrated assessment. In accordance with this commitment, reviews for the following ISAP topics are attached:

1) ISAP Topic No.1.04 " Seismic Qualification of Safety-Related Piping"

2) ISAP Topic No.1.50 " Fracture Toughness of Supports"

3) ISAP Topic No.1.56 " Bolting Degradation" If you have any questions concerning the attached reviews, please contact us.

Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY

3. F. Opera b bra-U Senior Vice President 8611070144 861027 i

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PDR ADOCK 05000213 p PDR

Docket No. 50-213 B12248 Haddam Neck ISAP Topic No.1.04 Seismic Qualification of Safety-Related Piping October 1986

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.. . -Haddam Neck ISAP Topic 1.04

. Seismic Qualification of Safety-Related Piping I. . 'ntroduction Assessment 'of safety-related issues for nuclear power plants has focused on' externally-initiated events as.well as internally-initiated events which can lead to core melt. A severe earthquake in the vicinity of a plant may result in a loss of offsite power and reactor trip. To bring the plant to a safe shutdown: condition, the decay heat removal systems as well as the diesel generators are required to be operable following the seismic event.

The decay' heat removal systems at the Haddam Neck Plant include the residual heat removal, service . water, chemical and volume control, and auxiliary feedwater systems. Severe. seismic events have the potential to cause piping failures in these critical decay heat removal systems. Lack of decay heat removal capability could result in core melt.

SEP Topic 111-6 requested that a program be initiated to demonstrate the seismic adequacy of the safety-related piping at the Haddam Neck Plant.

Based on the Staff's assessment of the original seismic design, the Haddam Neck Plant was placed in Group 11 for review. This required reanalysis of safety-related piping and supports to upgrade the seismic capability of the facility,to sustain a safe shutdown earthquake.

II. Review Criteria

~1. I&E Bulletin 79_-02 " Pipe Support Base Plate Designs Using Concrete Expansion Anchor Bolts"

2. I&E Bulletin 79-14 " Seismic Analysis for As-Built Safety-Related Piping Systems"

3. SEP Topic III-6; " Seismic Design Considerations" III. - Related Topics / Interfaces ISAP Topic No.1.05 ." Seismic' Structural Modifications" ISAP Topic No.1.08 " Seismic Modifications to Reactor Coolant System" ISAP Topic No.1.09 " Design Codes, Design Criteria, Load Combinations" ISAP Topic No.1.48 " Seismic Qualification of Equipment" IV. Evaluation In response to SEP Topic III-6, CYAPCO initiated an extensive reanalysis program to perform stress. analysis of safety-related piping systems using as-built piping Isometrics and support information developed under the I&E Bulletin 79-14 program.

2 The affected systems are as follows:

Main. Steam Main Feedwater Auxiliary Feedwater Residual Heat Removal Low Pressure Safety Injection High Pressure Safety Injection Chemical and Volume Control Service Water Emergency Diesel Generator Fuel Oil and Starting Air This effort included:

(a) Static stress analysis of these systems for weight, pressure and thermally-related loads, (b) Dynamic seismic analysis utilizing the Dynamic Response Spectra, and (c) Addition of supports and/or restraint modifications as determined by items (a) and (b) above.

Where necessary, the piping in these systems are fitted with new restraints or modifications are made to existing restraints to ensure that the piping ~

will remain functional following a safe shutdown earthquake (SSE).

Currently, a program for piping modifications is in place. There are approximately 160 supports remaining to be modified, of which approximately 100 are on the main steam and feedwater systems outside containment. The remaining supports are on the safety injection, residual heat removal, reactor . coolant, and service water systems. Additional pipehangers and equipment supports are candidates for upgrade during the 1987 refueling outage at the Haddam Neck Plant.

V. Conclusions As part of CYAPCO's ongoing commitment to seismic analysis, further evaluation of this topic will be undertaken in the integrated assessment.

VI. References

1. " Regulatory Analysis for Proposed Resolution of Unresolved Safety Issue A-46 Seismic Qualification of Equipment in Operating Plants,"

Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Attachment to NUREG-1030, August 1985.

2. " Report of the U.S. Nuclear Regulatory Commission Piping Review Committee," NUREG-1061, Volume 5, April 1985.

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~ 3. - 3. F. Opeka letter to 3. A. Zwolinski, " Safety Related Piping Seismic Qualification Program - Criteria Document," dated June 27,1985.

4. W. G. Counsil letter to D. M. Crutchfield, " Seismic Reevaluation Program, SEP TOPIC 111 Seismic Design Considerations," dated June 11,1981.

Docket No. 50-213 B12248 Haddam Neck ISAP Topic No.1.50 Fracture Toughness of Supports October 1986

Haddam Neck ISAP Topic No.1.50 Fracture Toughness of Supports (USI A-12)

1. Introduction A lack of adequate toughness which may be caused by the combination of low operating temperature, presence of' flaws in the material, and non-

- redundancy of critical support members could result in failure of steam generator and reactor coolant pump structures under postulated (especially loss-of-coolant accident and earthquake) conditions. The concerns by the Staff and CYAPCO addressed the adequacy of the fracture toughness properties of the materials used to fabricate these supports. The question of failure due . to lamellar tearing has been resolved by the Staff in NUREG-0577.

[ II. Review Criteria NUREG-0577, Rev. 1 - " Potential for Low Fracture Toughness and

, Lamellar Tearing in PWR Steam Generator and Reactor Coolant Pump l Supports" III.- Related Topics / Interfaces ISAP Topic No.1.56 " Bolting Degradation"

! IV. Evaluatien A plant-specific assessment of the Haddam Neck Plant was performed in accordance with th~e recommendations outlined in NUREG-0577 Rev.1. It was determined that this issue was not_ a major concern at Haddam Neck, and no extensive fracture mechanics evaluations were necessary.

l V. Conclusions Based on the above, CYAPCO . considers this ISAP topic adequately addressed and subsequently resolved.

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Docket No. 50-213 B12248 Haddam Neck ISAP Topic No.1.56 Bolting Degradation October 1986

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Haddam Neck ISAP Topic No.1.56' Bolting Degradation (USI A-12)

I. Introduction V

A lack -of adequate material toughness which may be caused by the combination of low operating temperature, the presence of flaws in the material, and the effects of corrosion has raised concerns about potentist bolting degradation.

II. . Review Criteria

' NUREG-0577, Rev. 1 -

" Potential for Low Fracture Toughness and

-Lamellar Tearing:in PWR Steam Generator and Reactor Coolant Pump Supports" III. Related Topics / Interfaces ISAP Topic No.1.50 " Fracture Toughness of Supports" IV. Evaluation A plant-specific assessment of the Haddam Neck Plant was performed in accordance with the recommendations outlined in NUREG-0577, Rev.1.

No particular concerns were identified' based on this review. . Nonetheless,

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at the Haddam Neck Plant there is an ongoing program to monitor the degree of carbon steel bolting degradation with recommendations ~ to replace any bolts which are degrading, resulting from this program.

V. Conclusions Based on the above, CYAPCO considers this issue adequately addressed.

Resource allocations will be determined in the integrated assessment.