ML050600428

Amendment, Revision of TS Section 2.3(4) & TS Section 3.6(2)d.(i)

ML050600428
Person / Time
Site:	Fort Calhoun
Issue date:	03/01/2005
From:	Wang A NRC/NRR/DLPM/LPD4
To:	Ridenoure R Omaha Public Power District
Wang A, NRR/DLPM, 415-1445
Shared Package
ML050600431	List: ML050600428 ML050610222
References
TAC MC3214
Download: ML050600428 (10)

Text

March 1, 2005 Mr. R. T. Ridenoure Division Manager - Nuclear Operations Omaha Public Power District Fort Calhoun Station FC-2-4 Adm.

Post Office Box 550 Fort Calhoun, NE 68023-0550

SUBJECT:

FORT CALHOUN STATION, UNIT NO. 1 - ISSUANCE OF AMENDMENT RE: (TAC NO. MC3214)

Dear Mr. Ridenoure:

The Commission has issued the enclosed Amendment No. 232 to Renewed Facility Operating License No. DPR-40 for the Fort Calhoun Station, Unit No. 1. The amendment consists of changes to the Technical Specifications (TS) in response to your application dated May 21, 2004, as supplemented on October 29, and December 16, 2004.

The amendment revises TS Section 2.3(4), "Emergency Core Cooling System - Trisodium Phosphate (TSP)," regarding the volume and form of the TSP and TS Section 3.6(2)d.(i),

"Safety Injection and Containment Cooling Systems Tests," regarding the surveillance requirement for the TSP volume.

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

Sincerely,

/RA/

Alan B. Wang, Project Manager, Section 2 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-285

Enclosures:

1. Amendment No. 232 to DPR-40

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

March 1, 2005 Mr. R. T. Ridenoure Division Manager - Nuclear Operations Omaha Public Power District Fort Calhoun Station FC-2-4 Adm.

Post Office Box 550 Fort Calhoun, NE 68023-0550

SUBJECT:

FORT CALHOUN STATION, UNIT NO. 1 - ISSUANCE OF AMENDMENT RE: (TAC NO. MC3214)

Dear Mr. Ridenoure:

The Commission has issued the enclosed Amendment No. 232 to Renewed Facility Operating License No. DPR-40 for the Fort Calhoun Station, Unit No. 1. The amendment consists of changes to the Technical Specifications (TS) in response to your application dated May 21, 2004, as supplemented on October 29, and December 16, 2004.

The amendment revises TS Section 2.3(4), "Emergency Core Cooling System - Trisodium Phosphate (TSP)," regarding the volume and form of the TSP and TS Section 3.6(2)d.(i),

"Safety Injection and Containment Cooling Systems Tests," regarding the surveillance requirement for the TSP volume.

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

Sincerely,

/RA/

Alan B. Wang, Project Manager, Section 2 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-285 DISTRIBUTION:

PUBLIC GHill (2)

Enclosures:

1. Amendment No. 232 to DPR-40 PDIV-2 Reading

2. Safety Evaluation RidsNrrDlpmPdiv (HBerkow)

RidsNrrPMAWang cc w/encls: See next page RidsNrrLALFeizollahi RidsOgcRp RidsACRSACNWMailCenter RidsRegion4MailCenter(M. Hay)

TBoyce TS: ML050610222 NRR-100 RidsNrrDlpmPdiv2 (RGramm)

ACCESSION NO.: ML050600428 PKG.: ML050600431 NRR-058 OFFICE PDIV-2/PM PDIV-2/LA EMCB: DE OGC Nlo PDIV-2/SC NAME AWang:sp LFeizollahi:lxf1 LLund APH RGramm DATE 2/24/05 2/24/05 2/23/05 2/25/05 3/1/05 DOCUMENT NAME: E:\Filenet\ML050600428.wpd w/comments OFFICIAL RECORD COPY

OMAHA PUBLIC POWER DISTRICT DOCKET NO. 50-285 FORT CALHOUN STATION, UNIT NO. 1 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No.232 License No. DPR-40

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

A. The application for amendment by the Omaha Public Power District (the licensee) dated May 21, 2004, as supplemented on October 29, and December 16, 2004, 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 license 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, Renewed Facility Operating License No. DPR-40 is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 3.B. of Facility Operating License No. DPR-40 is hereby amended to read as follows:

B. Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 232, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.

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

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

Robert A. Gramm, Chief, Section 2 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications Date of Issuance: March 1, 2005

ATTACHMENT TO LICENSE AMENDMENT NO. 232 RENEWED FACILITY OPERATING LICENSE NO. DPR-40 DOCKET NO. 50-285 Replace the following pages of the Appendix A Technical Specifications with the attached revised pages. The revised pages are identified by amendment number and contain vertical lines indicating the areas of change.

REMOVE INSERT TOC - Page 8 TOC - Page 8 2.3 - Page 4 2.3 - Page 4 2.3 - Page 6 2.3 - Page 6

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2.3 - Page 8 3.6 - Page 2 3.6 - Page 2 3.6 - Page 6 3.6 - Page 6

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3.6 - Page 7

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 232 TO RENEWED FACILITY OPERATING LICENSE NO. DPR-40 OMAHA PUBLIC POWER DISTRICT FORT CALHOUN STATION, UNIT NO. 1 DOCKET NO. 50-285

1.0 INTRODUCTION

By application dated May 21, 2004 (ML041470121), as supplemented on October 29, 2004 (ML043030426), and December 16, 2004 (ML043520417), Omaha Public Power District (OPPD/the licensee) requested changes to the Technical Specifications (Appendix A to Renewed Facility Operating License No. DPR-40) for the Fort Calhoun Station, Unit No. 1 (FCS).

The amendment revises Technical Specifications (TS) Section 2.3(4), "Emergency Core Cooling System - Trisodium Phosphate (TSP)," and TS Section 3.6(2)d.(i), "Safety Injection and Containment Cooling Systems Tests." Specifically, the licensees proposed changes consist of deleting the requirement that the trisodium phosphate (TSP) be of the "dodecahydrate" form and instead specifying that hydrated TSP (45-57 percent moisture content) is required. In addition, instead of having a fixed volume of TSP required, the licensee proposed a new methodology in which the volume of TSP required will vary throughout the operating cycle as determined by a new TS Figure 2-3.

The additional information provided in the supplemental letters dated October 29, 2004 and December 16, 2004, did not expand the scope of the application as noticed and did not change the Nulear Regulatory Commission (NRC) staff's original proposed no significant hazards consideration determination published in the Federal Register on June 8, 2004 (69 FR 32075).

2.0 REGULATORY EVALUATION

OPPD has applied for a license amendment to its TSs 2.3(4) and 3.6 under 10 CFR 50.90. The changes are consistent with the applicable regulatory recommendations in NUREG 0800, Section 6.5.2, "Containment Spray as a Fission Product Cleanup System." Subsection II.1.g specifies that the pH of all solutions in the containment sump and all additives for reactivity control, fission product removal, or other purposes (boric acid) should be maintained at a level high enough to assure that significant long-term iodine re-evolution does not occur. Long-term iodine retention may be assumed only when the equilibrium sump solution pH, after mixing with the primary coolant and emergency core cooling system injection sources, is above 7.0.

The FCS was licensed in accordance with the 70 draft General Design Criteria (GDC) published for comment in the Federal Register (32 FR 10213) on July 11, 1967. The 70 draft GDC are

contained in Appendix G of the FCS Updated Safety Analysis Report. The acceptance criteria for the fission product cleanup function of the containment spray system are based on meeting the relevant requirements of the following regulations:

Draft GDC 42, "Engineered Safety Features Components Capability," as it relates to containment atmosphere cleanup systems being designed to control fission product releases to the reactor containment following postulated accidents.

Draft GDC 62, "Inspection of Air Clean-up Systems," as it relates to containment atmosphere cleanup systems being designed to permit periodic inspections.

Draft GDC 64, "Testing of Air Clean-up Systems," as it relates to containment atmosphere cleanup systems being designed for appropriate periodic functional testing.

The proposed amendment is in compliance with the draft GDCs.

OPPD has stated that the technical analysis and risk information provided in its submittal satisfies all regulatory requirements and guidance concerning the type and volume of active TSP required in the containment sump to ensure post loss-of-coolant accident (LOCA) recirculation water maintains a pH greater than or equal to 7.0 but less than or equal to 7.5.

Increasing the pH greater than 7.5 would negatively impact equipment environmental qualification (EEQ) as required by 10 CFR 50.49 and hydrogen generation design basis assumptions by making the containment sump too basic.

3.0 TECHNICAL EVALUATION

The license amendment for the FCS consists of deleting the requirement that the TSP be of the dodecahydrate form and instead requiring a hydrated TSP (45-57 percent moisture content).

This change will make TS 2.3(4) consistent with NUREG-1432, Revision 2, "Standard Technical Specifications Combustion Engineering Plants," which does not require a specific type of TSP.

In addition, the licensee proposes that instead of having a fixed volume requirement of TSP provided in the TSs, a new figure (2-3) will be added to its TSs that provides a required volume of TSP that changes as the critical boron concentration gradually decreases. The surveillance requirement of TS 3.6(2).d.(i) is revised to require a volume of TSP that is within the area of acceptable operation of TS Figure 2-3. The purpose of this amendment is to prevent the licensee from entering a Limiting Condition for Operation caused by the effects of densification at some future time.

A variety of acids and bases are produced in containment after a LOCA. The pH value of the containment sump water will depend on the concentration of the chemical species dissolved in it and on the buffering action of TSP. There are two considerations for determining the pH of the containment sump after a LOCA. In order to prevent release of elemental iodine to the containment atmosphere after a LOCA, the sump pH must be maintained greater than or equal to 7.0. In addition, for EEQ considerations the pH must be maintained less than or equal to 7.5.

The TSP baskets have a maximum capacity of 131.9 ft3, which will provide the correct pH for the containment sump after a LOCA.

After a LOCA, the containment sump is mostly filled with water coming from the systems containing boric acid: safety injection refueling water tank (SIRWT), safety injection tanks (SITs), boric acid storage tanks (BASTs) and the reactor coolant system (RCS). As the water starts accumulating in containment, the water itself dissolves the TSP contained in the baskets.

Mixing is achieved as the solution is continuously recirculated. The TSP acts as a buffer to maintain the sump pH greater than or equal to 7.0 and less than or equal to 7.5. Maintaining sump water in an alkaline condition is needed for preventing dissolved radioactive iodine from being released to the containment atmosphere during the recirculation containment spray injection. In addition, keeping the sump pH at or above 7.0 will help reduce stress corrosion cracking of austenitic stainless steel components in containment. Most of the iodine leaves the damaged core in an ionic form which is readily dissolved in the sump water. However, in an acidic environment, some of it becomes converted into an elemental form which is much less soluble, causing re-evolution of iodine to the containment atmosphere.

The minimum required amount of TSP is a function of different factors: (1) cycle specific hot zero power critical boron concentration (HZP CBC); (2) boron concentrations, maximum volumes and temperatures of the RCS, SIRWT, SITs and BASTs; and (3) the acids generated from the degradation of electrical cable jackets and the irradiation of water and air in the containment. Future fuel and core designs are expected to increase the RCS HZP CBC at the beginning of cycle (BOC). The current licensees TSs require a minimum active TSP volume of

$126 ft3, which represents the densified amount of TSP in the baskets. The storage baskets have a maximum capacity of 131.9 ft3. Because of the increase in the HZP CBC, an increase in the TSP volume at the BOC would be required to maintain a pH $7.0. Currently, the licensee fills up the baskets to their maximum capacity at the BOC to compensate for the effects of densification (because of the high humidity existing in the containment, the TSP tends to agglomerate, thereby causing the volume to decrease and the density to increase, although the mass remains the same). Licensee test results have shown that densification can account for a 5 percent loss of the volume of TSP over the operating cycle. Raising the minimum TSP requirement for the entire cycle would reduce the margin (volume of TSP above that required by TSs) between the maximum capacity of the baskets and the minimum TSP volume required by TSs. This reduction could result in the volume of TSP at the end of cycle (EOC) not to be in compliance with the TSs.

In order to prevent this from happening, the licensee considered increasing the amount of TSP in containment by adding an additional basket. Even though this solution would work at the BOC when the HZP CBC was significantly higher, this could result in a pH greater than 7.5 at the EOC when HZP CBC was significantly lower. This would negatively impact EEQ and hydrogen generation design basis assumptions by making the containment sump too basic.

This option was rejected by the licensee.

Another option analyzed by the licensee consisted in, rather than having a required fixed volume of TSP, use of a new figure (2-3) will allow the required TS volume of TSP to change as the critical boron concentration gradually decreases throughout the operating cycle. Having the required volume of TSP trending downward during the operating cycle with decreasing HZP CBC will provide an adequate margin to account for densification and will help maintain the sump pH between 7.0 and 7.5. This option doesnt imply that the existent TSP volume will actually decrease throughout the operating cycle. In a letter dated August 27, 2004 (ML042430027), the staff asked the licensee to clarify if other mechanisms causing loss of TSP

besides densification existed and how were these incorporated in the process of construction of the graph in Figure 2-3. By letter dated October 29, 2004, the licensee responded that no credible material loss mechanisms have been identified other than densification. Therefore, only a reduction of 5 percent in the volume of TSP is expected at the EOC.

Even though there is a loss of volume due to densification, the TSP mass remains the same throughout the operating cycle. If there is no mass loss of the TSP, the amount of TSP corresponding to 131.9 ft3 would produce a low pH value at the BOC when boric acid concentration is high and a high pH value at the EOC when boric acid concentration is low. In a letter dated August 27, 2004, the staff asked the licensee to clarify if a high pH value at the EOC would have a negative impact on the EEQ. By letter dated October 29, 2004, the licensee responded that the EEQ is maintained with the current mass equivalent amount of TSP in containment. Furthermore, in a letter dated December 16, 2004, the licensee indicated that an upper limit of 135.71 ft3 is the total effective volume of TSP allowed in the baskets. The total effective TSP volume, as defined by the licensee, is the cumulative volume of the TSP initially placed into the baskets and the volume of TSP added to top-off the baskets (due to the densification) during subsequent refueling outages. The licensee keeps records of the cumulative volume of TSP added to the baskets from cycle to cycle in order to prevent exceeding the total effective volume. This limit will ensure that EEQ requirements are maintained by assuring that containment sump pH does not exceed 7.5 should a LOCA occur at the end of cycle. The licensees compliance with the proposed figure should ensure that the containment sump pH stays greater than or equal to 7.0 but less than or equal to 7.5 to meet EEQ and hydrogen generation design basis objectives.

The licensee also proposes to delete the TS requirement that the TSP be of the dodecahydrate form and instead specify that hydrated TSP, with a moisture content of 45-57 percent is required. The licensee will incorporate information from the Basis of 3.5.5 of NUREG-1432, Revision 2, by stating: "The hydrated form (45-57 percent moisture) of TSP is used because of the high humidity in the containment building during normal operation. Since the TSP is hydrated, it is less likely to absorb large amounts of water from the humid atmosphere and will undergo less physical and chemical change than the anhydrous form of TSP." In a letter dated July 8, 2004 (ML041950091), the staff asked the licensee whether hydrated forms of TSP have different densities and, if any difference exists, to provide the value used in its calculations. In a letter dated October 29, 2004, the licensee responded that the most limiting combination of parameters as specified in the procurement specifications have been used in its calculation, thus adding more conservatism to the calculation.

After an accident, the pH of the containment sump water depends on the amounts of acidic and basic chemical materials either released from the damaged core or generated in containment and subsequently dissolved in the sump water. If the pH falls below 7, radioactive iodine could be released to the containment atmosphere. The addition of a buffering solution will keep the water pH at or above 7, therefore preventing the iodine from being released. The licensee uses TSP held in baskets throughout the containment as a pH buffer. The licensees proposed amendment stating that the TSP requirement be in a downward trend as the HZP CBC decreases will still ensure that at any time during the operating cycle the TSP present in the baskets will help prevent the sump water pH from falling below 7. The only anticipated decrease of the volume of TSP in the baskets is due to densification, which is already accounted for in the licensees calculations, but the mass is expected to remain the same throughout the operating cycle, thus ensuring the sump pH will remain at or above 7 throughout the duration of the accident.

Based on the above, the staff concludes that proposed TS changes are acceptable.

OPPD has revised Bases Sections 2.3 and 3.6 to reflect the new TS requirements. The staff has reviewed these Bases changes and has no objections to them.

4.0 STATE CONSULTATION

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

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents 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 the amendment involves no significant hazards consideration and there has been no public comment on such finding (69 FR 32075). Accordingly, the 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 the amendment.

6.0 CONCLUSION

The Commission 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 the amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: Y. Diaz-Castillo Date: March 1, 2005

Ft. Calhoun Station, Unit 1 cc:

Winston & Strawn Mr. Daniel K. McGhee ATTN: James R. Curtiss, Esq. Bureau of Radiological Health 1400 L Street, N.W. Iowa Department of Public Health Washington, DC 20005-3502 401 SW 7th Street, Suite D Des Moines, IA 50309 Chairman Washington County Board of Supervisors P.O. Box 466 Blair, NE 68008 Mr. John Hanna, Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 310 Fort Calhoun, NE 68023 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Ms. Sue Semerera, Section Administrator Nebraska Health and Human Services Systems Division of Public Health Assurance Consumer Services Section 301 Centential Mall, South P.O. Box 95007 Lincoln, NE 68509-5007 Mr. David J. Bannister, Manager Fort Calhoun Station Omaha Public Power District Fort Calhoun Station FC-1-1 Plant P.O. Box 550 Fort Calhoun, NE 68023-0550 Mr. John B. Herman Manager - Nuclear Licensing Omaha Public Power District Fort Calhoun Station FC-2-4 Adm.

P.O. Box 550 Fort Calhoun, NE 68023-0550