B12194, Forwards Reviews of Isap Topics 1.18,1.26 & 1.42, Reactor Coolant Pump Seal Cooling Mods, Relief Valve & Safety Valve Testing & RCS Vents Tech Specs, Respectively

Forwards Reviews of Isap Topics 1.18,1.26 & 1.42, Reactor Coolant Pump Seal Cooling Mods, Relief Valve & Safety Valve Testing & RCS Vents Tech Specs, Respectively

ML20215B124
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	09/19/1986
From:	Opeka J, Sears J CONNECTICUT YANKEE ATOMIC POWER CO.
To:	Charemagne Grimes Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737, RTR-REGGD-01.070, RTR-REGGD-1.070, TASK-2.B.1, TASK-2.D.1, TASK-2.K.3.25, TASK-TM B12194, NUDOCS 8610060372
Download: ML20215B124 (10)

Text

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CONNECTICUT YANKEE ATOMIC POWER COMPANY BERLIN, CONNECTICUT P o Box 270 HARTFORD, CONNECTICU f 06141-0270 TELEPHONE 203-ess e September 19,1986 Docket No. 50-213 B12194 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

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 1 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

1) ISAP Topic No.1.18 "RCP Seal Cooling Modifications" i

2) ISAP Topic No.1.26 "RV and SV Testing" l

3) ISAP Topic No.1.42 "RCS Vents TS" j 1

If you have any questions concerning the attached reviews, please contact us.  !

Very truly yours, 1

CONNECTICUT YANKEE ATOMIC POWER COMPANY l 1

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3. F. Opeka Senior Vice President 8610060372 DR 860919 ADOCK 05000213 QO\

PDR By: C. F. Sears g g Vice President

i e B Docket No. 50-213 B12194 Haddam Neck ISAP Topic No.1.18 RCP Seal Cooling Modifications j

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September 1986 I

Haddam Neck ISAP Topic No.1.18 RCP Seal Cooling Modifications I. Introduction The reactor coolant pump (RCP) seals at Haddam Neck are cooled in two l ways: (1) the component cooling water (CCW) system provides cooling to the RCP thermal barrier coolers and (2) the charging pumps provide injection flow to the seals. Either of these methods provides adequate seal cooling following RCP trip. Lack of cooling for the RCP seals, even with RCP trip, may eventually result in seal leakage and subsequent loss of reactor coolant system (RCS) inventory.

After a loss of offsite power (LOOP), both the CCW pumps and the charging pumps are automatically tripped and must be restarted by the operator. Although the RCPs also trip on a LOOP, the RCP seals still require cooling. If the operator fails to restart the charging pumps and/or the CCW pumps, the seals may fail resulting in a small loss of coolant accident (LOCA).

This topic is a result of NUREG-0737 Item II.K.3.25 which discusses in detail reactor coolant pump seal integrity following loss of offsite power.

(Reference 1).

II. Review Criteria NUREG-0737 II.K.3.25 " Loss of AC Power on Reactor Coolant Pump l Scals" III. Related Topics / Interfaces ISAP Topic No.1.28 "RCP Trip" IV. Evaluation In order to eliminate the reliance on operator action to provide RCP cooling-af ter a LOOP, the proposed project calls for automatic restoration of RCP seal cooling under these conditions. Two potential solutions are:

(1) auto-starting the centrifugal charging pumps or (2) auto-starting the CCW pumps af ter the diesels pick up the loads. Each of the proposed solutions are discussed below.

Automatic Restart of the Charging Pumps The diesel generators at Haddam Neck he se sufficient capacity to provide power for auto-starting the chargi.1g pumps after a LOOP, provided there is no coincident safety injection (SI) signal. If there is a concident safety injection signal, the diesel loading capabilities may be marginal. Hence, the charging pumps will not auto-start under these conditions. Cooling for the charging pumps lube oil is normally provided by CCW. However on a LOOP, the CCW pumps l

trip and fans designed to cool the lobe oil will auto-start. Auto-l starting the charging pumps will eliminate the need for operator

action to provide RCP seal cooling following a LOOP. However, for the accident sequence in which MCC-5 fails following a LOOP, auto-3 starting the charging pump will be ineffective for providing RCP seal cooling. The charging pumps are designed to trip on a loss of MCC-5 j because the switchover capability (both automatic and via control i room actuation) of the pump suction frorn the volume control tank to I the Refueling Water Storage Tank (RWST) is lost. In addition, the j main lube oil pumps and cooling fans for both charging pumps fail on '

loss of MCC-5. Without the cooling fans, the operator would still be required to restart CCW to provide cooling for the charging pumps (in l addition to manually aligning the charging pumps to the RWST and i loading the auxiliary tube oil pumps on the diesel). l

Recent modifications completed during the 1986 refueling outage provide tripping of the charging pumps on a loss of semi-vital AC power, which would result from loss of MCC-5. There is also a time delay which would allow the operator time to override a spurious trip signal.

' Automatic Restart of the CCW Pumps I Another option for automatically restoring cooling for the RCP seals i '

after a LOOP is automatically restarting the CCW pumps. The CCW pumps provide sufficient cooling for the RCP seals via the thermal barrier cooler. In addition, when the operator has to restore coolant j injection using the charging pumps, CCW should be available for charging pump lube oil cooling.

4 In order to make restoration of RCP seal cooling following a LOOP totally independent of operator action, two other modifications must also be made. Currently on a LOOP, the motor operated valves (MOV) in the service water (SW) supply lines to the CCW heat t

exchangers (MOVs 3 and 4) automatically close and must be reopened by the operator. Therefore, the automatic logic of these valves

. would have to be modified to automatically close only after a LOOP 1 coincident with an SI signal. Analysis is also required to ensure that sufficient service water would be available to cool the CCW heat exchangers.

The other modification which would be required is to have the CCW-l to-thermal barrier cooler flow control valve 608 (FCV-608) fail open

on a loss of MCC-5. CCW fails to provide RCP_ seal cooling because J FCV-608 fails closed on a loss of MCC-5. FCV-608 is not currently I required to close for containment isolation, therefore having this j valve fail open will not affect containment integrity.

I Automatically starting all three of the CCW pumps (assuming 2 of 3 j are required for success) and modifying MOVs 3 and 4 to remain open g following a LOOP would totally eliminate the need for. operator action to restore cooling to the RCP seals following a LOOP.

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V. Conclusions It is not expected that implementation of either of the above modifications would significantly reduce risk to the public. However, further evaluation will be provided in the integrated assessment.

VI. References

1. NUREG-0737, " Clarification of TMI Action Plan Requirements",

dated November,1980.

2. Letter from 3. F. Opeka to 3. A. Zwolinski of NRC, "Haddam Neck Plant, NUREG-0737 II.K.3.25, Loss of Alternating Current Power on Reactor Coolant Pump Seals," dated June 3,1985.

3. Letter from 3. A. Zwolinski to 3. F. Opeka, " Loss of Alternating Current Power on Reactor Coolant Pump Seals - TMI Action

! Item II.K.3.25," dated May 1,1985.  !

4. Letter from W. G. Counsil to D. M. Crutchfield of NRC, "Haddam Neck Plant, TMI Item II.K.3.25, Effect of Loss of AC Power on Pump ,

Seals," dated April 5,1983. l l

5. Letter from D. M. Crutchfield to W. G. Counsil, " Request for i Additional Information - TMI Item II.K.3.25, Power to Pump Seals -

Haddam Neck Plant", dated February 1,1983.

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Docket No. 50-213 B12194 i

l Haddam Neck ISAP Topic No.1.26 Relief Valve and Safety Valve Testing i

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Haddam Neck ISAP Topic No.1.26 Relief Valve and Safety Valve Testing I. Introduction General Design Criteria 14,15 and 30 of Appendix A to 10CFR50 require that the reactor coolant pressure boundary be designed, fabricated and erected to the highest quality standards and be tested to ensure an extremely low probability of abnormal leakage, rapidly propagating failure and gross rupture. These criteria also require that the design conditions of the reactor coolant boundary not be exceeded during any condition of normal operation, including anticipated operational occurrences.

i Proper operation of reactor coolant system relief and safety valves is vital a for conformance to these design criteria. The inability of a sufficient number of these valves to open could lead to a violation of the integrity of the reactor coolant system pressure boundary. The failure of one or more of these valves to close results in a direct violation of the reactor coolant system pressure boundary integrity.

Testing of these reactor coolant system relief and safety valves for design basis transients and accidents was required to demonstrate proper valve qualification.

II. Review Criteria

1. 10CFR50 Appendix A

2. Regulatory Guide 1.70, Revision 2

3. NUREG-0737 Item II.D.1, " Performance Testing of PWR Relief and Safety Valves" III. Related Topics / Interfaces  ;

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None .,

IV. Evaluation I The reactor coolant system power operated relief valves (PORVs) and safety valves are connected to the pressurizer steam space at the Haddam Neck Plant.

Transients and accidents that result in increasing reactor coolant system temperatures can cause an expansion of the coolant volume in the reactor

, coolant system such that the pressurizer level increases, resulting in an increase in pressurizer pressure. As the system pressure increases, two-phase and solid-water flow can occur through the reactor coolant system relief and safety valves.

This project involves testing of the RCS relief and safety valves at the i Haddam Neck Plant. This has been completed, and CYAPCO has concluded  ;

that the valves tested accurately reflect favorable performance under a wide range of expected operating and accident conditions (see Reference 2).

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V. Conclusion Pending evaluation by the Staff, CYAPCO considers this ISAP topic closed.

VI. References

1. W. G. Counsil letter to D. G. Eisenhut, "Haddam Neck Plant - NUREG-0737 Item II.D.1, Performance Testing of PWR Relief and Safety Valves," dated December 15,1982.

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3. A. Zwolinski letter to W. G. Counsil, " Performance Testing of Relief and Safety Valves - NUREC-0737, Item II.D.1," dated October 29,1984.

3.

W. G. Counsil letter to 3. A. Zwolinski, " Response to Request for Additional Information on Performance Testing of Relief and Safety Valves," dated April 15,1985.

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Docket No. 50-213 B12194 Haddam Neck ISAP Topic No.1.42 RCS Vents Technical Specifications I <

September 1986

Haddam Neck ISAP Topic No.1.42 RCS Vents Technical Specifications

1. Introduction item II.B.1 of NUREG-0737 recommends reactor coolant system head and

. high point vents which are remotely operable from the control room in order to vent non-condensible gases that may build up in the Primary System during an accident scenario. It also recommends that Technical Specifications be added which delineate the operability and surveillance requirements as well as prescribed actions in the event of valve l inoperability.

II. Review Criteria

1. NUREG-0737, item II.B.1 " Reactor Coolant System Vents"

2. 10 CFR 50.44, " Standards for Combustible Gas Control System in I Light-water-cooled Power Reactors" l 111. Related Topics / Interfaces l

None IV. Evaluation This project involved installation of high point vents, development and submittal of applicable procedures to the NRC, and incorporation of the requirements for the vent system into the Haddam Ned Flaiit Technical Specifications.

To date, all phases of this project have been completed, with the exception of the technical specification change. Haddam Neck is in the process of converting to Standard Technical Specifications, which includes the RCS ,

vents Technical Specifications. Once this conversion is complete, the RCS l vents Technical Specifications will be implemented.

V. Conclusion Pending conversion to Standard Technical Specifications, Haddam Neck considers this ISAP topic closed.

VI. References I 1. W. G. Counsil letter to D. M. Crutchfield, "Haddam Neck Plant, TMI Action Plan Item II.B.1, Reactor Coolant System High Point Vents,"

dated September 22,1982.

2. D. M. Crutchfield letter to W. G. Coensit, "NUREG-0737, Item II.B.1, Reactor Coolant System Vents", dated September 6,1983.

3. W. G. Counsil letter to D. M. Crutchfield, "Haddam Neck Plant, TMI Action Plan item II.B.1, Reactor Coolant System High Point Vents,"

dated February 21,1984.

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