ML052090185
| ML052090185 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 07/29/2005 |
| From: | Hopkins J NRC/NRR/DLPM/LPD3 |
| To: | Crane C Exelon Generation Co |
| Hopkins J , NRR/DLPM, 301-415-3027 | |
| References | |
| TAC MC6221, TAC MC6222, TAC MC6223, TAC MC6224 | |
| Download: ML052090185 (7) | |
Text
July 29, 2005 Mr. Christopher M. Crane, President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
BRAIDWOOD UNITS 1 AND 2, AND BYRON UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION (TAC NOS. MC6221, MC6222, MC6223, AND MC6224)
Dear Mr. Crane:
By letter dated February 15, 2005, you submitted a license amendment request for an alternative radiological source term for Braidwood Units 1 and 2, and Byron Units 1 and 2. The U.S. Nuclear Regulatory Commission (NRC) has been reviewing your request and finds that we need additional information to complete our review. These questions are from one technical branch. Additional questions are expected from the other technical review branches.
The enclosed questions were forwarded to your staff by facsimile on June 17, 2005. Based on communication with your staff, we have determined that question A.2 does not need to be answered as your submittal provides sufficient information. Your staff has also agreed to respond to these questions 120 days from the date of this letter.
Contact me if you have any questions.
Sincerely,
/RA/
Jon B. Hopkins, Senior Project Manager, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. STN 50-454, STN 50-455, STN 50-456 and STN 50-457
Enclosure:
As stated cc w/encl: See next page
ML052090185 Nrr-088 OFFICE PM:LPD3-2 LA:LPD3-2 SC:LPD3-2 NAME JHopkins PCoates GSuh DATE 7-29-05 7/28/05 7-29-05 Byron/Braidwood Stations cc:
Dwain W. Alexander, Project Manager Westinghouse Electric Corporation Energy Systems Business Unit Post Office Box 355 Pittsburgh, PA 15230-0355 Joseph Gallo Gallo & Ross 1025 Connecticut Ave., NW, Suite 1014 Washington, DC 20036 Howard A. Learner Environmental Law and Policy Center of the Midwest 35 East Wacker Dr., Suite 1300 Chicago, IL 60601-2110 U.S. Nuclear Regulatory Commission Byron Resident Inspectors Office 4448 N. German Church Road Byron, IL 61010-9750 Regional Administrator, Region III U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, IL 60532-4351 Ms. Lorraine Creek RR 1, Box 182 Manteno, IL 60950 Chairman, Ogle County Board Post Office Box 357 Oregon, IL 61061 Mrs. Phillip B. Johnson 1907 Stratford Lane Rockford, IL 61107 George L. Edgar Morgan, Lewis and Bockius 1800 M Street, NW Washington, DC 20036-5869 Attorney General 500 S. Second Street Springfield, IL 62701 Illinois Emergency Management Agency Division of Disaster Assistance &
Preparedness 110 East Adams Street Springfield, IL 62701-1109 Byron Station Plant Manager Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Site Vice President - Byron Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 U.S. Nuclear Regulatory Commission Braidwood Resident Inspectors Office 35100 S. Rt. 53, Suite 79 Braceville, IL 60407 County Executive Will County Office Building 302 N. Chicago Street Joliet, IL 60432 Braidwood Station Plant Manager Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Ms. Bridget Little Rorem Appleseed Coordinator 117 N. Linden Street Essex, IL 60935
Byron/Braidwood Stations Document Control Desk - Licensing Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Site Vice President - Braidwood Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Senior Vice President - Nuclear Services Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Vice President of Operations - Mid-West Pressurized Water Reactors Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Regulatory Assurance Manager - Braidwood Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Regulatory Assurance Manager - Byron Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Associate General Counsel Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Vice President - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Manager Licensing - Braidwood, Byron and LaSalle Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Mr. Barry Quigley 3512 Louisiana Rockford, IL 61108
ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION EXELON GENERATION COMPANY, LLC ALTERNATIVE RADIOLOGICAL SOURCE TERM BRAIDWOOD UNITS 1 AND 2, AND BYRON UNITS 1 AND 2 DOCKET NOS. STN 50-456, STN 50-457, STN 50-454, AND STN 50-455 A. Iodine Leakage After a loss-of-coolant accident (LOCA), a significant portion of the inventory of core iodine is released to the containment and some of this iodine leaks to the outside. In the submittal, two release paths are identified: containment leakage and emergency core cooling systems (ECCS) leakage.
Containment Leakage Path (1)
The iodine from the damaged core is released to the containment as 95% CsI and 5 %
as I2 and HI. CsI and HI are soluble in sump water but I2 is scarcely soluble. If the sump water is acidic some of the ionic iodine from CsI is converted to I2 and because of its low solubility it is released into containment atmosphere and some of it will leak to the outside. To prevent this from happening the pH of the sump water has to be maintained at the pH value of $7. Describe your program for controlling sump pH to maintain it basic. The description should include: (a) chemicals used for sump pH control; (b) the procedure and the corresponding calculations for determining the amount of chemicals needed for neutralizing the effect of acidic chemicals in the containment such as boric, hydrochloric or nitric acids.
ECCS Recirculation Leakage Path (2)
Provide the basis for assuming the value of 276,000 cc/hr for the ECCS recirculation leakage rate used in the AST LOCA analysis. (NO ANSWER REQUIRED.)
(3)
In the ECCS leakage path leading to the Borated Water Storage Tank (BWST), the sump water will mix with the remaining borated water in the tank. Since the BWST water contains between 2300 and 2500 ppm of boron in form of boric acid, the pH of the mixture of sump and BWST water will have lower pH (most probably well below 7).
Lowering the pH of the sump water will cause the conversion of ionic iodine into the elemental form and its corresponding release to the reactor water storage tank (RWST) air space. This effect will increase the total release of radioactive iodine from engineering safety features and cause correspondingly higher radiation doses.
Was this effect included in the licensees analysis? If it was included, provide its description and the analyses for determining its significance to the overall release of radioactivity in the ECCS recirculation leakage path.
B. Iodine Removal (4)
Provide the reason why natural deposition of elemental iodine was not considered in your analysis.