L-2004-063, Additional Information for Proposed Spent Fuel Pool Soluble Boron Credit Amendment

Additional Information for Proposed Spent Fuel Pool Soluble Boron Credit Amendment

ML040890422
Person / Time
Site:	Saint Lucie
Issue date:	03/25/2004
From:	Jefferson W Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-2004-063
Download: ML040890422 (13)

Text

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Florida Power & Light Company, 6501 S. Ocean Drive, Jensen Beach, FL 34957 March 25, 2004 FPL L-2004-063 10 CFR 50.90 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 RE:

St. Lucie Unit I Docket No. 50-335 Additional Information for Proposed Spent Fuel Pool Soluble Boron Credit Amendment By letter L-2002-221 dated November 25, 2002, Florida Power & Light (FPL) submitted a proposed license amendment (PLA) to revise the St. Lucie Unit 1 Technical Specifications (TS).

The proposed amendment eliminates the need to credit BoraflexTm neutron absorbing material for reactivity control in the spent fuel pool (SFP) and instead credits a combination of soluble boron and fuel position in the storage racks to maintain reactivity within the effective neutron multiplication factor (krff) limits of 10 CFR 50.68. FPL provided two responses for additional information by letters L-2003-125 dated May 14, 2003 and L-2003-245 dated September 29, 2003.

Discussions with the NRC staff revealed that further clarification was required in order to integrate this proposed license amendment with the cask pit rack proposed license amendments requested by letter L-2002-187, dated October 23, 2002. The original November 25, 2002, PLA limited the request for soluble boron and fuel position credit to the spent fuel pool storage racks.

FPL now proposes that the cask pit storage rack also be included in the soluble boron credit licensing bases. The attachment provides FPL's justification that the criticality analysis for soluble boron credit bounds the criticality analysis for the Unit I cask pit rack such that the proposed Unit I Technical Specification changes would also be applicable for the Unit I cask pit rack. The initial cask pit rack PLA also proposed removing the description of the Boral poison material from the Technical Specifications. However, the NRC staff requested that a description of the Boral poison material be included in the proposed St. Lucie Unit 1 spent fuel pool design features Technical Specification. The Technical Specification markups and word-processed Technical Specification changes for Technical Specification pages 5-5, 5-6, and 5-6a integrate the soluble boron credit and cask pit rack proposed license amendments. These changes are provided in the same attachment, and are replacements for the those pages included in letter L-2002-221.

The original determination of No Significant Hazards Consideration bounds the information provided in this letter. In accordance with 10 CFR 50.91(b)(1), a copy is being forwarded to the State Designee for the State of Florida.

an FPL Group company

St. Lucie Unit 1 Docket No. 50-335 Additional Information for Proposed Spent Fuel Pool Soluble Boron Credit Amendment L-2004-063 Page 2 of 3 Please contact us if there are any questions about this submittal.

Very truly yours, William Jefferson, Jr.

Vice President St. Lucie Plant WJ/KWF Attachment cc:

Mr. W. A. Passetti, Florida Department of Health

St. Lucie Unit 1 Docket No. 50-335 Additional Information for Proposed Spent Fuel Pool Soluble Boron Credit Amendment L-2004-063 Page 3 of 3 STATE OF FLORIDA COUNTY OF ST. LUCIE

)Ss.

William Jefferson, Jr. being first duly sworn, deposes and says:

That he is Vice President, St. Lucie Plant, of Florida Power and Light Company, the Licensee herein; That he has executed the foregoing document; that the statements made in this document are true and correct to the best of his knowledge, information and belief, and that he As autho to execute the document on behalf of said Licensee.

Williae frsonfr STATE OF FLORIDA COUNTY OF ST. LUCIE Subscribed and sworn to before me this 2&dayof lrVf-,2004.

ft' i',

Lesle 1 Whhwen WCOMMISSION#

DD02212 EXPIRES May 12 2005 BONDED THRU ROY FAN INSUUMN K

Name of Notary ic (Type or Print)

William Jefferson, Jr. is personally known to me.

Attachment to FPL letter L-2004-063 Page I of 10 ADDITIONAL INFORMATION FOR THE SPENT FUEL POOL SOLUBLE BORON CREDIT AMENDMENT ST. LUCIE PLANT, UNIT 1 DOCKET NO. 50-335

Attachment to FPL letter L-2004-063 Page2 of 10

References:

1. Attachments and Enclosures to FPL letter L-2002-221, November 25, 2002, Proposed License Amendment, Spent Fuel Pool Soluble Boron Credit

2. Attachments and Enclosures to FPL letter L-2002-187, October 23, 2002, Proposed License Amendment, Addition of Cask Pit Spent Fuel Storage Racks Based on discussions with the NRC staff, minor changes to the proposed Technical Specification text would enhance integration of the cask pit rack and the soluble boron credit license amendments. Additionally, the cask pit rack was analyzed for optimal moderation at a soluble boron concentration of 0 ppm, and therefore is bounded by the soluble boron credit criticality analysis. As discussed later, there is justification for also applying the soluble boron credit acceptance criteria from 10CFR 50.68(b)(4) to the cask pit rack design.

The following paragraphs present the proposed revised text of Technical Specification Section 5.6.1 Desie'n Features - Fuel Storage Criticalit, which will replace the proposed changes to Technical Specification Section 5.6.1 included in letter L-2002-221. This revised wording achieves a thorough integration of cask pit rack and soluble boron credit amendments. It preserves a description of essential aspects of the cask pit rack design features after implementation of the soluble boron credit amendment. The baseline for the revised text is the Technical Specification changes proposed by letters L-2002-221 (the proposed changes made to Technical Specification Section 5.6.3 by letter L-2002-187 are shown for completeness).

Proposed new Section 5.6.1 for the Soluble Boron Credit Amendment Considering the presence of a Cask Pit Rack (text only - revised or newly added text is underlined) 5.6.1.a The spentffuelpool and spentfitel storage racks shall be maintained with:

1. kef less than 1.0 whenfullyflooded with unborated water, which includes an allowancefor biases and uncertainties as described in Section 9.1 of the Updated Final Safety Analysis Report.

2. A nominal 10.12 inches center to center distance betveen fiel assemblies in Region 1 of the spent fiuel pool storage racks, a nominal 10.30 inches center to center distance between fitel assemblies in the Region I cask pit storage rack, and a nominal 8.86 inches center to center distance betveen fuel assemblies in Region 2 of the spent file pool storage racks.

3. A keff less than or equal to 0.95 when flooded with water containing 500 ppm boron, including an allowance for biases and uncertainties as described in Section 9.1 of the Updated Final Safety Analysis Report.

4. For storage of enrichedfiuel assemblies, requirements of Criteria 1 and 3 shall be met bypositioningfuel in the spentfuel storage racks consistent with the requirements of Specification 5.6.1.c.

Attachment to FPL letter L-2004-063 Page 3 of 10

5.

Vessel Flux Reduction Assemblies (VFRAs), as defined in Section 9.1 of the Updated Final Safety Analysis Report, may be placed in any allowable fiel storage location.

6. Fissile material, not contained in a fuel assembly lattice, shall be stored in accordance with the requirements of Criteria I and 3.

5.6..b The Region I cask pit storage rack shall contain neutron absorbing material Moral) between stored fiuel assemblies when installed in the spent fiuel pool.

5.6.1.c Loading of spent fuel storage racks shall be controlled as described below. Criteria 2 and 3 beled do not apply to the Region I cask pit storage rack.

1.

The maximum initial planar average U-235 enrichment of anyfuel assembly inserted in a spentfiuel storage rack shall be less than or equal to 4.5 weight percent.

2. Fuel placed in Region 1 ofthe spent fuel pool storage racks shall comply with the storage patterns and alignment restrictions of Figure 5.6-1 and the minimum burnup requirements of Table 5.6-1 and Table 5.6-2.

3. Fuel placed in Region 2 of the spent fiel pool storage racks shall comply withi the storage patterns or allowed special arrangements of Figure 5.6-2 and the minimum burnup requirements of Table 5.6-1 and Table 5.6-2. The allowed special arrangement forfresh fuel may be repeated, provided the applicable interface requirements specified by the safety analysis are met.

4. Anyffuel satisfying criteria 5.6.1.c.1 includinrgfresh fuel may be placed in the Region I cask pit storage rack 5.6. 1.d The newifuel storage racks are designedfor dry storage of unirradiatedfuel assemblies having a U-235 enrichment less than or equal to 4.5 weight percent, while maintaining a keff of less than or equal to 0.98 under the most reactive condition.

The only substantive differences betveen the text presented above and text presented as a part of letter L-2002-221 are: 1) the description of certain cask pit rack features contained in proposed Item 5.6.1.b, and 2) addition of the cask pit rack storage pitch dimension in Item 5.6.1.a.2 (taken from Reference 2). None of these underlined text changes modify any aspect of the I OCFR 50.92 No Significant Hazards Determination presented in letter L-2002-221.

Basis for Application of Soluble Boron Credit Acceptance Criteria to Cask Pit Rack As discussed in Reference 2, criticality analyses of the Unit I cask pit rack were performed considering only the 0 ppm soluble boron condition with a :0.95 acceptance criterion. Table 4.1.6.4 of this reference documents that the neutron multiplication factor is 0.9061, (i.e., much less than 1.0) when the cask pit rack is filled with fresh fuel of the limiting enrichment, considering the presence of pure water with optimal moderation characteristics and other

Attachment to FPL letter L-2004-063 Page 4of 10 conservative assumptions. In part, cask pit rack criticality analyses did not explicitly consider soluble boron because the specified storage cell pitch and the density of fixed neutron absorber material integral to the cask pit rack were sufficient to fully meet published criticality acceptance criteria with no credit for soluble boron. Further, cask pit rack analyses did not explicitly consider soluble boron because these criticality calculations were performed several months prior to developing the methodology used when crediting soluble boron. Criticality analysis calculations performed as part of the soluble boron credit amendment request defined the fuel pool boron concentration required to control kff during non-accident conditions. Results from the soluble boron calculations were not explicitly incorporated back into the cask pit rack analysis (e.g., through a revision) because of the obvious nature of the incremental effect.

Including soluble boron from the surrounding water in the cask pit rack criticality analysis will not increase the neutron multiplication factor of the cask pit rack, since boron represents neither a source of neutrons nor fissionable material. Recognizing the presence of soluble boron in the cask pit rack analysis would not accelerate or promote the deterioration of the rack's Boral absorber material or otherwise lessen its effectiveness. Since the presence of soluble boron will not increase the effective neutron multiplication factor of the cask pit fuel array, it is logical to conclude that the Reference 2 analysis result complies with both kcff limits proposed for TS 5.6..a.

Secondly, it is appropriate to apply consistent TS criticality criteria to the cask pit rack and other Unit 1 spent fuel storage racks because the cask storage and loading area constitutes an integral part of the Unit I spent fuel pool. No mechanism is available to isolate the Unit I cask pit from the remainder of the spent fuel pool. Further, no mechanism exists to reduce the soluble boron concentration in the cask pit without inducing an equivalent change to the soluble boron concentration in the remainder of the spent fuel pool. For these reasons, it was appropriate to perform the analysis of postulated boron dilution events (provided in Reference 1) considering water volumes in the cask pit area of the pool when computing dilution times and volumes.

Invoking the acceptance criteria for soluble boron credit in the pool cask pit area ensures a consistent design basis with respect to neutron multiplication across all areas of the fuel pool.

Attachment to FPL letter L-2004-063 Page 5of 10 DESIGNREEATURES CONTROL ELEMENT ASSEMBLIES 5.3.2 The reactor core shall contain 73 full length and no part length control element assemblies. The control element assemblies shall be designed and maintained in accordance with the original design provisions contained in Section 4.2.3.2 of the FSAR with allowance for normal degradation pursuant to the applicable Surveillance Requirements.

5.4 REACTOR COOLANT SYSTEM DESIGN PRESSURE AND TEMPERATURE 5.4.1 The reactor coolant system is designed and shall be maintained:

a.

In accordance with the code requirements specified in Section 5.2 of the FSAR with allowance for normal degradation pursuant to the applicable Surveillance Requirements,

b.

For a pressure of 2485 psig, and

c.

For a temperature of 6500F, except for the pressurizer which Is 7000F.

VOLUME 5.4.2 The total water and steam volume of the reactor coolant system is 11,100 + 180 cubic feet at a nominal T,,g of 5670F, when not accounting for steam generator tube plugging.

5.5 EMERGENCY CORE COOLING SYSTEMS 5.5.1 The emergency core cooling systems are designed and shall be maintained in accordance with the original design provisions contained in Section 6.3 of the FSAR with allowance for normal degradation pursuant to the applicable Surveillance Requirements.

5.6 FUEL STORAGE CRITICALITY I

5.6.1.a The spent fue torager aR dasigqed and shall be maintained with:

1.

klff less than fully flooded with unborated water, which Includes an allowance fo ncertainties as described in Section 9.1 of the Updated Final Safety Analysis eport.

bmAq on ST. LUCIE - UNIT I 5-5 Amendment No. 22, 2, 75, 94, 445, 46a-

Attachment to FPL letter L-2004-063 Page 6 of 1 ser~re Ji~ Si a Mce

.Ke5'or e

i CRITICALITY (Continuedi Ue

2.

A nominal 10.12 inches cent to assemblies in Region 1 of thcste 8.86 inches center to center dista in Region 2 of the(storage racks.

3. (A b..

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4.

=tjdaw niU veiwee l

eglon I of the spent fuel storage racks ar desed for d store f

whic U-235 enrichment less than or equal to 4.5 weight I, g n can be useightper fuel which has achieved sufficient b eu h that storage In eg 1

uired. The Iniial rnup requirement of Figure 5.6-1At1 lb m

o storage of fel assemblies atIS

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in Region 2. Freshly disch dged a llbes may be moved temporarily into Region 2 fd r purpose polnelowd/ e tion 5f or repaire provided tht the s u

tion Is maintaine n a rboard pattern (ie fe ssms n mpty locations alined diago Following h

stogcapciotlrepair actvitieso all such fuel assemblie 5.7.1 Thosem Region 2 and the requirements of Figure 5.6-1 s

e met C St h e new fuel storage racks are designed for dry storage of Qba Pat~ed fuel assemblies having a U-235 enrichment less than or equal to 4.5 weight percent while maintaining a k3.7 of less than or equal lo 0.98 under the most reactive condition.

DRAINAGE 5.6.2 The fuel pool Is designed and shall be maintained to prevent Inadvertent draining of the pool below elevation 56 feet.

CAPACITY t_*

C.

ck onyx 5.6.3 The spent fuel povindand shall be maintained with a storage capacity limited tnomrthn1706 fuel assembiliey 5.7 SEISMIC CLASSIFICATION

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5.7.1 Those structures, systems and components Identified as seismic ClassI in Section 3.2.1 of the FSAR shall be designed and maintained to the original design provisions contained in Section 3.7 of the FSAR with allowance for normal degradation pursuant to the applicable Surveillance Requirement./

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Attachment to FPL letter L-2004-063 Page 7 of 1 Insert A:

A kdfr less than or equal to 0.95 when flooded with water containing 500 ppm boron, including an allowance for biases and uncertainties as described in Section 9.1 of the Updated Final Safety Analysis Report.

Insert B:

For storage of enriched fuel assemblies, requirements of Criteria 1 and 3 shall be met by positioning fuel in the spent fuel storage racks consistent with the requirements of Specification 5.6.l.c.

5.

Vessel Flux Reduction Assemblies (VFRAs), as defined in Section 9.1 of the Updated Final Safety Analysis Report, may be placed in any allowable fuel storage location.

6.

Fissile material, not contained in a fuel assembly lattice, shall be stored in accordance with the requirements of Criteria I and 3.

Insert C:

The Region 1 cask pit storage rack shall contain neutron absorbing material (Boral) between stored fuel assemblies when installed in the spent fuel pool.

c. Loading of spent fuel storage racks shall be controlled as described below. Criteria 2 and 3 do not apply to the Region 1 cask pit storage rack.

1. The maximum initial planar average U-235 enrichment of any fuel assembly inserted in a spent fuel storage rack shall be less than or equal to 4.5 weight percent.

2. Fuel placed in Region 1 of the spent fuel pool storage racks shall comply with the storage patterns and alignment restrictions of Figure 5.6-1 and the minimum burnup requirements of Table 5.6-1 and Table 5.6-2.

3. Fuel placed in Region 2 of the spent fuel pool storage racks shall comply with the storage patterns or allowed special arrangements of Figure 5.6-2 and the minimum burnup requirements of Table 5.6-1 and Table 5.6-2. The allowed special arrangement for fresh fuel may be repeated, provided the applicable interface requirements specified by the safety analysis are met.

4. Any fuel satisfying criteria 5.6.1.c.l, including fresh fuel, may be placed in the Region 1 cask pit storage rack.

Z Attachment to FPL letter L-2004-063 Page 8 of 10 DESIGN FEATURES CONTROL ELEMENT ASSEMBLIES 5.3.2 The reactor core shall contain 73 full length and no part length control element assemblies. The control element assemblies shall be designed and maintained In accordance with the original design provisions contained in Section 4.2.3.2 of the FSAR with allowance for normal degradation pursuant to the applicable Surveillance Requirements.

5.4 REACTOR COOLANT SYSTEM DESIGN PRESSURE AND TEMPERATURE 5.4.1 The reactor coolant system Is designed and shall be maintained:

a.

In accordance with the code requirements specified In Section 5.2 of the FSAR with allowance for normal degradation pursuant to the applicable Surveillance Requirements,

b.

For a pressure of 2485 psig, and

c.

For a temperature of 6500F, except for the pressurizer which is 7000F.

VOLUME 5.4.2 The total water and steam volume of the reactor coolant system is 11,100 + 180 cubic feet at a nominal T,,, of 5670F, when not accounting for steam generator tube plugging.

5.5 EMERGENCY CORE COOLING SYSTEMS 5.5.1 The emergency core cooling systems are designed and shall be maintained In accordance with the original design provisions contained In Section 6.3 of the FSAR with allowance for normal degradation pursuant to the applicable Surveillance Requirements.

5.6 FUEL STORAGE CRITICALITY 5.6.1.a The spent fuel pool and spent fuel storage racks shall be maintained with:

1.

kt, less than 1.0 when fully flooded with unborated water, which Includes an allowance for biases and uncertainties as described in Section 9.1 of the Updated Final Safety Analysis Report.

2.

A nominal 10.12 inches center to center distance between fuel assemblies in Region I of the spent fuel pool storage racks, a nominal 10.30 inches center to center distance between fuel assemblies In the Region 1 cask pit storage rack, and a nominal 8.86 inches center to center distance between fuel assemblies In Region 2 of the spent fuel pool storage racks.

ST. LUCIE - UNIT 1 5-5 Amendment No. 22. 2X. 75, 4.

445,4663.

Attachment to FPL letter L-2004-063 Page 9 of 10 DESIGN FEATURES CRITICALITY (Continued)

3.

A keff less than or equal to 0.95 when flooded with water containing 500 ppm boron, including an allowance for biases and uncertainties as described in Section 9.1 of the Updated Final Safety Analysis Report.

4.

For storage of enriched fuel assemblies, requirements of Criteria 1 and 3 shall be met by positioning fuel in the spent fuel storage racks consistent with the requirements of Specification 5.6.1.c.

5.

Vessel Flux Reduction Assemblies (VFRAs), as defined in Section 9.1 of the Updated Final Safety Analysis Report, may be placed in any allowable fuel storage location.

6.

Fissile material, not contained In a fuel assembly lattice, shall be stored in accordance with the requirements of Criteria I and 3.

b. The Region I cask pit storage rack shall contain neutron absorbing material (Boral) between stored fuel assemblies when Installed In the spent fuel pool.

c. Loading of spent fuel storage racks shall be controlled as described below. Criteria 2 and 3 do not apply to the Region 1 cask pit storage rack.

1.

The maximum initial planar average U-235 enrichment of any fuel assembly inserted In a spent fuel storage rack shall be less than or equal to 4.5 weight percent.

2.

Fuel placed In Region I of the spent fuel pool storage racks shall comply with the storage patterns and alignment restrictions of Figure 5.6-1 and the minimum bumup requirements of Table 5.6-1 and Table 5.6-2.

3.

Fuel placed in Region 2 of the spent fuel pool storage racks shall comply with the storage patterns or allowed special arrangements of Figure 5.6-2 and the minimum bumup requirements of Table 5.6-1 and Table 5.6-2. The allowed special arrangement for fresh fuel may be repeated, provided the applicable interface requirements specified by the safety analysis are met.

4.

Any fuel satisfying criteria 5.6.1.c.1, including fresh fuel, may be placed in the Region I cask pit storage rack.

d. The new fuel storage racks are designed for dry storage of unirradiated fuel assemblies having a U-235 enrichment less than or equal to 4.5 weight percent, while maintaining a k.ff of less than or equal to 0.98 under the most reactive condition.

ST. LUCIE - UNIT I 5-6 Amendment No. 47-22.24,34, 7S, ",

2,

'Es Attachment to FPL letter L-2004-063 Page 10 of 10 DESIGN FEATURES DRAINAGE 5.6.2 The fuel pool Is designed and shall be maintained to prevent inadvertent draining of the pool below elevation 56 feet.

CAPACITY 5.6.3 The spent fuel pool storage racks are designed and shall be maintained with a storage capacity limited to no more than 1706 fuel assemblies, and the cask pit storage rack is designed and shall be maintained with a storage capacity limited to no more than 143 fuel assemblies. The total Unit I spent fuel pool and cask pit storage capacity is limited to no more than 1849 fuel assemblies.

5.7 SEISMIC CLASSIFICATION 5.7.1 Those structures, systems and components identified as seismic Class I in Section 3.2.1 of the FSAR shall be designed and maintained to the original design provisions contained In Section 3.7 of the FSAR with allowance for normal degradation pursuant to the applicable Surveillance Requirement.

5.8 METEOROLOGICAL TOWER LOCATION 5.8.1 The meteorological tower location shall be as shown on Figure 5.1-1.

5.9 COMPONENT CYCLE OR TRANSIENT LIMITS 5.9.1 The components Identified in Table 5.9-1 are designed and shall be maintained within the cyclic or transient limits of Table 5.9-1.

ST. LUCIE - UNIT 1 5-6a Amendment No. 9,.