United States Patent m
 APPARATUS AND METHOD FOR
CHEMICALLY DECONTAMIN ATING A
PWR REACTOR COOLANT SYSTEM
 Inventor: William J. Stenger, Penn Township, Westmoreland County, Pa.
 Assignee: Westinghouse Electric Corp., Pittsburgh, Pa.
 Appl. No.: 999,343
 Filed: Dec. 31,1992
 Int. C1.5 G21C 9/00
 UJS. CI 376/305; 376/310;
 Field of Search 376/305, 306, 310, 313
 References Cited
U.S. PATENT DOCUMENTS
3,783,268 1/1974 Neeb et al 250/83.3 R
4,684,494 8/1987 Dagard 376/313
4,699,755 10/1987 Dagard et al 376/313
4,842,812 6/1989 Panson et al 376/306
5,082,618 1/1992 Dagard 376/219
Primary Examiner—Donald P. Walsh
[ii] Patent Number: 5,377,244  Date of Patent: Dec. 27,1994
Assistant Examiner—Frederick H. Voss
The reactor coolant system (RCS) of a pressurized water reactor (PWR) is chemically decontaminated and cleaned utilizing apparatus which is comprised of components designed to operate at low pressures while still utilizing installed reactor coolant pumps and/or the residual heat removal pumps to generate the high flow rates required for the process. A high volume diverted flow of reactor coolant from the RCS is passed through letdown valves to reduce the high pressure produced by the installed pumps. Chemical decontamination and cleaning agents are mixed with the low pressure diverted flow and returned to the RCS by high head injection pumps. Contamination solubilized by the decontamination and cleaning agents is removed as the reactor coolant is recirculated through demineralizers. Filters remove particulates, and fines from the demineralizer resins. A surge tank, which may or preferably is not, in the path of the diverted flow provides reactor coolant for backwashing the demineralizers and filters and downloading the demineralizer resins.
14 Claims, 3 Drawing Sheets