ML20115G507

Application for Amend to License NPF-38,revising TS 3.9.8.1, Shutdown Cooling & Coolant Circulation High Water Level & TS 3.9.8.2, Shutdown Coolant Circulation Low Water Level

ML20115G507
Person / Time
Site:	Waterford
Issue date:	07/18/1996
From:	Sellman M ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20115G510	List: ML20115G507 ML20115G520
References
W3F1-96-0096, W3F1-96-96, NUDOCS 9607190181
Download: ML20115G507 (9)

Text

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Enterg Operations,Inc.

-- Killona LA 70006-0751 Tel 504 739 6660 e Mike Sellman

', , c Pres dent Operations W3F1-96-0096 A4.05 i PR July 18,1996 U.S. Nuclear Regulatory Cornmission Attn: Document Control Desk l

Washington, D.C. 20555 l

Subject:

Waterford 3 SES i Docket No. 50-382 i License No. NPF-38 l Technical Specification Change Request NPF-38-177 I Gentlemen: 1 Entergy, Waterford 3, hereby submits a Technical Specification Change Request for .

revising Technical Specification 3.9.8.1 " Shutdown Cooling and Coolant Circulation High Water Level," and Technical Specification 3.9.8.2 " Shutdown Coolant Circulation Low Water Level." )1 This Technical Specification Change Request will change the water level at which  !

the Shutdown Cooling System is required to be operable and in operation based on l twenty three 23 feet above or below the reactor vessel flange to twenty three (23) {

feet above or below the top of the seated fuel assemblies. The safety analysis, the l existing Technical Specifications, and the proposed Technical Specifications are  ;

provided in the attachment to this letter. The proposed NRC Rule and Regulatory Guide for shutdown operations have been reviewed, and this Technical Specification Change Request has been found to be consistent with the proposed rule and regulatory guide. Further, other ABB Combustion Engineering (CE) plants j have existing Technical Specifications wherein the operability and operation of the '

Shutdown Cooling System is based upon twenty three (23) feet above the top of the seated fuel assemblies. These plants include: ANO Unit 2, Calvert Cliffs Unit 2, San Onofre Units 2 and 3, and Saint Lucie Unit 1.

t,SNJ72 9607190181 960718 PDR ADOCK 05000382 p PDR

l Technical Specification Change Request NPF-38-177 <

, W3F1-96-0096 f l Page 2 July 18,1996 l

This Technical Specification Change Request is a Cost Beneficial Licensing Action  !

(CBLA), and the approval of this request will allow Waterford 3 to significantly shorten the Refuel Outage 8 Schedule and save Waterford 3 approximately 13.5

) million dollars over the life of the plant.

Please contact Mr. James Fisicaro at (504)739-6242 should you have any questions or comments regarding this request -

i Very truly yours, i

Ih.,/ ,, ..

l M.B. Sellman i i Vice President, Operations l

l Waterford 3 l MBS/RJM/tmm

Attachment:

Affidavit NPF-38-177 cc: L.J. Callan, NRC Region IV C.P. Patel, NRC-NRR R.B. McGehee N.S. Reynolds NRC Resident inspectors Office Administrator Radiation Protection Division '

l -(State of Louisiana) j l American Nuclear Insurers l

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i UNITED STATES OF AMERICA

NUCLEAR REGULATORY COMMISSION l l

l . In the matter of

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j Entergy Operations, Incorporated ) Docket No. 50-382 '

!- Waterford 3 Steam Electric Station )

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AFFIDAVIT l

l M.B. Sellman, being duly sworn, hereby deposes and says that he is Vice President  !

i. Operations - Waterford 3 of Entergy Operations, Incorporated; that he is duly

! authorized to sign and file with the Nuclear Regulatory Commission the attached Technical Specification Change Request NPF-38-177; that he is familiar with the

! content thereof; and that the matters set forth therein are true and correct to the best of his knowledge, information and belief.

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M.B. Sellman l Vice President Operations - Waterford 3  !

j STATE OF LOUISIANA )

) ss PARISH OF ST, CHARLES )

Subscribed and sworn to before me, a Notary Public in and for the Parish and State above named this l 8" day of Ju t 1 .1996. i l

4 em b. a Notary Public i My Commission expires (~ 'W '- ' M .

" DESCRIPTION AND SAFETY ANALYSIS OF PROPOSED CHANGE NPF-38-177 This Technical Specification amendment request is a request to revise Technical Specification 3.9.8.1 " Shutdown Cooling and Coolant Circulation High Water Level,"

and Technical Specification 3.9.8.2, " Shutdown Cooling and Collant Circulation Low Water Level," to change the minimum water level above the irradiated fuel assemblies in the reactor cavity at which the Shutdown Cooling System (SDC) is required to be maintained operable or be in operation.

Existing Technical Soecifications See Attachment A Prooosed Technical Soecifications See Attachment B 4

Descriotion The function of the SDC system is to provide core cooling while the reactor is shutdown, by removing the decay heat being generated in the core. The SDC system is comprised of two SDC heat exchangers, two Low Pressure Safety injection (LPSI) pumps and their associated piping and valves. The SDC heat exchangers are cooled by Component Cooling Water (CCW) system. The SDC system is used to keep the reactor vessel temperature at or below 140*F, once the vessel is cooled to the SDC entry temperature of 350*F.

Currently, Technical Specification 3.9.8.1 requires that in mode 6 at least one train of SDC shall be operable and in operation when water level in the reactor cavity is equal to or greater than 23 feet above the reactor vessel flange.

Technical Specification 3.9.8.2 requires that in mode 6 with water level less than 23 feet above the reactor vessel flange, two independent trains of SDC shall be operable and at least one SDC train shall be in operation.

The proposed Technical Specification amendment would change the minimum water ,

level, from 23 feet above the reactor vessel flange to 23 feet above the irradiated fuel assemblies, in the reactor cavity at which the SDC System is required to be maintained operable or be in operation. Specifically, Technical Specification 3.9.8.1 would be changed to require one shutdown cooling train to be operable and in operation when the water level above the top of the irradiated fuel assemblies in the reactor vessel is

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greater than or equal to 23 feet. Technical Specification 3.9.8.2 would be changed to i requi~re.two independent shutdown cooling trains to be operable.and at least one shutdown cooling train to be in operation when the water level above the top of the irradiated fuel assemblies in the reactor vessel is less than 23 feet. The applicability modes, the action statements, and the surveillance requirements of Technical i Specifications 3.9.8.1 and 3.9.8.2 are not being changed. l The applicable safety issues or Technical Specification bases were identified, and each safety issue or Technical Specification bases is herein discussed:

One SDC Train in Operation. Sufficient Coolina Capacity Technical Specification bases 3/4.9.8 states that the requirement that at least one shutdown cooling train be in operation ensures that sufficient cooling capacity is available to remove decay heat and maintain the water in the reactor pressure vessel below 140 F as required during the refueling mode. The Technical Specifications will still require that one shutdown cooling train be in operation, and therefore, this Technical Specification bases is unaffected.

One SDC Train in Operation. Sufficient Coolant Circulation .

J Technical Specification bases 3/4.9.8 states that the requirement that at least one shutdown cooling train be in operation ensures that sufficient coolant circulation is maintained through the reactor core to minimize the effects of a boron dilution incident and prevent boron stratification. The Technical Specifications will still require that one shutdown cooling train be in operation, and therefore, this Technical Specification bases is unaffected.

Ruoture Of An irradiated Fuel Assemb!v Technical Specification 3.9.10.1 states that at least 23 feet of water shall be maintained over the top of the reactor pressure vessel flange during movement of fuel assemblies.

Technical Specification bases 3/4.9.10 states that the restrictions on minimum reactor vessel water level ensure that sufficient water depth is available to remove 99% of the assumed 10% iodine gap activity released from the rupture of an irradiated fuel assembly. Also, the fuel handling accident analysis is a function of the water depth over the irradiated fuel assemblies in the reactor core. Technical Specification 3.9.10.1 will not be changed and will be complied with, and therefore, the assumptions related to iodine removal and the fuel handling accident will be preserved.

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Reactor Core Coolina iechnical Specification bases 3/4.9.8 states that 23 feet above the reactor vessel 1 flange ensures that adequate time is available to initiate emergency procedures to cool the core.

An analysis was performed to demonstrate there is sufficient water inventory in the I reactor cavity with 23 feet of water above the top of the irradiated fuel assemblies to 1 allow the operators to recover from the loss of SDC prior to boiling in the reactor i vessel. The analysis was performed in two steps:

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1) The first step was to determine the time to boiling in the event of a loss of shutdown cooling.

2) The second step was to establish a time at which the core would be uncovered due to boil-off, following a loss of shutdown cooling.

The initial pool temperature was assumed to be 140*F. The nozzle dams are assumed  ;

to be installed. The cooling of the vessel using natural circulation is no longer possible i with the nozzle dams installed. Also, the available inventory for heat-up is less with the i nozzle dams installed since the water in the steam generator could not be credited.

The volume of water in the cold and hot legs, lower plenum, core bypass, and the downcomer was conservatively ignored for the time to boil and the core uncovery calculations. The available pool volume contributing to heat-up was limited to the upper plenum, the active and inactive core regions, and the cavity pool inventory i directly above and in the immediate vicinity of the reactor vessel flange. The volume above the active fuel and the upper plenum in addition to the cavity pool inventory  ;

above the twenty (20) foot MSL, volume above vessel flange, were credited for the time to core uncovery calculation. ,

i The time to boil was calculated based on a standard heatup calculation using the following relationship:

dT/dt = Q/pVc, The 1979 ANS best estimate decay heat curve was used for the decay heat, Q, in the core.

The time to core uncovery was calculated by determining the mass (m) needed to uncover the core, m = pV, and dividing the mass (m) by the rate of mass dissipated due to boiling, dm/dt = Q/hg The time to' core uncovery includes the time first needed to reach boiling.  !

The time to boil was determined to be 1.00 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />, and the time to core uncovery was determined to be 27.74 hours8.564815e-4 days <br />0.0206 hours <br />1.223545e-4 weeks <br />2.8157e-5 months <br />. Both results are based on twenty three (23) feet of water above the top of the irradiated fuel, approximately 10 feet above the reactor flange, and the decay heat at four days after shutdown. j 1

_C_ontainment Closure P.e ability to establish containment closure is important as a defense in depth aeasure. The analysis of water inventory establishes that the operators would have significant time withi;i which to close the containment prior to the initiation of boiling in i

the reactor vessel. Waterford 3 has also demonstrated the ability to quickly close the equipmeni hatch during mid loop operations, approximately 15 minutes, and has implemented measures to ensure the expeditious closure of the equipment hatet.

These measures include, for example, review of procedures among cognizant 4 personnel, equipment hatch area walk downs, and staging of equipment and tools.

Although personnel are not specifically designated to implement these measures when the water level is twenty three feet above the top of the fuel assemblier. the equipment and tools necessary for the closure of the equipment hatch are stageo :.cl personr'el are .available to cica the equipment hatch and establish containment closure as expeditiously as possible. Waterford 3 will implement the appropriate measures for the

[ condition with water level twenty three feet above the fuel assemblies to ensure

, containment closure can be established prior to the initiation of boiling. Therefore, the ability to establish containment cicsure will be maintained.

Benefit j This Technical Specification Change Request is a Cost Beneficial Licensing Action j (CBLA). This change will allow Waterford 3 personnel to start work on the shutdown 1

cooling system earlier in the refueling outage, and save on average, about 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> of critical path time per refueling outage. The estimated savings of this Technical Specification Change Requost is about 13.5 million dollars over the life of the plant.

Safety Analysis The proposed change described above shall be deemed to involve a significant .

hazards consideration if there is a positive finding in any of the following areas:

1. Will operation of the facility in accordance with this proposed change invoise a significant increase in the probability or consequence of any accident?

Response. No l

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The operation of the facility in accordance with this change does_not involve an incre'ase in the probability of any accident.

Changing the water level at which the SDC is required to be maintained operable or be in operation will not inwease the probability or consequences of an at~.Jent. The design, operation, or cc.1 figuration of the SDC system will not be changed.

1 At least one shutdown cooling train will be in operation to ensure that sufficient cooling capacity is available to remove decay heat and maintain the water in the reactor

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pressure vessel below 140 F as required during the refueling mode.

At least one shutdown cooling train will be in operation to ensure that sufficient coolant circulation is maintained through the reactor core to minimize the effects of a boron dilution incident and prevent boron stratification. Technical Specification 3.9.10.1 will be complied with, and therefore, the assumptions related to iodine removal and the fuel j handling accident will be preserved.

j Sufficient time, approximately 1.00 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />, will be a.vailable to the operators to initiate

compensatory measures to preclude the initiamn of core boiling in the unlikely event i that SDC should be loss. l l

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2. Will operation of the facility in accordance with this proposed change create the 1 possibility of a new or different kind of accident from any accident previously evaluated?

Response: No 1

The operation of the facility in accordance with this proposed change will not create the '

possibility of a new or different kind of accident from any accident previously evaluated.

The proposed change will not affect the design, configuration, or operation of the SDC system, and therefore there are no new modes cf failure introduced.

3. Will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety?

Response: No Operation of the facility in accordance with this proposed change will not involve a significant reduction in a margin of safety.

The calculation of the time to the initiation of boiling based on 23 feet above the top of the irradiated fuel, at four days after shutdown, demonstrates there is a significant time available, approximately 1.00 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />, to the operators within which to take

compensatory measures to preclude the initiation of boiling. The calculation shows that based on 23 feet of water above the reactor flange there is 2.04 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> to the  :

initiation of boiling. Although, there is a reduction in the time to the initiation of boiling, compensatory measures could be taken within a few minutes to restore SDC, and thus, there is still a significant margin available to the operators within which to preclude the initiation of boiling. Thus, the margin of safety is not significantly reduced.

The time to core uncovery was determined to be 27.74 hours8.564815e-4 days <br />0.0206 hours <br />1.223545e-4 weeks <br />2.8157e-5 months <br /> based on four days after shutdown and water level twenty three (23) feet above the irradiated fuel assemblies.

Safety and SioNtat Hazards Determination Based on the above safety analysis, it is concluded that: (1) the proposed change does not constitute a significant hazards consideration as defined by 10CFR50.92; and (2) there is a reasonable assurance that the health and safety of the public will not be endangered by the proposed change; and (3) this action will not result in a condition which significantly alters the impact of the station on the environment as described in the NRC final environmental statement.

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