ML20236X409

Rev 0 to Use of Nonborated Water in Canister Loading Decontamination Sys

ML20236X409
Person / Time
Site:	Three Mile Island
Issue date:	12/02/1987
From:	Smith N GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20236X403	List: ML20236X401 ML20236X409
References
4240-3257-87-01, 4240-3257-87-0169-R0, 4240-3257-87-1, 4240-3257-87-169-R, NUDOCS 8712090174
Download: ML20236X409 (4)

Text

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Nu2Isar SAFETY ANALYSIS sA a 4240-3257-87-0169 Rev. # 0 Page I '

4 of TITLE USE OF NON-B0 RATED UATER IN THE i

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SA 4240-3257-87-0169-

.USE OF NON-BORATED. WATER H IN THE CANISTER LOADING DECONTAMINATION SYSTEM 1.0 _ PURPOSE'AND SCOPE This evaluition addresses the modification to the Canister Loading Decontamination;(CLD). System to allow use of non-borated water for-

.can' ster decontamination prior to shjpment. The purpose of-this moc' .fication is, to provide' the' capability'to' stabilize the Fuel Transfer Ca al (FTC)/ Spent Fuel: Pool (SFP) baron concentration. Boron

-concentration in the fuel pool has been increasing due_to borated water additions and evaporation.

The Canister Handling and Preparation,for Shipment (CHAPS) Safety Evaluation Report (SER) requires that the CLD System utilize

' demineralized water that has been borated to a minimum baron concentration of 4350' ppm. In addition,-the Boron hazards Analysis (BHA) requires that non-borated or~1ess than 4350 ppm borated water sources be.

. excluded from use'in systems, such as the FTC/SFP, which could conynunicate with the Reactor. Coolant System (RCS).

'2.0' SYSTEM MODIFICATIONS The proposed modification utilizes tne Bora'.2d Water Batching Tank

n. (SPC-T 5) as a non-borat,ed, hot uter source for canister ' . .

decontamination. SPC-T-5 was originally insta;.lec as part of the Standby Reactor: Coolant Pressure Control System and.is presently used as a mixing tank to provide borated water for various plant uses. When used for.

canister decontamination, the SPC-T-5 drain line will be connected to the suction side of a positive displacement pump. The discharge of this positive displacement pump will be routed via hose to the CLD System and connected to the system et CLO-V0ll. To accomplish this connection, quick disconnects will be added to the line upstream of CLD-V0ll. In addition, this modification will isolate the CLD System from the Defueling Water Cleanup System (DWCS) by cutting and capping lines to ensure that the CLD System does not communicate with the DWCS.

'The C.LD System is contained.within areas that have controlled ventilation and area isolation capability. This limits the environmental impact of the system during normal system operations, snutdown, or postulated accident conditions.

3.0 BORON DILUTION Since the.CLD System could communicate with the RCS via the DWCS,'the approach identified ir the BHA for preventien of deboration will be required for operation of the CLD System using non-borated water. Thus, physical isolation will be provideo between the CLD and DWC Systems when using non-borated water. This physical isolation consists of cutting and Lcapping all lines associated with the CLD System th9t tie-in to DWCS, thereby eliminating the possibility of non-borated water from the CLD System being inadvertently introduced into the RCS. Additionally, the potential for inadvertent hose connections will be minimized by existing

administrative controls and physical'walkdown prior to system operation.

2.0 Rev. 0/0274P

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SA 4240-3257-87-0169 During canister decontamination using non-borated water, a localized deboration of the SFP will occur in the vicinity of the cask loading station. The only credible means of obtaining a critical mass of fuel in this location during canister decontamination would be the result of a canister drop while lifting a canister from the cask loading station into the Fuel Transfer Cask. The results of a canister drop during Fuel Transfer Cask loading is analyzed in the CHAPS SER, Section 6.1, " Heavy Load Handling." This analysis states that if the canister and grapple were to drop while lifting a csnister into the FTC, the canister would fall back into the loading station canister guides and no unacceptable consequences to the equipment would occur. Furthermore, the drop height when the canister is in the full up position in the FTC is less than the designed drop limits for the canister. Therefore, should a canister drop occur in this position, the canister will remain intact and fuel debris and poison material will remain in a stable configuration within the canister.

4.0 CRITICALITY CONTROL Subcriticality.is ensured by establishing the Technical Specification required boron concentration during the defueling process and ensuring that this is maintained by monitoring the boron concentration and  !

inventory levels and by isolating potential deboration pathways. The boron concentration and inventory level of the FTC/SFP will be monitored in accordance with approved procedures to ensure that Technical Specification limits for boron concentration and inventory level are satisfied. Additionally, subcriticality is also meintained by the canister engineered safeguards and their storage arrays.

5.0 10 CFR 50/>9 EVALUATION It is concluded, based on the evaluations presented in this safety analysis, that the proposed modification to the Canister Loading Decontamination System may be implemented without undue risk to the health and safety of the public.

10 CFR 50.59 permits the holder of an operating license to make changes to the facility or perform a test or experiment, provided the change, test, or experiment is determined not to be an unreviewed safety question and does not invclve a modification to the Plant Technical Specifications.

A proposed change involves an unreviewed safety question if:

a. The probability of occurrence or the consequences of an accident or malfunction of equipment important to safety previously evaluated in the safety analysis report may be increased; or

b. The possibility for an accident or malfunction of a different type than any evaluated previously in a safety analysis report may be created; or

c. The margin of safety, as defined in the basis for any Technical Specifications, is reduced.

3.0 Rev. 0/0274P !

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SA 4240-3257-87-0169 i The BHA identifies methods of isolating the RCS which provide a high degree of assurance that a dilution event will not occur. One of these methods is to provide physical isolation between the RCS and less than 4350 ppm borated water sources. To ensure compliance with the BHA, physical isolation will be provided between CLD and DWC Systems when non-borated water is utilized in the CLD System. Furthermore, the NRC Amendment of Order dated April 23, 1985, recognized that maintaining the required boron concentration in the RCS, FTC, and SFP minimizes the potential for boron dilution of any of these water volumes in the event that these water sources communicate due to a leak or valve misalignment. 4

- In addition, the consequences of a canister drop while raising the canister into the FTC during decontamination has been analyzed and determined to result in no unacceptable consequences. j Subcriticality is ensured by establishing the Technical Specification required baron concentration during the defueling process and ensuring that this concentration is maintained by monitoring the boron concentration and inventory levels'and by isolating potential deboration pathways. Additionally, subcriticality is also maintained by the canister engineered safeguards.  ;

Based on the above analysis, GPU Nuclear concludes that the proposed

! -change does not increase the probability of occurrence or the consequences of an accident or malfunction of a different type than any addressed in a previous NRC-approved safety evaluation.

I Technical Specification safety margins at TMI-2 are concerned with criticality control and prevention of further core damage due to overheating. As demonstrated by this safety analysis, Technical Specification safety margins will be maintained throughout the decontamination process. Thus, the proposed change does not reduce the j margin of safety.as defined in the basis for any Tecnnical Specifications.

! Based on the above analysis, GPU Nuclear concludes that the proposed modified configuration of the Canister Loading Decontamination System does not constitute an unreviewed safety question as defined by l 10 CFR 50.59.

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4.0 Rev. 0/0274P l

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