ML20097F074

Forwards Holtec Rept HI-92765, Licensing Rept for Capacity Expansion of LaSalle County Station Unit 1 to Address Planned Rerack of Facility Spent Fuel Pool

ML20097F074
Person / Time
Site:	LaSalle
Issue date:	06/05/1992
From:	Shields J COMMONWEALTH EDISON CO.
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
Shared Package
ML20097F077	List: ML20097F074 ML20097F099 ML20097F112
References
NUDOCS 9206150159
Download: ML20097F074 (8)

Text

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') 1400 Opus Piece Ccmmonw:alth Ediscn

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(y Downers Grove,litinoit 60515 June 5,1992 s.

Dr. Thomas E. Morley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attn: Document Control Desk

Subject:

La Salle Station Unit 1

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l' Application for Amendment to Facliity Operating License NPF-11 Attachment A. Technical Specifications Unit 1 Spent Fuel Pool Rerack NHQ.DncheLNoJ0:313___

in accordance with 10CFR50.90, Commonwealth Edison (CECO) proposes to amend Appendix A, Technical Specifications, of Facility Operating License NPF-11.

The proposed amendment requests changes to Technical Specification 5.0, " Design Features" to address the planned rerack of the Unit 1 spent fuel pool.

The current spent fuel racks have a capacity for storing 1080 fuel assemblies. The new storage racks have a capacity for storing 3982 assemblics, plus up to four defective fuel assemblies for a total of 3986 luei assemblies. The reracking of the s 3ent fuel pool is scheduled to beain in March 1993 and therefore, CECO requests b RC approval of this amendmentby February 1,1993.

This amendment request is subdivided as follows:

1.

Attachment A provides a description of the proposed changes to the Techn! cal Specifications, and a descri;Aion and evaluation of the modification upon which the Technical Specification changes are based.

2.

Attachment B is the document " Licensing Report for Capacity Expansion of the LaSaile County Station Unit 1".

3.

Attachment C includes the marked-up Technical Specification page with the requested channes indicated.

4.

Attachment C erscribes CECO's evaluation penormed in accordance with 10CFR50.94.,, which confirms that no significant hazards consideration is involved.

5.

Attachment E provides the Environmental Assessment.

This proposed amandment has been reviewed and approved by both CECO On-Site and Off-Site Review in accordance w;th Commonwealth Edison procedures.

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l Dr. T.E. Murley June 5,1992 Commonwealth Edison is notifying the State of I!!inois of this application for amendment by transmitting a copy of this letter and its attachments to the designated State Official.

To the best of my knowledge and belief, the statements contained above are true and correct. In some respects, these statements are not based on mv personal knowledge, but upon information furnished by other Commonwealth Edison and contrtet r employees. Such information has been reviewed in accordance with company oractice, and I believe it to be reliable.

Please direct any questions you may have concerning this amendment request to this office.

Respectiolly,

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Jo Ann M. Shields Nuclear Licensing Administrator Attachments:

A.

Description ar Evaluation of the Pioposed Changes B.

LaSalle Station Unit 1 Spent Fuel Pool Licensing Aeport C.

Marked-Up Technical Specification Pages D.

Evaluation of Significant Hazards Consideration E.

Environmental Assessment cc:

A.B. Davis, Regional Administrator - Rlli D. Hills, Senior Resident inspector - LSCS B.L. Siegel, Project Manager - NRR Office of Nuclear Facility Safety - lDNS Subscribed and Sworn

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bet re me this S_ day MARYELLEN D. L O t. '

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"# Attachment A Description and Evaluation of Proposed Chances to Appondix A, Technical 4

Specifications of Facility Operatin;) Lice ne NPF-11 Dncription of the ProposedlechnicalSpecification_Obanse There are two spent fust storage >ools (fuel pools) at LaSalle County Station. The existing Unit 1 fuel racks have 1080 uel storage cells. The Unit 2 fuel pool has high density fuel storage racks, which has a total capacity of 4073 fuel assemblies and 43 special storago cells. LaSalle Station proposes to rerack the Unit 1 spent fuel pool to increase the storage capacity to 3986 spent fuel storage locations and 43 special storage cells. The addition of the new Unit 1 high density racks will provide for continuted dual unit full-core discharge capability through the year 2013. The new racks are also designed to provide future flexability to allow the safe storage of different fuel designs and higher fuel enrichments than presently used at LaSalle.

As a result of the proposed new racks, section 5.6 of the Design Features section of the LaSalle Unit 1 Technical Specifications requires changes to the spent fuel center to-center distance and to the maximum storage capacity of the fuel pool. In addition, Specification 5.6.1.2, criticality for dry storage of the first core load of fuel, is being deleted as it no longer applies.

Descnptiprtolthe_NenBacks The new spent fuel storage racks are free-standing and self supporting. The principal construction material for ine racks is stainiess steel, except for the neutron absorber material, which is a boron carbide aluminum compound with the brand name Boral"1 Each rack consists of individual cells with a 6.05 inch (nominal inside square dimension. Each cell accommodates a single Boiling Water Reactor (B)NR) fuel assembly. The fuel assembly can be stored in the storage locations in channelled or unchannelled configuration. The design data is provided in Attachment P.

Specific information concerning the rack design and safety analysis is contained in Attachment B, and includes:

Module Layout and Reracking Operation

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Rack Fabrication and Applicable Codes Criticality Safety Analyses Thermal-hydraulic Considerations Structural / Seismic Considerations Accident Analysis and Miscellaneous Structural Evaluations Analysis of Spent Fuel Pool Structure Radiological Evaluation Boral Surveillance Program Environmental Cost / Benefit Evaluation ZNLD/1847/15 w...... _...

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Thes~e topics thoroughly cover the safety design requiremente and evaluation of the design.

There will be no fuel (new or spent) stored in the Unit i fuel pool during the time of the rerack work. All spent fuel will be moved to the Unit 2 fuel pool prior to the star 1 of work and will rems!n there for the duration of the work. Administrative procedures and controls are used to prevent movement of heavy objects over the Unit 2 spent fuel storage pool to pr3tect the stored fuel from potential damage. Additional Administrative procedures and controls provide direction for the removal of the old spent fuel racks and the installation of the new racks. The removal and installation work requirements provide for continued safe operation of both LaSalle Unit i and 2 during tha work.

Fivaluatiotto11beftoppged3hanges Attachment B. Licensing Report for Capacity Expansion of the LaSalle County Station

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Unit 1, (Licensing Repo,t), documents that the design and analyses performed satisfy all governing requirements of the applicable codes and standards, in particular.

USNRC "OT Position for Review and Acceptance of Spent Fuel Storage and Handling Applications."

Irzchnical SpecificalloILGhanges The design features for spent fuel storage and new fuel storage are contained in the Unit 1 Technical Specification section 5.6., Fuel Storage. Sections 5.6.1.b and 5.6.3 require changes as a result of the proposed modification to the Unit 1 fuel pool.

The current spent fuel storage racks maintain a design basis requirement of a kg less than or equal to 0.95 by specifying a nominal 7 inch conter-to-center distance,

between fuel assemblies placed in the storage racks. Tha proposed storage racks meet the same design requirement with a n-ominal 6.26 inch center-to center distance between fuel assemblies placed in the storage racks. The criticality safety analysis to support this change is provided in Attachment B of section 4.0. The design will maintain a suberitical array under all specified design conditions, including a fuel drop accident. Therefore, it is proposed that Technical Specification 5.6.1.b be amended to read as follows:

5.6.1 The spent fuel storage racks are designed and shall be maintained with:

b. A ncminal 6.26 inch center-to-center distance between fuel assemblies plJ in the storage racks.

The current spent fuel racks have a capacity for storing 1080 fuel assemblies. The nu sWape racks have a capacity for storing 3982 assemblies, plus up to four

' Gctive.uol assemblies for a total of 3986 fuel assemblies. Therefore, it is proposed that Technical Specification 5.6.3 be amended to read:

5.6.3 The spent fuel storage pool is designed and shall be maintained with a storage capacity limited to no more than 3986 fuel assemblies.

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In' addition, it is requested that Technical Specification 5.6.1.2 be deleted,10 it was applicable only at the time prior to initial core loading and thus no longer appines.

CIiticality_S.ately Analysis 1Licentilog.Bepo1LS.eclimL4 0 m

The design basis fuel for the storage racks is an 8x8 BWR f uel rod assembly with a bundle average enrichment of 3.5 wt% U-235 (uniform enrichment of 3.75% in the 138 inch enriched zone), with no credit taken for gadolinium burnable poison.

Criticality analyses are performed for both normal and abnormal (or acident) conditions, and include all significant manufacturing and calculational uncertainties.

The Criticality Safety Analysis presented concluded that the neutron multiplication factor of the Unit 1 racks will be less than the Technical Specification hmit of 0.95 with 95% probability and 95% confidence, with the racks fully loaded with fuel of the highest anticipated reactivity and the pool flooded with water at a temperature corresponding to the highest reactivity (4 *C).

Current and future reload fuel bundles will be verified to be bounded by the design basis criticality evaluation by use of the verification methodology provided in Section 4.6. The use of both an in-core K-infinity and an enrichment limit is a refinement of the methodology approved for the LaSalle Unit 2 high density fuel racks. The in core j

K-infinity limit is based upon a 4.60-8G2 bounding bundle design, which is less reactive than the LaSalle Unit 1 design basis bu: die.

TheImal-tlydIAayltclnalyses1LiceDsiig Bepo1Section10 l

. System design heat removal capabilities presented in the LaSalle UFSAR were used The Fuel Pool Cooling and Cleanup System and the B Residual Heat Removal as the basis for the analyses.

The analyses performed were:

Evaluation of pool decay heat and pool bulk temperature variation with time.

Determination of the maximum poollocal temperature at the instant the bulk temperature reaches its maximum value.

Evaluation of the maximum fuel cladding temperature which established that bulk nucleate boiling at any location resulting in two phase conditions around the fuel is not possible.

Evaluation of the time to-boil if all heat rejection paths from the pool are lost.

Determination of the effect of a blocked fuel cell opening on the local water temperature and maximum cladding temperature.

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The thermal hydraulle analyses demonstrate the compliance of the reracked

+v LaSalle Unit i spent fuel pool with the provisions of Section lli of the USNRO "OT Position Paper for Review and Acceptance of Spent Fuel Storage and Handling -

- Applications."

Situctutal/ Seismic Considerationsil.icensingBeportSectionA0 The new racks are free standing, not imchcred to the fuel pool slab or the pool walls, and are not interconnected.

The structural and seismic analyses of the high density spent fuel rack under the seismic loadings postulated for the plant iuei pool are presented as are the details of the method of analysis, modeling assumptions, numencal convergence studies, and parametric evaluations periormed to establish the required margins of safety.

The seismic analyses are performed per a three dimensional (3 D) whole pool multi-rack dynamic model and a single rack 3 D dynamic model, both using the DYNARACK

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computer code. The analyses demonstrate the structural adequacy of the high density spent fuel racks as Seismic Category I structures capa ale of withstanding a safe shutdown earthquake (SSE) with no resultant damage to stored fuel.

Aqcident Analysis arid MiscellaneousEiructural EvaluatiorisLLicensing Repo._rt Sention LQ Accident analyses and miscellaneous evaluations were performed to demonstrate regulatory compliance of the new spent fuel racks. The following limiting accidents

-and miscellaneous structural evaluations are considered:

Refueling accidents - drop of a fuel assembly from 30" above the rack to the top of the rack or through a cell to the baseplate.

Analyses of tool drops from the elevated worktable.

Uplift load of 1200 lbs. (UFSAR condition)

Local cell wall buckling.

Analysis of welded joints due to an isolated hot cell.

In all cases, the results of the analyses comply with the regulatory requirements.

Analy. sis _oLSpent.Euel Pool Structureilicensing BeporLSectioD10 The finite element analysis, performed to provide a structural assessment, demonstrated that the spent fuel pool for LaSalle Unit 1 can safely support the new loads associated with the installation of the new high density spent fuel racks. The stresses in the pool have been shown to be within the LaSalle UFSAR.

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I a-Bacilological Evaluation; LicensingBepgILSection 9,0 The radiological consequences of the following aspects of the spent fuel rack modification were evaluated:

Fuel handling accident over the spent fuel racks Gaseous releases due to the storage of the additional fuel Solid radwaste due to the storage of the additional fuel Personnel exposure as a result of the increase in the amount of stored fuel Anticipated radiation exposure during the reracking-B. oral prveillance Program: LicensingEepoILEechon10.0 in order to assure the neutron absorption characteristics of the Boral" panels, a Boral* surveillance program is presented. This program will be M :emented by administrative procedures. A coupon removal and testing progre ' ;11 be incorporated into the LaSalle surveillance program.

EnvlonmentaLGost/BenefiLElvaluationLLicensingRepoILSection1LQ An evaluation of the environmental cost / benefit of the LaSalle rerack modification determined that the modification and Technical Specification changes will have no environmental impact beyond that which has been predicted and described in the NRC's Final Environmental Statement related to the operation of LaSalle Station.

In conclusion, it is requested that this amendment be approved. The reracking of the fuel pool is scheduled to begin in March 1992 and therefore, CECO requests NRC approval of this amendment by February 1,1993.

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Attachment B LaSalle Station Spent Fuel Pool Modification Licensing Report for Proposed Changes to Facility Operating License NPF-11 i

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