ML18005B016

Submits Suppl to 890222 Request for Amend to License NPF-63 Re RHR Min Flow Requirements During Refueling Operations. Tech Spec Change Request Revises Surveillance Requirement 4.9.8.2.2 to Impose Min Flow Requirement of 900 Gpm

ML18005B016
Person / Time
Site:	Harris
Issue date:	08/22/1989
From:	Cutter A CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18005B017	List: ML18005B016 ML18005B018
References
GL-88-17, NLS-89-222, NUDOCS 8908280308
Download: ML18005B016 (13)

Text

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ACCESSION NBR:8908280308 DOC.DATE: 89/08/22 NOTARIZED: YES FACIL:50-400 Shearon Harris Nuclear Power Plant, Unit 1, Carolina DOCKET t

AUTHOR AFFILIATION 05000400 AUTH. NAME

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CUTTER,A.B..

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RECIPIENT AFFILIATION Light Co.

Document Control Branch (Document Control Desk)

SUBJECT:

Submits suppl to 890222 request for amend to License NPF-63 rer RHR minimum flow requirements during refueling.

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CIPILL Carolina Power & Light Company P.O. Box tast ~ Ratetgh, N.C. 27602 SERIAL: NLS"89-222 AUG 22 1989 10CFR50.90 A. B CUTTER Vice President Nuclear Services Department United States Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO. 50-400/LICENSE NO. NPF-63 SUPPLEMENT TO REQUEST FOR LICENSE AMENDMENT REFUELING OPERATIONS LOW MATER LEVEL Gentlemen:

In accordance with the Code of. Federal Regulations, Title 10, Parts 50.90 and 2.101, Carolina Power & Light. Company (CPSL) hereby submits a'supplement to the February 22, 1989 license amendment request concerning Residual Heat Removal (RHR) minimum flow requirements during refueling operations. This Technical Specification change request revises Surveillance Requirement 4.9.8.2.2 to impose a minimum flow requirement of 900 gpm when the reactor

~ater level is below the reactor vessel flange. The existing 2500 gpm flow requirement is maintained when the water level is at or above the reactor vessel flange. A change to the associated Bases section is also included for your information.

The proposed amendment is consistent with Generic Letter 88-17, "Loss of Decay Heat Removal," dated October 17, 1988, which advises licensees to submit changes to those technical specifications that restrict or limit the safety benefit of the action identified by the generic letter.

Enclosure 1 provides a detailed description of the proposed changes and the basis for the changes.

Enclosure 2 details the basis for the Company's determination that the proposed changes do not involve a significant hazards consideration.

Enclosure 3 is an environmental evaluation which demonstrates that the proposed amendment meets the eligibility criteria for categorical exclusion set forth in 10CFR51.22(c)(9), therefore, pursuant to 10CFR51.22(b), no environmental impact statement or environmental assessment need to be prepared in connection with the issuance of the amendment.

Enclosure 4 provides the proposed Technical Specification pages.

Enclosure 5 provides a summary of the Westinghouse Evaluation which verified that a minimum RHR flow of 900 gpm during Mode 6 mid-loop operation is sufficient to ensure adequate mixing for a boron dilution event.

8908280308 8+08 PDR ADQCK 05000400 P

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<Document Control Desk NLS-89-222 / Page 2 Carolina Power & Light Company requests approval of the proposed amendment by October 'll, 1989 in order to support planning for the upcoming SHNPP refueling outage currently scheduled to begin in October 1989. Please refer any questions regarding this submittal to Mr. John Eads at (919) 546-4165.

Yours very tr A. B. Cutter ABC/JHE/crs (432CRS)

Enclosures:

1. Basis for Change Request

2. 10CFR50.92 Evaluation 3 ~ Environmental Evaluation Technical Specification Pages

5. Summary of Westinghouse Evaluation cce Mr. R. A. Becker Mr. Dayne H. Brown Mr. W. H. Bradford Mr. S. D. Ebneter A. B. Cutter, having been first duly sworn, did depose and say that the information contained herein is true and correct to the best of his information, knowledge and belief; and the sources of his information are officers, employees, contractors, and agents of Carolina Power 6 Light Company.

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ENCLOSURE 1 SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO. 50"400/LICENSE NO. NPF-63 SUPPLEMENT TO REQUEST FOR LICENSE AMENDMENT REFUELING OPERATIONS LOW WATER LEVEL BASIS FOR CHANGE RE UEST Pro osed Chan e The proposed change affects Specification 3.9.8.2, Refueling Operations Low Water Level. Currently, Surveillance Requirement 4.9.8.2 requires that at least one Residual Heat Removal (RHR) loop be verified in operation and circulating reactor coolant at a flow rate of greater than or equal to 2500 gpm at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> when the reactor is in Mode 6 with irradiated fuel in the vessel and the water level above the top of the reactor vessel flange is less than 23 feet. The proposed amendment revises Surveillance Requirement 4.9.8.2 to impose a minimum RHR flow requirement of 900 gpm whenever the water level is below the reactor vessel flange. The 2500 gpm flow requirement is maintained when the water level is at or above the reactor vessel flange. The associated Bases section has also been revised to reflect this change.

Basis The existing requirement of Specification 3/4.9.8.2 that at least one RHR loop be in operation ensures that: (1) sufficient cooling capacity is available to remove decay heat and maintain the water in the reactor vessel below 140 F as required in Mode 6, and (2) sufficient coolant circulation is maintained through the core to minimize the effect of a boron dilution incident and prevent boron stratification. The Mode 6 minimum flow limit of 2500 gpm was established to alleviate the potential for boron stratification. However, achieving 2500 gpm flow rate at the reduced water levels of mid-loop operation could cause cavitation and eventual damage of the RHR pumps. Boron stratification is only a concern with the large volumes of water present when the refueling cavity is filled. Sufficient mixing exists, even at low RHR flow rates, to preclude boron stratification when the water level is below the reactor vessel flange. For the boron dilution event, administrative controls to isolate potential sources of non"borated water from the reactor, established in Technical Specification 3/4.9.1, prevent a boron dilution event while in Mode 6. However, even if a boron dilution event is assumed to occur, an evaluation has been completed which demonstrates that an RHR flow rate of 900 gpm provides sufficient mixing of the RCS volume used in the Mode 6 boron dilution analysis and that the existing FSAR analysis remains valid. A summary of this evaluation is provided in Enclosure 5.

The proposed amendment splits, the existing surveillance requirement into two separate surveillances. The first, Surveillance Requirement 4.9.8.2.1, is applicable when-the RCS water level is at or above the reactor vessel flange and maintains the 2500 gpm minimum flow limit. The second, Surveillance El-1 (432CRS)

Requirement 4.9.8.2.2, is applicable when the RCS water level is below the reactor vessel flange and requires that one RHR loop be verified in operation and circulating reactor coolant at a flow rate greater than or equal to 900 gpm'at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

The proposed amendment is consistent with Generic Letter 88-17, "Loss of Decay Heat Removal," dated October 17, 1988, which advises licensees to submit changes to those technical specifications that restrict or limit the safety benefit of the action identified by the generic letter.

El-2 (432CRS)

ENCLOSURE 2 SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO. 50-400/LICENSE NO. NPF-63 SUPPLEMENT TO REQUEST FOR LICENSE AMENDMENT REFUELING OPERATIONS LOW WATER LEVEL 10CFR50.92 EVALUATION The Commission has provided standards in 10CFR50.92(c) for determining whether a significant hazards consideration exists. A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated, (2) create the possibility of a new or different kind of accident from any accident previously evaluated, or (3) involve a significant reduction in a margin of safety. Carolina Power & Light Company has reviewed this proposed license amendment request and determined that its adoption would not involve a significant hazards consideration. The bases for this determination are as follows'.

Pro osed Chan e The proposed change affects Specification 3.9.8.2, Refueling Operations Low Water Level. Currently, Surveillance Requirement 4.9.8.2 requires that at least one Residual Heat Removal (RHR) loop be verified in operation and circulating reactor coolant at a flow rate of greater than or equal to 2500 gpm at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> when the reactor is in Mode 6 with irradiated fuel in the vess'el and the water level above the top of the reactor vessel flange is less than 23 feet. The proposed amendment revises Surveillance Requirement 4.9.8.2 to impose a minimum RHR flow requirement of 900 gpm whenever the water level is below the reactor vessel flange. The existing 2500 gpm flow requirement is maintained when the water level is at or above the reactor vessel flange. The associated Bases section has also been revised to reflect this change.

Basis The change does not involve a significant hazards consideration for the following reasons.'.

The proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated. The existing requirement of Specification 3/4.9.8.2 that at least one RHR loop be in operation ensures that: (1) sufficient cooling capacity is available to remove decay heat and maintain the water in the reactor vessel below 140 F as required in Mode 6, and (2) sufficient coolant circulation is maintained through the core to minimize the effect of a boron dilution incident and prevent boron stratification. The Mode 6 minimum flow limit of 2500 gpm was established to alleviate the potential for boron stratification under refueling conditions. However, achieving 2500 gpm flow rate at the reduced water levels of mid-loop operation could cause cavitation and eventual damage of the RHR pumps. Boron E2-1 (432CRS)

stratification is only a concern with the large volumes of water present when the. refueling cavity is filled. Sufficient mixing exists, even at low RHR flow rates, to preclude boron stratification when the water level is below the reactor vessel flange. For the boron dilution event, administrative controls to isolate potential sources of non-borated water from the reactor, established in Technical Specification 3/4.9.1, prevent a boron dilution event while in Mode 6. However, even if a boron dilution event is assumed to occur, an evaluation has been completed which demonstrates that an RHR flow rate of 900 gpm provides sufficient mixing of the RCS volume used in the Mode 6 boron dilution analysis and that the existing FSAR analysis remains valid.

Since boron stratification is not a concern at reduced RCS water inventories and since the minimum RHR flow of 900 gpm is sufficient to ensure adequate mixing for a postulated boron dilution event, the proposed revision to reduce the minimum flow limit to 900 gpm when the RCS water level is below the reactor vessel flange does not significantly increase the probability or consequences of an accident previously evaluated.

2. The proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated. The proposed amendment splits the existing surveillance requirement into two separate surveiLLances. The first, Surveillance Requirement 4.9.8.2.1, is applicable when the RCS water Level is at or above the reactor vessel flange and maintains the 2500 gpm minimum flow limit. The second, Surveillance Requirement 4.9.8.2.2, is applicable when the RCS water level is below the reactor vessel flange and requires that one RHR loop be verified in operation and circulating reactor coolant at a flow rate greater than or equal to 900 gpm at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. As stated above, the proposed amendment does not involve any physical changes, additions, modifications, or deletions to existing equipment or systems.

Therefore, the proposed amendment cannot create the possibility of a new or different kind of accident.

3. Reducing the minimum RHR flow Limit from 2500 gpm to 900 gpm"when the RCS water level is below the reactor vessel flange does not involve a significant reduction in the margin of safety. As stated above, the Mode 6 minimum flow limit of 2500 gpm was established to alleviate the potential for boron stratification under refueling conditions. Boron stratification is only a concern with the large volumes of water present when the refueling cavity is filled. Sufficient mixing exists, even at low RHR flow rates, to preclude boron stratification when the water level is below the reactor vessel flange. For the boron dilution event, administrative controls to isolate potential sources of non-borated water from the reactor, established in Technical Specification 3/4.9.1, prevent a boron dilution event while in Mode 6. However, even if a boron dilution event is assumed to occur, an evaluation has been completed which demonstrates that an RHR flow rate of 900 gpm provides sufficient mixing of the RCS volume used in the Mode 6 boron dilution analysis and that the existing FSAR analysis remains valid. Since the boron stratification is not a concern at reduced RCS water inventories and since the minimum RHR flow of 900 gpm is sufficient to ensure adequate mixing for a postulated boron dilution event, the proposed amendment does not result in a significant reduction in the margin of safety.

E2-2 (432CRS)

ENCLOSURE 3 SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO. 50-400/LICENSE NO. NPF-63 SUPPLEMENT TO REQUEST FOR LICENSE AMENDMENT REFUELING OPERATIONS " LOW WATER LEVEL ENVIRONMENTAL CONSIDERATION 10CFR51.22(c)(9) provides criterion for and identification of licensing and regulatory actions eligible for categorical exclusion from performing an environmental assessment. A proposed amendment to an operating license for a facility requires no environmental assessment if operation of the facility in accordance with the proposed amendment would not: (1) involve a significant hazards consideration', (2) result in a significant change in the types or significant increase in the amounts of any effluents that may be released offsite; and (3) result in an increase in individual or cumulative occupational radiation exposure. Carolina Power 6 Light Company has reviewed this request and determined that the proposed amendment meets the eligibility criteria for categorical exclusion set forth in 10CFR51.22(c)(9). Pursuant to 10CFR51.22(b), no environmental impact statement or environmental assessment need to be prepared in connection with the issuance of the amendment. The basis for this determination follows:

Pro osed Chan e The proposed change affects Specification 3.9.8.2, Refueling Operations Low Water Level. Currently, Surveillance Requirement 4.9.8.2 requires that at least one Residual Heat Removal (RHR) loop be verified in operation and circulating reactor coolant at a flow rate of greater than or equal to 2500 gpm at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> when the reactor is in Mode 6 with irradiated fuel in the vessel and the water level above the top of the reactor vessel flange is less than 23 feet. The proposed amendment revises Surveillance Requirement 4.9.8.2 to impose a minimum RHR flow requirement of 900 gpm whenever the water Level is below the reactor vessel flange. The existing 2500 gpm flow requirement is maintained when the water level is at or above the reactor vessel flange. The associated'ases section has also been revised to reflect this change.

Basis The change meets the eligibility criteria for categorical exclusion set forth in 10CFR51.22(c)(9) for the following reasons:

1. As demonstrated in Enclosure 2, the proposed amendment does not involve a significant hazards consideration.

2. The proposed amendment does not result in a significant change in the types or significant increase in the amounts of any effluents that may be released offsite. The Mode 6 minimum flow limit of 2500 gpm was established to alleviate the potential for boron stratification under refueling conditions. Boron stratification is only a concern with the large volumes of water present when the refueling cavity is filled.

E3-1 (432CRS)

Sufficient mixing exists, even at low RHR flow rates, to preclude boron stratification when the water level is below the reactor vessel flange.

For the boron dilution event, administrative controls to isolate. potential souices of non-borated water from the reactor, established 'in Technical Specification 3/4.9.1, prevent a boron dilution event while in Mode 6.

However, even if a boron dilution event is assumed to occur, an evaluation has been completed which demonstrates that an RHR flow rate of 900 gpm provides suffici'ent mixing of the RCS volume used in the Mode 6 boron dilution analysis and that the existing FSAR analysis remains valid.

Therefore,'he proposed amendment does not result in significant change in the types or significant increase in the amounts of any effluents that may be released offsite.

3. The proposed amendment does not result in an increase in individual or cumulative occupational radiation exposure. The method by which the required surveillance performed-will not be affected, only the acceptance criteria. Therefore, there will be no change in radiation exposure as a result of the proposed amendment.

E3-2 (432CRS)

ENCLOSURE 4 SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO. 50-400/LICENSE NO. NPF-63 SUPPLEMENT TO REQUEST FOR LICENSE AMENDMENT REFUELING OPERATIONS LOW WATER LEVEL TECHNICAL SPECIFICATION PAGES E4-1 (432CRS)