ML081640317

Transmittal of Supplemental Information Request

ML081640317
Person / Time
Site:	Nine Mile Point
Issue date:	06/05/2008
From:	Polson K Constellation Energy Group
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC MD6942
Download: ML081640317 (7)

Text

Keith J. Poison P.O. Box 63 Vice President-Nine Mile Point Lycoming, New York 13093 315.349.5200 315.349.1321 Fax 0Constellation Energy-Nine Mile Point Nuclear Station June 5, 2008 U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION:

Document Control Desk

SUBJECT:

Nine Mile Point Nuclear Station Unit No. 1; Docket No. 50-220 License Amendment Request Pursuant to 10 CFR 50.90: Revisions to Operability Requirements for Reactor Coolant System Isolation Valves - Response to NRC Request for Additional Information (TAC No. MD6942)

REFERENCES:

(a) Letter from K. J. Poison (NMPNS) to Document Control Desk (NRC), dated September 27, 2007, License Amendment Request Pursuant to 10 CFR 50.90:

Revisions to Operability Requirements for Reactor Coolant System Isolation Valves - Technical Specification Sections 3.2.7 and 3.6.2 (b) Letter from R. V. Guzman (NRC) to K. J. Poison (NMPNS), dated April 8, 2008, Request for Additional Information Regarding Nine Mile Point Nuclear Station, Unit No. 1, Revised Operability Requirements for Reactor Coolant System Isolation Valves (TAC No. MD6942)

Nine Mile Point Nuclear Station, LLC (NMPNS) hereby transmits supplemental information requested by the NRC in support of a previously submitted request for amendment to Nine Mile Point Unit 1 (NMPl)

Renewed Operating License DPR-63. The initial request, dated September 27, 2007 (Reference a) proposed to revise the operability requirements contained in Technical Specification (TS) Section 3.2.7, "Reactor Coolant System Isolation Valves," and associated requirements contained in TS Section 3.6.2, "Protective Instrumentation." The supplemental information, provided in Attachment 1 to this letter, responds to the request for additional information (RAI) documented in the NRC's letter dated April 8, 2008 (Reference b).

This supplemental information does not affect the No Significant Hazards Determination analysis provided by NMPNS in Reference (a). Pursuant to 10 CFR 50.91(b)(1), NMPNS has provided a copy of this supplemental information to the appropriate state representative. This letter contains no new regulatory commitments.

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Document Control Desk June 5, 2008 Page 2 Should you have any questions regarding the information in this submittal, please contact T. F. Syrell, Licensing Director, at (315) 349-5219.

Very truly yours, STATE OF NEW YORK COUNTY OF OSWEGO

TO WIT:

I, Keith J. Poison, being duly sworn, state that I am Vice President Nine Mile Point, and that I am duly authorized to execute and file this supplemental information on behalf of Nine Mile Point Nuclear Station, LLC. To the best of my knowledge and belief, the statements contained in this document are true and correct. To the extent that these statements are not based on my personal knowledge, they are based upon information provided by other Nine Mile Point employees and/or consultants. Such information has been reviewed in accordance with company practice and I believe it to be reliable.

Subscribed and sworn before me, a Notary Public in and for the State of New York and County of

~,this 5'7$day of_9[tA"

, 2008.

WITNESS my Hand and Notarial Seal:

Notary Public SANDRA A. OSWALD Notary Public, State of New York No. 01OS6032276 Qualified in Oswego.Cquniy, Commission Expires.6L/,,O.0 My Commission Expires:

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Attachment:

1.

Nine Mile Point Unit 1 - Response to NRC Request for Additional Information Regarding Proposed Revisions to Technical Specification Sections 3.2.7 and 3.6.2 cc:

S. J. Collins, NRC R. V. Guzman, NRC Resident Inspector, NRC J. P. Spath, NYSERDA

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED REVISIONS TO TECHNICAL SPECIFICATION SECTIONS 3.2.7 AND 3.6.2 Nine Mile Point Nuclear Station, LLC June 5,2008

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED REVISIONS TO TECHNICAL SPECIFICATION SECTIONS 3.2.7 AND 3.6.2 By letter dated September 27, 2007, Nine Mile Point Nuclear Station, LLC (NMPNS) submitted a license amendment request to revise the operability requirements contained in Nine Mile Point Unit 1 (NMP1)

Technical Specification (TS) Section 3.2.7, "Reactor Coolant System Isolation Valves," and associated requirements contained in TS Section 3.6.2, "Protective Instrumentation." This attachment provides supplemental information in response to the request for additional information documented in the NRC's letter dated April 8, 2008. Each individual NRC question is repeated (in italics), followed by the NMPNS response.

Question 1 The LAR states (see Section 3, page 4 of 10) that the differences in the requirements of the TS Sections 3.2.7. a and 3.3.4. a have caused uncertainty in applying the requirements since the RCSIVs also perform a primary containment isolation function following a design basis loss of coolant accident. The LAR further states that Nine Mile Point Nuclear Station, LLC (NMPNS) has been applying the requirements of both TS sections to the RCSIVs. The proposed change would make it clear that the RCSIVs are required to be operable in both the power operating condition and the hot shutdown condition.

(a) Explain how the proposed requirements differ from the requirements as presently applied. For instance, is it correct that operability requirements as presently applied to RCSIVs cover hot shutdown conditions only when reactor coolant system temperature is greater than 215 degrees Fahrenheit (YF) and that no operability requirements have been applied when reactor coolant temperature is above 212YF but less than 215°F?

(b)

If correct, please confirm that the proposed requirements will also cover the period(s) when the reactor coolant temperature is above 212YF but less than or equal to 215°F.

Response

Part Current NMP1 TS Section 3.2.7.a requires that all reactor coolant system isolation valves (RCSIVs) on lines connected to the reactor coolant system be operable during power operating conditions whenever the reactor head is on. TS Definition 1.1 defines the power operating condition as: (1) reactor mode switch is in startup or run position; and (2) reactor is critical or criticality is possible due to control rod withdrawal.

Thus, the TS Section 3.2.7.a requirement is not dependent on any specific reactor coolant system temperature.

Current NMP1 TS Section 3.3.4.a (Primary Containment Isolation Valves) requires that all primary containment isolation valves on lines open to the free space of the primary containment be operable whenever the reactor coolant system temperature is greater than 215'F and primary containment is required. This requirement is dependent only on reactor coolant system temperature and not on any specific mode switch position.

Both of the above TS requirements are currently applied to RCSIVs since the RCSIVs would perform a primary containment isolation function following a design basis loss of coolant accident (LOCA).

However, because of the differing conditions of applicability in TS Sections 3.2.7.a and 3.3.4.a, there is a lack of clarity regarding the RCSIV operability requirements during plant shutdown evolutions, when I of 4

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED REVISIONS TO TECHNICAL SPECIFICATION SECTIONS 3.2.7 AND 3.6.2 both the reactor coolant system temperature and the mode switch position are changing. During a plant shutdown, if the mode switch is left in the startup position, the RCSIVs are required by TS Section 3.2.7.a to be operable (even if the reactor coolant system temperature falls below 215'F). Alternatively, if during a plant shutdown the mode switch is placed in the shutdown position prior to the reactor coolant system temperature being reduced to 215'F, operability of the RCSIVs is not required once the reactor coolant system temperature is < 215'F, since neither TS Section 3.2.7.a nor TS Section 3.3.4.a would then apply (i.e., mode switch is not in startup or run position, and reactor coolant temperature is < 215'F). Reactor mode switch position during plant shutdowns is dependent on the nature of the shutdown (controlled shutdown versus a plant scram) and the expected duration of the shutdown period.

Part (b)

The proposed change to TS Section 3.2.7.a described in the NMPNS letter dated September 27, 2007, would replace the phrase "During power operating conditions whenever the reactor head is on" with the phrase "Whenever fuel is in the reactor vessel and the reactor coolant temperature is greater than 212'F,"

thereby removing the dependence on reactor mode switch position. Thus, RCSIV operability will be required whenever reactor coolant system temperature is greater than 212'F with fuel in the reactor vessel, including periods when the reactor coolant system temperature is greater than 212'F and less than or equal to 215'F. This revised applicable operating condition is similar to operability requirements for other systems that are connected to the reactor coolant system (e.g., the core spray system, TS Section 3.1.4; and control rod drive pump coolant injection, TS Section 3.1.6).

Question 2 The NRC staff requests clarification regarding the proposed addition of operability requirements in TS Section 3.2.7.dfor the RCSIVs in the shutdown cooling (SDC) system. The LAR states that the proposed changes would require these valves to be operable whenever fuel is in the reactor vessel and the reactor coolant temperatures are less than or equal to 212YF. If an SDC system isolation valve becomes inoperable, proposed TS Section 3.2.7.e requires that, within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, at least one valve in each line having an inoperable valve is in the mode corresponding to the isolated conditions. However, if the SDC function is needed to provide core cooling, proposed TS Section 3.2. 7.f (1) allows the SDC line to remain unisolated provided action is immediately initiated to suspend operations having potential to drain the reactor vessel (OPDRVs). If suspending the OPDRVs would result in closing the SDC system isolation valves, an alternative action is proposed in TS Section 3.2. 7.f (2) to immediately initiate action to restore the valve(s) to operable status.

From the Updated Final Safety Analysis Report, Figure X-1, it appears that suspending OPDRVs will result in closing the SDC system isolation valves, and, therefore, would result in the alternative action of proposed TS Section 3.2. 7.f(2). The alternative action in TS Section 3.2. 7.f(2) is open ended, in that it is not time constrained to resolve the issue associated with the inoperable RCSIV While it is not the NRC staff's intent to imply that the issue would not be fixed, the proposed TS does offer an avenue to operate the SDC system while the problem remains unresolved. The SDC is a system that could be potentially called upon to operate more than once during a refueling outage.

(a) Explain what precautions would be taken, procedurally or otherwise, to preclude the potential for draining the reactor vessel during times when one of the RCSIV in the SDC system is inoperable and the plant is alternating between proposed TS action statements 3.2.7. e and 3.2. 7.f due to the 2 of 4

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED REVISIONS TO TECHNICAL SPECIFICATION SECTIONS 3.2.7 AND 3.6.2 need to intermittently operating the SDC system.

(b)

The LAR proposes to revise Table 3.6.2. b (low-low reactor water level function) to be consistent with the proposed RCSIV operability requirements described under TS Section 3.2.7. Please provide in your response, an explanation as requested in RAI 2(a) above, as it applies to the proposed TS Table 3.6.2. b.

Response

Part (a)

The additional requirements described in proposed new TS Sections 3.2.7.d, 3.2.7.e, and 3.2.7.f, pertaining to shutdown cooling (SDC) system RCSIVs, are modeled on NUREG-1433, Standard Technical Specifications - General Electric Plants, BWR/4, Revision 3.1 (Section 3.6.1.3, Condition H).

The associated TS Bases changes included in Attachment (3) of the NMPNS submittal dated September 27, 2007, are also modeled on NUREG-1433. During cold shutdown and refueling conditions (reactor coolant system temperature less than or equal to 212'F), maintaining decay heat removal capability is an essential function. The SDC system operates continuously to perform this reactor core fission product decay heat function, except when a system outage is necessary to perform system maintenance or surveillance testing activities. Control of reactor coolant system inventory is also essential to maintaining the overall decay heat removal function. Thus, ensuring that structures, systems, and components that perform both of these functions are available when needed is a fundamental element of maintaining shutdown safety.

In the event that a RCSIV in the SDC system becomes inoperable during shutdown conditions, the proposed new TS Sections 3.2.7.e and 3.2.7.f provide three options, as discussed below.

1. Close at least one valve in the line having the inoperable RCSIV, per TS Section 3.2.7.e.

Closing one of the RCSIVs in either the SDC suction or return line will terminate SDC system flow, thereby defeating the SDC system decay heat removal function. This is generally not desirable, since an extended loss of decay heat removal capability could result in boiling in the reactor, resulting in loss of water inventory and an unplanned operating mode change. Once isolated, re-opening of the inoperable valve would not be allowed until repairs were completed and the valve restored to operable status, after which TS Section 3.2.7.e could be exited.

2. Immediately initiate action to suspend operations with a potential for draining the reactor vessel (OPDRVs), per TS Section 3.2.7.f(1).

This specification allows the shutdown cooling line to remain unisolated provided action is immediately initiated to suspend OPDRVs. Suspending OPDRVs is intended to preserve reactor coolant system inventory. Consistent with NUREG-1433, the term "immediately" means that the action should be pursued without delay and in a controlled manner. This action would need to continue until OPDRVs are suspended. During shutdown. conditions, the SDC system becomes part of the reactor coolant system boundary; however, simply having the SDC system in service is not considered an OPDRV so long as SDC system integrity is maintained. System integrity is maintained provided the piping is intact and no maintenance is being performed that has the potential for draining the reactor vessel through the system. Maintenance activities having the potential to adversely affect 3 of 4

ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED REVISIONS TO TECHNICAL SPECIFICATION SECTIONS 3.2.7 AND 3.6.2 SDC system pressure boundary integrity or to drain the reactor vessel through the system would be assessed in accordance with the NMPNS shutdown safety procedure. As long as SDC system integrity is being maintained, system operation can continue until repair of the inoperable SDC system RCSIV is completed. With the valve returned to operable status, TS. Section 3.2.7.f(l) would be exited.

If SDC system integrity is not being maintained, then suspending OPDRVs would require closure of the SDC system RCSIVs. As for the first option above, this action would defeat the SDC system decay heat removal function, which is not desirable. Thus, a third option is provided.

3.

Immediately initiate action to restore the valve to operable status, per TS Section 3.2.7.f(2).

This alternative is provided for the case where suspending OPDRVs would result in closing the SDC system RCSIVs. It allows the SDC system to remain in service while actions are being taken to restore the valve. Consistent with NUREG-1433, the term "immediately" means that the action should be pursued without delay and in a controlled manner. This action would continue until the valve is restored to operable status, after which TS 3.2.7.f(2) would be exited. Due to the importance of maintaining the decay heat removal and reactor coolant system inventory control functions during shutdown conditions, the RCSIV repair would be expected to proceed in a timely manner.

The course of action chosen for any specific instance of an inoperable SDC system RCSIV would depend on the nature of the valve problem, the magnitude of the reactor core decay heat, the reactor coolant system inventory condition and availability, the reactor coolant system configuration, maintenance activities either ongoing or planned, and availability of alternate means for decay heat removal.

Part (b)

The same general philosophy outlined in the response to Part (a) of Question 2 is applicable to the proposed changes to TS Table 3.6.2b. These changes would require that the low-low reactor vessel water level instrumentation that initiates isolation of the SDC system be operable with the reactor mode switch in the Shutdown and Refuel positions. In the cold shutdown and refueling conditions, only one trip system (with two instrument channels) must be operable as long as SDC system integrity is maintained.

System integrity is maintained provided the piping is intact and no maintenance is being performed that has the potential for draining the reactor vessel through the system. If one low-low water level instrument channel in a required trip system becomes inoperable and cannot be restored or placed in the tripped condition within the allowed time, the associated SDC line should be isolated. However, if SDC system operation is needed for reactor core decay heat removal, isolating the SDC line is not desirable. The proposed addition of Note (j) to TS Table 3.6.2b allows the SDC line to remain unisolated and the system to remain in service provided action is immediately initiated to restore the channel to operable status. The alternative is to immediately initiate action to isolate the SDC system, which may require that alternate decay heat removal capabilities be provided. The term "immediately" means that the action should be pursued without delay and in a controlled manner. Either of these actions must continue until the channel is restored to operable status or the shutdown cooling system is.isolated. Due to the importance of maintaining the decay heat removal and reactor coolant system inventory control functions during shutdown conditions, the instrument channel repair would be expected to proceed in a timely manner.

Note that if the low-low reactor vessel water level instrumentation that automatically initiates isolation of the SDC system is inoperable, the capability still exists to manually close the SDC system RCSIVs.

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