ML071110006

Issuance of Amendment Refueling Water Storage Tank Boron Concentration

ML071110006
Person / Time
Site:	Kewaunee
Issue date:	05/18/2007
From:	Chernoff M NRC/NRR/ADRO/DORL/LPLIII-1
To:	Christian D Dominion Energy Kewaunee
Kuntz, Robert , NRR/DLPM, 415-3733
References
TAC MD2456
Download: ML071110006 (13)

Text

May 18, 2007 Mr. David A. Christian Senior Vice President and Chief Nuclear Officer Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711

SUBJECT:

KEWAUNEE POWER STATION - ISSUANCE OF AMENDMENT RE:

REFUELING WATER STORAGE TANK BORON CONCENTRATION (TAC NO.

MD2456)

Dear Mr. Christian:

The U.S. Nuclear Regulatory Commission has issued the enclosed Amendment No. 192 to Facility Operating License No. DPR-43 for the Kewaunee Power Station. This amendment revises the Technical Specifications (TSs) in response to your application dated June 28, 2006, as supplemented by letter dated November 2, 2006.

The amendment revises TS 3.3.b.3.B and TS 3.3.b.4.A to increase the minimum required boron concentration in the refueling water storage tank from 2400 parts per million (ppm) to 2500 ppm.

A copy of the Safety Evaluation is also enclosed. The Notice of Issuance will be included in the Commission's next regular biweekly Federal Register notice.

Sincerely,

/RA/

Margaret H. Chernoff, Senior Project Manager Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-305

Enclosures:

1. Amendment No. 192 to License No. DPR-43

2. Safety Evaluation cc w/encls: See next page

Mr. David A. Christian May 18, 2007 Senior Vice President and Chief Nuclear Officer Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711

SUBJECT:

KEWAUNEE POWER STATION - ISSUANCE OF AMENDMENT RE:

REFUELING WATER STORAGE TANK BORON CONCENTRATION (TAC NO.

MD2456)

Dear Mr. Christian:

The U.S. Nuclear Regulatory Commission has issued the enclosed Amendment No. 192 to Facility Operating License No. DPR-43 for the Kewaunee Power Station. This amendment revises the Technical Specifications (TSs) in response to your application dated June 28, 2006, as supplemented by letter dated November 2, 2006.

The amendment revises TS 3.3.b.3.B and TS 3.3.b.4.A to increase the minimum required boron concentration in the refueling water storage tank from 2400 parts per million (ppm) to 2500 ppm.

A copy of the Safety Evaluation is also enclosed. The Notice of Issuance will be included in the Commission's next regular biweekly Federal Register notice.

Sincerely,

/RA/

Margaret H. Chernoff, Senior Project Manager Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-305

Enclosures:

1. Amendment No. 192 to License No. DPR-43

2. Safety Evaluation cc w/encls: See next page DISTRIBUTION:

PUBLIC LPL3-1 r/f RidsNrrDorlLpl3-1 RidsNrrPMMChernoff RidsNrrLATHarris RidsOGCRp RidsAcrsAcnwMailCenter RidsNrrDciCsgb G. Hill, OIS RidsNrrDorlDpr RidsRgn3MailCenter RidsNrrDssSrxb ADAMS ACCESSION NO.: ML071110006 OFFICE LPL3-1/PM LPL3-1/LA CSGB/BC SRXB/BC OGC LPL3-1/BC NAME MChernoff THarris AHiser- GCranston JBiggins LRaghavan memo dtd. memo dtd.

DATE 5/18/07 5/17/07 9 /28/06 3/21/07 5/11/07 5/18/07 OFFICIAL RECORD COPY

Kewaunee Power Station cc:

Resident Inspectors Office Ms. Lillian M. Cuoco, Esq.

U.S. Nuclear Regulatory Commission Senior Counsel N490 Hwy 42 Dominion Resources Services, Inc.

Kewaunee, WI 54216-9510 Millstone Power Station Building 475, 5th Floor Regional Administrator, Region III Rope Ferry Road U.S. Nuclear Regulatory Commission Waterford, CT 06385 Suite 210 2443 Warrenville Road Lisle, IL 60532-4351 Ms. Leslie N. Hartz Dominion Energy Kewaunee, Inc.

Kewaunee Power Station N 490 Highway 42 Kewaunee, WI 54216 Mr. Chris L. Funderburk Director, Nuclear Licensing and Operations Support Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711 Mr. Thomas L. Breene Dominon Energy Kewaunee, Inc.

Kewaunee Power Station N490 Highway 42 Kewaunee, WI 54216

DOMINION ENERGY KEWAUNEE, INC.

DOCKET NO. 50-305 KEWAUNEE POWER STATION AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 192 License No. DPR-43

1. The U.S. Nuclear Regulatory Commission (the Commission) has found that:

A. The application for amendment by Dominion Energy Kewaunee, Inc. dated June 28, 2006 as supplemented by letter dated November 2, 2006, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I;

B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Facility Operating License No. DPR-43 is hereby amended to read as follows:

(2) Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 192, are hereby incorporated in the license. The licensees shall operate the facility in accordance with the Technical Specifications.

3. This license amendment is effective as of its date of issuance and shall be implemented within 60 days of the date of issuance.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

L. Raghavan, Chief Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Facility Operating License and Technical Specifications Date of Issuance: May 18, 2007

ATTACHMENT TO LICENSE AMENDMENT NO. 192 FACILITY OPERATING LICENSE NO. DPR-43 DOCKET NO. 50-305 Replace the following page of the Facility Operating License No. DPR-43 with the attached revised page. The changed area is identified by a marginal line.

REMOVE INSERT Page 3 Page 3 Replace the following page of the Appendix A Technical Specifications with the attached revised page. The revised page is identified by amendment number and contains marginal lines indicating the areas of change.

REMOVE INSERT 3.3-3 3.3-3

C. This license shall be deemed to contain and is subject to the conditions specified in the following Commission regulations in 10 CFR, Chapter 1: (1) Part 20, Section 30.34 of Part 30, Section 40.41 of Part 40, Section 50.54 and 50.59 of Part 50, and Section 70.32 of Part 70, (2) is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect, and (3) is subject to the additional conditions specified or incorporated below:

(1) Maximum Power Level The licensee is authorized to operate the facility at steady-state reactor core power levels not in excess of 1772 megawatts (thermal).

(2) Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 192, are hereby incorporated in the license. The licensee shall operate the facility In accordance with the Technical Specifications.

(3) Fire Protection The licensee shall implement and maintain in effect all provisions of the approved Fire Protection Program as described in the licensee's Fire Plan, and as referenced in the Updated Safety Analysis Report, and as approved in the Safety Evaluation Reports, dated November 25, 1977, and December 12, 1978 (and supplement dated February 13, 1981) subject to the following provision:

The licensee may make changes to the approved Fire Protection Program without prior approval of the Commission, only if those changes would not adversely affect the ability to achieve and maintain safe shutdown in the event of a fire.

(4) Physical Protection The licensee shall fully implement and maintain in effect all provisions of the Commission-approved physical security, training and qualification, and safeguards contingency plans including amendments made pursuant to provisions of the Miscellaneous Amendments and Search Requirements revisions to 10 CFR 73.55 (51 FR 27817 and 27822) and to the authority of 10 CFR 50.90 and 10 CFR 50.54(p). The combined set of plans, which contain Safeguards Information protected under 10 CFR 73.21, is entitled: Nuclear Management Company Kewaunee Nuclear Power Plant Physical Security Plan (Revision 0)" submitted by letter dated October 18, as supplemented by letter dated October 21, 2004, July 26, 2005, and May 15, 2006.

(5) Fuel Burnup The maximum rod average burnup for any rod shall be limited to 60 GWD/MTU until completion of an NRC environmental assessment supporting an increased limit.

Amendment No. 192 Revised by letter dated February 8, 2007 3

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATING TO AMENDMENT NO. 192 TO FACILITY OPERATING LICENSE NO. DPR-43 DOMINION ENERGY KEWAUNEE, INC.

KEWAUNEE POWER STATION DOCKET NO. 50-305

1.0 INTRODUCTION

By application dated June 28, 2006 (Agencywide Documents Access & Management System (ADAMS) Accession No. ML061800307), as supplemented by letter dated November 2, 2006 (ADAMS Accession No. ML063070064), Dominion Energy Kewaunee, Inc. (the licensee) requested changes to the Technical Specifications (TSs) for the Kewaunee Power Station (Kewaunee). The licensees supplementary submittal dated November 2, 2006, provided clarifying information that did not change the scope of the proposed amendment as described in the original notice of proposed action published in the Federal Register and did not change the initial proposed no significant hazards determination.

Kewaunee experienced two prolonged shutdown periods during Cycle 27. Because of these shutdown periods, the fuel in the core did not experience the burnup anticipated when Cycles 27 and 28 were designed. Therefore, Cycle 28 will have more reactivity than originally anticipated. The licensee completed an analysis that supports the conclusion that this change is not required to support startup of Kewaunee following the current refueling outage, but increasing the minimum required refueling water storage tank boron concentration is still advisable for future reload cores that may challenge this limitation. Therefore, the licensee proposed the following revisions to TS 3.3.b, Emergency Core Cooling System :

TS 3.3.b.3.B Current TS requirement: The Refueling Water Storage Tank [RWST] has a boron concentration of at least 2400 ppm [parts per million] .

Proposed TS requirement: The Refueling Water Storage Tank has a boron concentration of at least 2500 ppm.

TS 3.3.b.4.A Current TS requirement: The calculated Refueling Water Storage Tank boron concentration may be < 2400 ppm for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

Proposed TS requirement: The calculated Refueling Water Storage Tank boron concentration may be < 2500 ppm for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

2.0 REGULATORY EVALUATION

The regulations in Title 10, of the Code of Federal Regulations Section 50 Part 46 (10 CFR 50.46), Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors (Ref. 4) and 10 CFR Part 50, Appendix K, ECCS Evaluation Models (Ref. 5) specify the requirements for the design and analysis of emergency core cooling systems (ECCS).

These regulations are in place to ensure adequate core cooling following a loss-of-coolant accident (LOCA) such that specified acceptance criteria are satisfied. The specified acceptance criteria include peak clad temperature, total cladding oxidation, total hydrogen generation, maintaining a coolable core geometry and ensuring adequate long-term core cooling. The applicable acceptance criterion for the proposed license amendment is the long-term core cooling criterion. This criterion requires that the core temperature be maintained at an acceptably low value and that decay heat be removed for the extended period of time required by the long-lived radioactivity remaining in the core. The minimum boron requirement for the RWST ensures that sufficient negative reactivity is injected into the core to counteract any positive increase in reactivity caused by reactor coolant system cool-down.

3.0 TECHNICAL EVALUATION

Kewaunee is a two-loop Westinghouse Pressurized Water Reactor. Emergency core cooling is provided by the ECCS whose systems, structures, and components operate in three modes:

passive accumulator injection, active safety injection (SI), and containment sump recirculation.

For active SI, an ECCS actuation signal sends an open signal to the required Safety Injection System Isolation valves, and starts the SI pumps (high-head) and the residual heat removal (RHR) pumps (low-head). The high-head SI pumps and the low-head RHR pumps take suction from the RWST. The RWST contains borated water at a boron concentration of at least the minimum TS required concentration. The two RHR (low-head) pumps are used to inject borated water at low pressure to the reactor coolant system. When the water in the RWST is depleted, the RHR pumps are manually aligned to recirculate fluid from the containment sump and return it to the reactor.

The proposed change would increase the minimum boron concentration in the RWST from 2400 ppm to 2500 ppm. The maximum boron concentration will remain at a value of 2625 ppm.

The licensee evaluated the impact of this change on the following:

• Non-LOCA Updated Safety Analysis Report Chapter 14 transients and accidents

• LOCA analyses

• Post-LOCA boron precipitation (analysis to confirm that boron concentrations in the post-LOCA core remain below the boric acid solubility limit)

• Post-LOCA sump boron concentration limit (evaluated for each reload core design to ensure long-term post-LOCA subcriticality)

• Post-LOCA containment spray and containment sump pH (to ensure adequate atmospheric iodine removal and retention capability, and to minimize the potential for stress and corrosion cracking of stainless steel components in containment)

• Environmental qualification of equipment installed in containment

• Margin to the temperature-dependent boric acid solution solubility limit The Nuclear Regulatory Commission staff reviewed each of the analyses listed above. The

only analysis that was found to be impacted by the proposed change was the Post-LOCA sump boron concentration limit analysis. Details of each analysis and how each relates to the proposed change are discussed below.

3.1 Non-LOCA Transients and Accidents All of the non-LOCA transient and accident analyses were considered. The only non-LOCA transient or accident analysis that was found to rely on the RWST borated water for reactor shutdown was the Main Steamline Break accident analysis. This accident analysis requires the injection of ECCS water in order to provide accident mitigation. The ECCS water is borated, and is injected into the reactor coolant system (RCS) to maintain core inventory for core cooling, and to ensure that the reactor is adequately shutdown. An increase in the minimum boron concentration of the RWST from 2400 ppm to 2500 ppm will result in a higher RCS post-accident boron concentration. Therefore, this analysis would remain bounding and valid for the proposed increase in RWST minimum boron concentration.

3.2 LOCA Analyses Both small-break (SBLOCA) and large-break LOCA (LBLOCA) analyses were considered. For the LBLOCA, the core is kept subcritical during the blowdown phase by the large amount of negative reactivity due to the void coefficient. When the refill and reflood phases begin, the negative reactivity from the void coefficient becomes less significant because it begins to be replaced by boron as the primary source of negative reactivity as the core is gradually filled with borated water. The LBLOCA analysis shows that the peak cladding temperature is reached before the time when the boron becomes significant in maintaining core shutdown. Therefore, the LBLOCA core response analysis remains bounding and valid.

For the SBLOCA analysis, the boron concentration required to achieve the level of negative reactivity necessary to assure shutdown margin is significantly lower than the concentration required for shutdown during a LBLOCA. The increase in RWST boron concentration would provide additional conservatism for the SBLOCA. Therefore, the SBLOCA core response analysis also remains bounding and valid.

3.3 Post-LOCA Boron Precipitation Boron precipitation is more likely to occur during a LOCA when higher initial boron concentrations are present in the RCS and RWST. Even though the proposed change would increase the minimum RWST boron concentration from 2400 ppm to 2500 ppm, the post-LOCA boron precipitation analysis conservatively assumes injected ECCS fluid at the maximum RWST boron concentration of 2625 ppm. Therefore, the post-LOCA boron precipitation analysis would also remain bounding and valid.

3.4 Post-LOCA Sump Boron Concentration Limit It is necessary to have a sufficiently high boric acid concentration in the containment sump mixture following a LOCA in order to ensure that the reactor remains subcritical. Therefore, this analysis is redone for every new core configuration, conservatively considering the maximum amount of reactivity that the core will experience over its lifetime (usually occurring at the beginning of cycle). The maximum amount of reactivity for the core during Cycle 28 was

expected to be higher than that of Cycle 27. When this analysis was redone for Cycle 28, the results showed that a minimum RWST boron concentration of 2400 ppm was not sufficient for the maximum amount of reactivity expected during Cycle 28. Therefore, the analysis was re-considered with a new minimum boron concentration of 2500 ppm. The results of this analysis were found to be satisfactory.

The two tables below show the results of both Post-LOCA Sump Boron Concentration Limit analyses. Table 1 shows the results considering a minimum RWST boron concentration of 2400 ppm, and Table 2 shows the results considering a minimum RWST boron concentration of 2500 ppm. The results from Table 1 (2400 ppm of boron) show that the maximum post-LOCA core critical boron concentration exceeds the post-LOCA boron concentration limit, while the results from Table 2 (2500 ppm of boron) show that there is enough boron concentration to ensure post-LOCA subcriticality by a margin of +19.

It should be noted that the results shown in Table 1 and Table 2 were from an earlier calculation. Since that time, the same analysis was performed again with better estimates of cycle reactivity. The results of the updated analysis concluded that a minimum RWST boron concentration of 2400 ppm was sufficient, but the proposed increase to 2500 ppm was still desired for future cycles that could possibly challenge this limitation.

Table 1. Post-LOCA Sump Boron Concentration Analysis Results (2400 ppm)

RWST Boron Concentration: 2400 ppm Condition Results Min. Pre-LOCA 1419 ppm Post-LOCA Limit 2185 ppm Max. Post-LOCA Core Critical (68oF) 2208 ppm Max. Post-LOCA Core Critical (212oF) 2241 ppm Margin -56

Table 2. Post-LOCA Sump Boron Concentration Analysis Results (2500 ppm)

RWST Boron Concentration: 2500 ppm Condition Results Min. Pre-LOCA 1419 ppm Post-LOCA Limit 2260 ppm Max. Post-LOCA Core Critical (68oF) 2208 ppm Max. Post-LOCA Core Critical (212oF) 2241 ppm Margin +19 3.5 Post-LOCA Containment Spray and Containment Sump pH Analysis Following a LOCA, fluid from the RWST, the Caustic Pipe or Chemical Addition Tank (CAT),

the Safety Injection Accumulators, the High Head Safety Injection System Piping (SI Piping),

the Low Head/Residual Heat Removal Piping (RHR Piping), the RCS, and potentially unborated water in the containment sump during normal operation gets mixed together and eventually end up in the containment sump. All of these volumes of fluid contain boric acid solution, except for the CAT, which contains sodium hydroxide solution. The pH of the containment spray and the containment sump needs to be kept within an acceptable range following a LOCA. The post-LOCA containment spray and containment sump pH analysis ensures adequate post-LOCA radioiodine removal and retention, and minimizes the potential for stress corrosion cracking of stainless steel components in containment. It is determined by a mass-weighted concentration of the boric acid and sodium hydroxide from each analyzed volume.

The results of Kewaunees current analysis for post-LOCA containment sump pH demonstrate that sump pH will remain within the acceptable post-LOCA sump pH range of 7.0 to 9.5, assuming upper and lower bounding values of RWST boron concentrations of 2625 ppm and 2400 ppm. This means that the lower pH value of 7.0 corresponds to a RWST boron concentration of 2625 ppm, and the upper pH value of 9.5 corresponds to a RWST boron concentration of 2400 ppm. Increasing the minimum RWST boron concentration from 2400 ppm to 2500 ppm would actually constrain the pH range more precisely, but more importantly, the results obtained from this analysis would still be within the pH range of 7.0 to 9.5.

Therefore, this analysis would still remain bounding and valid.

3.6 Environmental Equipment Qualification The environmental qualification of equipment located inside containment is potentially affected by the change in minimum RWST boron concentration because of the change in chemical composition of the containment spray. Containment spray is one of the environmental factors used to qualify class 1E electrical equipment to assure operation when required. This environmental factor is considered for equipment inside containment experiencing a LOCA environment. The containment spray takes boric acid solution from the RWST and sodium hydroxide solution from the CAT during injection mode of the ECCS.

Kewaunees current evaluation of containment spray considers a range of allowable and required RWST boron concentrations from 2400 ppm to 2625 ppm. The chemical composition parameter of most concern is containment spray pH. The 2400 ppm corresponds to the higher pH value and the 2625 ppm corresponds to the lower pH value. Therefore, just as in section 3.5, raising the minimum RWST boron concentration would not affect this analysis, since the results obtained from this analysis would still be within the required pH range; and, therefore, there would not be an adverse effect on the environmental qualification of equipment inside of containment.

3.7 Assessment of Boron Solubility in the RWST This analysis is used to determine if the boron contained within the volumes listed in section 3.5 will remain dissolved in solution. The maximum RWST boron concentration (2625 ppm) is used for this analysis instead of the minimum RWST boron concentration (2400 ppm) to obtain a more conservative result. Therefore, increasing the minimum RWST boron concentration from 2400 ppm to 2500 ppm would have no effect on this analysis.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Wisconsin State official was notified of the proposed issuance of the amendment. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes a surveillance requirement. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluent that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding (71 FR 43530). Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.

6.0 CONCLUSION

The NRC staff has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: K. Desai Date: May 18, 2007