ML072670549

Request for Additional Information Regarding Proposed Ph Control System Buffer Change

ML072670549
Person / Time
Site:	Three Mile Island
Issue date:	10/04/2007
From:	Peter Bamford NRC/NRR/ADRO/DORL/LPLI-2
To:	Crane C AmerGen Energy Co
Bamford, Peter J., NRR/DORL 415-2833
References
TAC MD5963
Download: ML072670549 (6)

Text

October 4, 2007 Mr. Christopher M. Crane President and Chief Executive Officer AmerGen Energy Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348

SUBJECT:

THREE MILE ISLAND NUCLEAR STATION, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED REACTOR BUILDING EMERGENCY SUMP SYSTEM BUFFER CHANGE (TAC NO. MD5963)

Dear Mr. Crane:

By letter dated June 29, 2007 (Agencywide Documents Access and Management System Accession Number ML072070257), AmerGen Energy Company, LLC, submitted an amendment request for the Three Mile Island Nuclear Station, Unit 1. The proposed amendment would revise the technical specifications to accommodate a change in the reactor building emergency sump pH control system buffer from sodium hydroxide to trisodium phosphate dodecahydrate.

The NRC staff has been reviewing the submittal and has determined that additional information is needed to complete its review. The specific questions are found in the enclosed request for additional information. The questions were sent via electronic transmission on September 18 and September 24, 2007, to Mr. David Distel of your staff. The draft questions were sent to ensure that the questions were understandable, the regulatory basis for the questions was clear, and to determine if the information was previously docketed. The majority of these questions were discussed with your staff in a teleconference on September 20, 2007, where clarification was provided in some areas and one of the draft questions was deleted. It was agreed that your response would be provided within 30 days of the date of this letter.

Please contact me at 301-415-2833, if you have any questions.

Sincerely,

/RA /

Peter J. Bamford, Project Manager Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-289

Enclosure:

As stated cc w/encl: See next page

Mr. Christopher M. Crane President and Chief Executive Officer AmerGen Energy Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348

SUBJECT:

THREE MILE ISLAND NUCLEAR STATION, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED REACTOR BUILDING EMERGENCY SUMP SYSTEM BUFFER CHANGE (TAC NO. MD5963)

Dear Mr. Crane:

By letter dated June 29, 2007 (Agencywide Documents Access and Management System Accession Number ML072070257), AmerGen Energy Company, LLC, submitted an amendment request for the Three Mile Island Nuclear Station, Unit 1. The proposed amendment would revise the technical specifications to accommodate a change in the reactor building emergency sump pH control system buffer from sodium hydroxide to trisodium phosphate dodecahydrate.

The NRC staff has been reviewing the submittal and has determined that additional information is needed to complete its review. The specific questions are found in the enclosed request for additional information. The questions were sent via electronic transmission on September 18 and September 24, 2007, to Mr. David Distel of your staff. The draft questions were sent to ensure that the questions were understandable, the regulatory basis for the questions was clear, and to determine if the information was previously docketed. The majority of these questions were discussed with your staff in a teleconference on September 20, 2007, where clarification was provided in some areas and one of the draft questions was deleted. It was agreed that your response would be provided within 30 days of the date of this letter.

Please contact me at 301-415-2833, if you have any questions.

Sincerely,

/RA/

Peter J. Bamford, Project Manager Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-289

Enclosure:

As stated cc w/encl: See next page DISTRIBUTION:

PUBLIC RidsOgcRp LPLI-2 R/F RidsAcrsAcnwMailCenter RidsNrrPMPBamford RidsNrrLACSola RidsRgn1MailCenter RidsNrrDorlDpr RidsNrrDorlLpl1-2 RidsNrrLAABaxter MYoder, NRR KParczewski, NRR NPatel, NRR ADAMS Accession Number: ML072670549

• by memo OFFICE LPL1-2/PM LPL1-2/LA LPL2-2/LA EEEB/BC* CSGB/BC* LPL1-2/BC NAME PBamford ABaxter CSola GWilson AHiser HChernoff DATE 9/25/07 10/1/07 9/28/07 09/20/2007 09/17/2007 10/4/07 OFFICIAL RECORD COPY

Three Mile Island Nuclear Station, Unit 1 cc:

Site Vice President - Three Mile Island Nuclear Director Station, Unit 1 Bureau of Radiation Protection AmerGen Energy Company, LLC Pennsylvania Department of P. O. Box 480 Environmental Protection Middletown, PA 17057 Rachel Carson State Office Building P.O. Box 8469 Vice President - Operations, Mid-Atlantic Harrisburg, PA 17105-8469 AmerGen Energy Company, LLC 200 Exelon Way, KSA 3-N Plant Manager - Three Mile Island Nuclear Kennett Square, PA 19348 Station, Unit 1 AmerGen Energy Company, LLC Vice President - Licensing and Regulatory P. O. Box 480 Affairs Middletown, PA 17057 AmerGen Energy Company, LLC 4300 Winfield Road Regulatory Assurance Manager - Three Mile Warrenville, IL 60555 Island Nuclear Station, Unit 1 AmerGen Energy Company, LLC Regional Administrator P.O. Box 480 Region I Middletown, PA 17057 U.S. Nuclear Regulatory Commission 475 Allendale Road Ronald Bellamy, Region I King of Prussia, PA 19406 U.S. Nuclear Regulatory Commission 475 Allendale Road Chairman King of Prussia, PA 19406 Board of County Commissioners of Dauphin County Michael A. Schoppman Dauphin County Courthouse Framatome ANP Harrisburg, PA 17120 Suite 705 1911 North Ft. Myer Drive Chairman Rosslyn, VA 22209 Board of Supervisors of Londonderry Township Dr. Judith Johnsrud R.D. #1, Geyers Church Road National Energy Committee Middletown, PA 17057 Sierra Club 433 Orlando Avenue Senior Resident Inspector (TMI-1) State College, PA 16803 U.S. Nuclear Regulatory Commission P.O. Box 219 Eric Epstein Middletown, PA 17057 TMI Alert 4100 Hillsdale Road Director - Licensing and Regulatory Affairs Harrisburg, PA 17112 AmerGen Energy Company, LLC 200 Exelon Way, KSA 3-E Correspondence Control Desk Kennett Square, PA 19348 AmerGen Energy Company, LLC P.O. Box 160 Kennett Square, PA 19348

Three Mile Island Nuclear Station, Unit 1 cc:

Manager Licensing - Three Mile Island Nuclear Station, Unit 1 Exelon Generation Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348 Mr. Christopher M. Crane President and Chief Executive Officer AmerGen Energy Company, LLC 4300 Winfield Road Warrenville, IL 60555 Assistant General Counsel AmerGen Energy Company, LLC 200 Exelon Way Kennett Square, PA 19348

REQUEST FOR ADDITIONAL INFORMATION REGARDING REACTOR BUILDING EMERGENCY SUMP SYSTEM BUFFER CHANGE THREE MILE ISLAND NUCLEAR STATION, UNIT 1 TAC NO. MD5963 DOCKET NO. 50-289 By letter dated June 29, 2007, (Agencywide Documents Access and Management System Accession No. ML072070257), AmerGen Energy Company, LLC, the licensee, submitted a license amendment request pertaining to the replacement of the containment sump buffer at Three Mile Island Nuclear Station, Unit 1 (TMI-1).

The Nuclear Regulatory Commission (NRC) Staff has been reviewing the submittal and has determined that additional information is needed to complete its review.

1. In Section 7.1, page 15 of Attachment 2, the licensee listed eight chemicals which will exist in the sump water after a loss of coolant accident (LOCA). In its analysis, the licensee assumed that each of them will dissociate or speciate into positive or negative ionic species. By balancing the resulting positive and negative charges, to obtain neutrality of the solution, the licensee could determine the amount of trisodium phosphate (TSP) required for obtaining a given value of pH. Provide a list of the ionic species.

2. Describe the procedure for determining speciation of boron and TSP.

3. Explain the statement in Section 2.6 on page 5 of Attachment 2 that boron content will not be exceeded provided the power rate does not increase (2568 MWt) and the cycle duration (2 years) does not increase.

4. In Section 6, on page 13 of Attachment 2, it is stated that water and boric acid in the sump is determined from a mass balance with two bounding conditions for water and boric acid.

What are they and how were they determined?

5. According to Regulatory Guide 1.183, if the sump pH is controlled at the minimum values of 7, the molecular iodine is prevented from formation and release to the containment.

However, during the engineered safety feature recirculation phase, a higher pH is assumed to support iodine flashing fractions at 5 percent for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and 2 percent for the following 29 days. In the submittal the licensee specified the required pH

7.3. Discuss

(1) the methodology for determining this pH value and (2) was the sump water pH buffered at this pH?

Enclosure

6. Proposed insert C to technical specification (TS) page 4-2b describes the need to perform periodic solubility tests on the TSP to ensure adequate dissolution time. However, insert D to the proposed TS surveillance requirements, TS page 4-10c, does not include solubility as one of the verifications performed on the TSP. Describe this apparent discrepancy between the TS bases and the TS surveillance requirement.

7. When verifying the TSP buffering capability, solubility, and total mass, how is the sample obtained? How does the sampling account for the potential that the TSP on the interior of the basket may exhibit different properties (hydration, density, etc.) than samples taken from the basket periphery? Discuss the potential impact that variations in material properties within each basket may have on surveillance tests to determine buffer capability, solubility, and total mass of TSP available.

8. Proposed insert C to TS page 4-2b describes the need to periodically determine the mass of TSP because leaking valves and components may dissolve some of the TSP from the baskets. If a leaking valve or component were to result in a portion of the TSP being dissolved, how would the dissolved TSP be accounted for when adding additional TSP to the basket. If there is no mechanism for removing the dissolved TSP then addition of more TSP may result in a total mass that exceeds the TS limits. Discuss how the loss of TSP through operational dissolution is accounted for when determining the total mass of TSP.

9. TMI-1 is proposing to switch to TSP as a buffering chemical. Testing indicates that TSP in the presence of dissolved calcium can result in rapid precipitation of calcium phosphate, which can create significant head loss across a sump strainer covered with a debris bed.

Provide a list of all potential sources and amounts of calcium within the TMI-1 containment and provide the calculated dissolved calcium concentration in a post-LOCA pool. Provide the relative chemical precipitate loading predicted by the WCAP 16530-NP, [Evaluation of Post-Accident Chemical Effects in Containment Sump Fluids to Support GSI-191], model for TMI-1 with TSP and at the maximum projected pH value (8) for the pool.

10. In Section 4.5 of Enclosure 1 to the proposed license amendment request, it is stated that the evaluation was based on utilizing and analyzing available industry and technical research data. The evaluation concluded that all environmentally qualified equipment located inside the Reactor Building (RB) are qualified for the revised RB spray chemical conditions resulting from the proposed change. Please provide details of the methodology, assumptions, regulatory provisions applied and analysis to support the above conclusion.

11. Please confirm that the temperature profile inside the RB remains unchanged due to the proposed design change.