ULNRC-05347, Response to Request for Additional Information Revision to Technical Specification 3.5.2, ECCS - Operating

Response to Request for Additional Information Revision to Technical Specification 3.5.2, ECCS - Operating

ML063340098
Person / Time
Site:	Callaway
Issue date:	11/22/2006
From:	Fitzgerald D AmerenUE
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
ULNRC-05347
Download: ML063340098 (8)

Text

AmerenUE Cal/away Plant PO Box 620 Fulton, MO 65251 November 22, 2006 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 ULNRC-05347 S'Ameren Ladies and Gentlemen:

II 1/7 1LEL DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.

FACILITY OPERATING LICENSE NPF-30 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REVISION TO TECHNICAL SPECIFICATION 3.5.2, "ECCS - OPERATING"

Reference:

1. ULNRC-05293, dated May 30, 2006

2. ULNRC-05194, dated September 1, 2005 Reference 1 provided Union Electric (AmerenUE) application to requesting approval of changes to Technical Specification (TS) 3.5.2, "ECCS - Operating" and TS 3.6.7, "Recirculation Fluid pH Control System" to support replacement of the containment recirculation sumps inlet trash racks and screens with strainers in response to Generic Letter 2004-02. The change to TS 3.5.2 is required to reflect the change from trash racks and screens to strainers with significantly larger effective surface area. The change to TS 3.6.7 is required to relocate the Recirculation Fluid pH Control System from the current location above the containment sump pits to alternate locations on the containment floor to allow installation of the new strainer design.

On September 21, 2006, the NRR Project Manager requested by electronic mail the following information to support the license amendment request (LAR) to revise SR 3.5.2.8.

The LAR is not changing the plant design or licensing basis. The existing trash racks and screen are safety-related and designed to perform the following safety functions in the plant safety analyses to prevent debris in the sumps from:

(1) reducing the net positive suction head (NPSH) to the emergency core cooling system (ECCS) and containment spray system (CSS) from the 0 (oo:

a subsidiary of Ameren Corporation

ULNRC-05347 November 22, 2006 Page 2 sumps such that the NPSH would remain adequate to meet the design-basis accident analyses, (2) causing the loss-of-function of any safety-related ECCS and CSS components, and (3) blocking passages in the fuel or CSS spray nozzles.

The replacement strainers are designed to perform the same safety functions of the existing trash rack and screens.

The containment recirculation sumps are located outside the secondary shield walls and, therefore, outside the zone of influence of LOCA break locations. As stated in Section 6.2.2.1.2.2 of the Callaway Plant FSAR, the containment recirculation sumps are located below concrete pads supporting the accumulator tanks so debris can not fall directly on to the strainers. The replacement of the trash racks and screens by strainers in the containment sump would not change any containment piping, or system fluid flows and pressures. The current protection of the existing trash racks and screens in the containment sump against missiles, jet impingement, and high energy pipe whip is sufficient to protect the new strainers being installed against these same events. Additional information on this issue can be found in Reference 2.

In addition, Enclosure 1 transmits the updated markup of the proposed Technical Specification Bases which incorporates the design information that was not available at the time of the original submittal.

This letter does not contain new commitments.

If you have any questions concerning this matter, please contact Dave Shafer at (314) 554-3104.

[ declare under penalty that the foregoing is true and correct.

Sincerely, Executed on: November 22, 2006 David T. Fitzgerald Manager - Regulatory Affairs BFH/

Enclosure:

1.

Markup of Technical Specification Bases

ULNRC-05347 November 22, 2006 Page 3 Mr. Bruce S. Mallett Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Jack N. Donohew (2 copies)

Licensing Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop O-7D1 Washington, DC 20555-2738 Missouri Public Service Commission Governor Office Building 200 Madison Street PO Box 360 Jefferson City, MO 65102-0360 Mr. Ron Reynolds Director Missouri State Emergency Management Agency P.O. Box 116 Jefferson City, MO 65102

ULNRC-05347 MARKUP OF TECHNICAL SPECIFICATIONS BASES (Information Only)

Recirculation Fluid pH Control System B 3.6.7 B 3.6 CONTAINMENT SYSTEMS B 3.6.7 Recirculation Fluid pH Control System BASES BACKGROUND The Recirculation Fluid pH Control System (RFPC) is a subsystem of the Containment Spray System that assists in reducing the iodine fission product inventory in the containment atmosphere resulting from a Design Basis Accident (DBA).

Radioiodine in its various forms is the fission product of primary concern in the evaluation of a DBA. It is absorbed by the spray from the containment atmosphere. To enhance the iodine absorption capacity of the recirculated spray and to maximize retention of volatile iodine species in the sumps, the sump solution is adjusted to a minimum equilibrium sump pH of 7.1 A pH of greater than 7.0 minimizes the evolution of volatile iodine species from the sump solution as well as the occurrence of chloride and caustic stress corrosion on mechanical systems and mponents.

Baskets are located within the The RFPC System includes stainless steel baskets containing trisodi recirculation paths of each phosphate crystalline (TSP-C).

n... su.h basket will be le.atcd withit containment recirculation sump.

oconfincS of cAch contanmont rocirculation sump. The baskets contain sufficient TSP-C to ensure a minimum equilibrium sump pH of 7.1. Gae scismically dcsignod TSP C baskct is within thc confinoc of each of the two contai.nm.nt rocirc-uation cump&. Each basket is designed to contain a maximu of 6720 Ibmn of TSP C (basis for the moximum dcpth of 36.8" n tho. T-cRhnical Spccification) Whrcoac a inimm depth of. 3!,

c....s.n.in.

to 1500

.Must

-he containcd in o h-;

b %-YY_*o ensure an equilibrium sump pH of at least 7.1. The baskets are located at an elevation that will ensure dissolution by the sump fluids. The baskets have a stainless steel frame with walls constructed of stainless steel grating and lined with #100 wire mesh stainless steel screening. Inside nominal dimensions of each basket is 80" x 56" x 38". The calculation of the minimum and maximum depths of TSP-C includes conservative allowances for compaction, Gpillagc throuigh the Wirc moesh, density variations, and the limited transformation of TSP-C into disodium triphosphate which is a weaker base (expected to have a small impact in the outer surface layer). The minimum equilibrium sump pH of 7.1 corresponds to a minimum o2iFO Ibm of TSP-C in the baskets and a maximum sump boron concentration of 2500 ppm. If the maximum of I3T 13,4,4,0 Ibm of TSP-C were contained in the baskets at the end of cycle UPlfo.uc that a minimu m sump b..or conccntration of 2007 ppm would eeeiH, the maximum equilibrium sump pH would be less than 8.1.

CALLAWAY PLANT B 3.6.7-1 (continued)

Revision 1

Insert 1 a maximum of 7150 Ibm of TSP-C (basis for the maximum depth of 36.8 " of TSP-C in each basket) whereas a minimum depth of 30", corresponding to 4500 Ibm, must be contained in each basket

Aý

ý -ý Recirculation Fluid pH Control System B 3.6.7 BASES ACTIONS A.1 (continued) atmosphere in the event of a DBA. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time takes into account the redundant flow path capabilities and the low probability of the worst case DBA occurring during this period.

B.1 and B.2 If the RFPC System cannot be restored to OPERABLE status within the required Completion Time, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and to MODE 5 within 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br />. The allowed Completion Time of 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> is reasonable, based on operating experience, to reach MODE 3 from full power conditions in an orderly manner and without challenging plant systems. The extended interval to reach MODE 5 allows additional time for attempting restoration of the RFPC System and is reasonable when considering the driving force for the release of radioactive material from the Reactor Coolant System is reduced in MODE 3.

SURVEILLANCE SR 3.6.7.1 REQUIREMENTS d

This SR verifies tat the TSP-C baskets are in place in each contaminant reirc'*lctienesumpI there is no evidence of structural distress or abnormal insert Blank Line

) corrosion, and thcro is ;ufficiont TSP C available in the RFPC system.

The 18 month Frequency is based on entry into the sumpor routine containment reiuelin outaes-* iRG t.... and GR the low probability of -;;A lcvcl occurr.ing du*rg the SR....o.....

l_' a reduction in TSP-C basket integrity FIInsert Bases SR 3.6.7.2 I

a" I during the SR interval REFERENCES

1.

FSAR, Chapter 6.5, and 6.2.2.

CALLAWAY PLANT B 3.6.7-3 Revision 1

a~

• Ž-

SR 3.6.7.2 Bases Insert SR 3.6.7.2 Periodic determination of the amount of TSP-C in containment must be performed due to the possibility of leaking valves and components in the containment building that could cause dissolution of the TSP-C during normal operation. This SR determines visually, by TSP-C level in each basket, that a minimum total amount of 9000 pounds of TSP-C is contained in the storage baskets and that the maximum amount of TSP-C in each basket does not exceed the structural integrity. Meeting this SR ensures that there is an adequate amount of TSP-C to adjust the pH of the post LOCA sump solution to a value >_ 7.1.

The 18 month Frequency is based on entry into the containment for routine refueling outages and on the low probability of an undetected change in basket level. Operating experience has shown this surveillance frequency acceptable due to the margin in the volume of TSP placed in the containment building.