B12204, Forwards Reviews of Isap Topic 1.14.1, Curbs Ramps Water Control Structures,Seals & Shields & Isap Topic 1.49, Steam Generator Tube Integrity

Forwards Reviews of Isap Topic 1.14.1, Curbs Ramps Water Control Structures,Seals & Shields & Isap Topic 1.49, Steam Generator Tube Integrity

ML20214V825
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	09/18/1986
From:	Opeka J, Sears C CONNECTICUT YANKEE ATOMIC POWER CO.
To:	Charemagne Grimes Office of Nuclear Reactor Regulation
References
B12204, NUDOCS 8610020423
Download: ML20214V825 (7)

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. o CONNECTICUT YANKEE ATOMIC POWER COMPANY B E R L I N, CO N N ECTIC U T P o BOX 270 HARTFORD CONNECTICUT 06141-0270 TELEPHONE 2n3-665-5000 September 18,1986 Docket No. 50-213 B12204 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 Power Company (CYAPCO) 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.1.14.1 " Curbs, Ramps, Water Control Structures, Seals

& Shields"

2) ISAP Topic No.1.49 " Steam Generator Tube Integrity" If you have any questions concerning the attached reviews, please contact us.

Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY dbD

3. F. Opeka' Senior Vice President 8610020423 860918 By: C. F. Sears h y,

PDR ADOCK 05000213 Vice President C l P PDR i

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Docket No. 50-213 B12204 i

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Haddam Neck ISAP Topic No.'1.14.1 Curbs, Ramps, Water Control Structures, Seals and Shields t

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Haddam Neck ISAP Topic No.1.14.1 Curbs, Ramps, Water Control Structures, 5eals and Shields I. Introduction This topic is the result of CYAPCO's efforts regarding the requirements of the Fire Protection Rule,10 CFR 50.48 and Appendix R to 10 CFR 50.

The proposed modifications in this subtopic are necessary to demonstrate compliance with Appendix R criteria. These include the installation of radiant energy shields between redundant cable runs in containment penetrations, the sealing of all openings in cabinets in the Control Room, and providing curbing in the intake service water structure and the Primary Auxiliary Building (PAB). These modifications were designed to either isolate volatile or combustible materials from various trains of safety-related equipment or to provide adequate fire barriers for certain fire zones.

II. Review Criteria

1. 10 CFR 50.48 2.~ 10 CFR 50, Appendix R

3. National Fire Protection Association Code III. Related Topics / Interfaces

1. ISAP Topic No.1.14 " Appendix R Modifications"

2. ISAP Topic No. l.14.2

" Install New 480 V L/C and Rearrange Equipment In Fire Area S-8"

3. ISAP Topic No. 1.14.3 " Appendix R Related Control Circuit Modifications"

4. ISAP Topic No.1.14.4 " Remote Shutdown Instrumentation Panel"

5. ISAP Topic No.1.14.5 " Fire Protection Improvement Area S-1"

6. ISAP Topic No.1.14.6 " Installation of Fire Damper to Separate Charging Pumps" IV. Evaluation To date, the curbs have been installed in the intake structure to separate the service water pumps, and in the PAB to separate the RHR pumps.'

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Also, ramps and seals for the openings between control room cabinets and the floor have been installed, along with radiant energy shields designed to separate redundant cable runs.

V. Conclusions The commitments for all Appendix R work under this topic have been completed. Hence, CYAPCO considers this ISAP topic closed.

VI. References

1. W. G. Counsil letter to D. G. Eisenhut "Haddam Neck Plant Fire Protection", dated March 1,1982.

2. .W. G. Counsil letter to D. G. Eisenhut " Fire Protection Appendix R Review - Haddam Neck Plant - Supplementary Information", dated July 16,1982.

3. W. G. Counsil letter to D. G. Eisenhut " Fire Protection Appendix R Review - Haddam Neck Plant", dated December 15,1982.

4. W. G. Counsil letter to D. G. Eisenhut "Haddam Neck Plant -Control Room Auxiliary Panels", dated April 22,1983.

5. W. . G. Counsil . letter to . J. A. Zwolinski "Haddam Neck Plant, Exemption from 10 CFR 50, Appendix R", dated February 14,1985.

6. 3. F. Opeka letter to H. L. Thompson - "Haddam Neck Fire Protection", dated September 16,1985.

Docket No. 50-213 B12204 ,

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Haddam Neck ISAP Topic No.1.49 Steam Generator Tube Integrity September 1986

Haddam Neck ISAP Topic No.1.49 Steam Generator Tube Integrity (USI A-3)

1. Introduction Steam generator tube ruptures (SGTR), both as initiating events and as consequential events (induced by other transient events) have been recognized as potential safety concerns in the operation of nuclear power plants. Staff concerns relative to steam generator tube degradation stem from the fact that the steam generator tubes are a part of the reactor coolant system (RCS) boundary and that tube ruptures allow primary coolant into the secondary system where its isolation from the environment is not fully ensured. The leakage of primary coolant into the secondary system has two potential safety implications which were considered. The first is the direct release of radioactive fission products to the environment; the second is the loss of primary coolant water which is needed to prevent core' damage. An extended, uncontrolled loss of coolant outside of containment could result-in the depletion of the initial RCS water inventory and ECCS water without the capability to recirculate the water.

II.- Review Criteria

1. NUREG-0844 - "NRC Integrated Program for the Resolution of Unresolved Safety Issues A-3, A-4, and A-5 Regarding Steam Generator Tube Integrity"

2. Unresolved Safety Issue A-3 " Steam Generator Tube Integrity"

3. NUREG-0933 "A Prioritization of Generic Safety Issues" III. Related Topic / Interfaces-

1. ISAP Topic No. 2.01 " Secondary Side Chemistry Monitoring"

2. ISAP Topic No. 2.03 " Atmospheric Steam Dump"

3. ISAP Topic No. 2.06 " Evaluation of RCS Loop Isolation Valves to Mitigate SGTR"

4. ISAP Topic No. 1.4 5 "151 Update to 1980 Code" IV. Evaluation As discussed in Reference 1, several projects at Haddam Neck are currently in various stages of implementation aimed at reducing the likelihood of SGTR's. These items are being evaluated as separate ISAP topics. Overall, significant reduction of public risk may be forthcoming as a result of these respective changes.

l During the 1986 refueling outage, CYAPCO, using an improved signal processor, identified 575 steam generator tube ends as having " undefined eddy current signals" in the roll expansion regions. Subsequent examination showed crack initiation at the center of these regions in 540 of these tube ends. The flaw depths ranged from 22% to 100% through-wall. These were presumed to be caused by primary water stress corrosion. The possibility

of flaws in the 35 remaining tubes has been ruled out. Further analysis of these undefined signals is an ongoing commitment.

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Additionally, the new emergency EOPs based on the Westinghouse Owners Group Emergency Response Guidelines provide specific direction in mitigating SGTRs. These new EOPs are presently in place at the Haddam Neck Plant.

V.- Conclusions Based on the above, analysis of the specific ISAP topics related to tube integrity will continue and further evaluation of these topics will be undertaken in the integrated assessment.

VI. Reference

1. 3. F. Opeka letter to H. L. Thompson, " Response to GL 85-02, Steam Generator Tube Integrity", dated June 25, 1985.

2. 3.F. Opeka letter to C.I. Grimes, "Haddam Neck Plant - Repair of Steam Generator Tubes in the Tubesheet Roll Region," dated July 24, 1986.

3. C. I. Grimes letter to 3. F. Opeka, " Tube Plugging Criteria Following Discovery of Undefined Signals During Steam Generator Eddy Current Inspection of Tubes in the Tubesheet Region," dated July 30,1986.

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