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Title: PWR upper/lower internals shield

Conference ·
OSTI ID:54657
 [1]
  1. Indian Point Station, Buchanan, NY (United States)

During refueling of a nuclear power plant, the reactor upper internals must be removed from the reactor vessel to permit transfer of the fuel. The upper internals are stored in the flooded reactor cavity. Refueling personnel working in containment at a number of nuclear stations typically receive radiation exposure from a portion of the highly contaminated upper intervals package which extends above the normal water level of the refueling pool. This same issue exists with reactor lower internals withdrawn for inservice inspection activities. One solution to this problem is to provide adequate shielding of the unimmersed portion. The use of lead sheets or blankets for shielding of the protruding components would be time consuming and require more effort for installation since the shielding mass would need to be transported to a support structure over the refueling pool. A preferable approach is to use the existing shielding mass of the refueling pool water. A method of shielding was devised which would use a vacuum pump to draw refueling pool water into an inverted canister suspended over the upper internals to provide shielding from the normally exposed components. During the Spring 1993 refueling of Indian Point 2 (IP2), a prototype shield device was demonstrated. This shield consists of a cylindrical tank open at the bottom that is suspended over the refueling pool with I-beams. The lower lip of the tank is two feet below normal pool level. After installation, the air width of the natural shielding provided by the existing pool water. This paper describes the design, development, testing and demonstration of the prototype device.

Research Organization:
US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Div. of Regulatory Applications; Brookhaven National Lab. (BNL), Upton, NY (United States)
OSTI ID:
54657
Report Number(s):
NUREG/CP-0143; BNL-NUREG-52440; CONF-940505-; ON: TI95008770; TRN: 95:012691
Resource Relation:
Conference: 3. international workshop on implementation of ALARA at nuclear power plants, Long Island, NY (United States), 8-11 May 1994; Other Information: PBD: Mar 1995; Related Information: Is Part Of Proceedings of the Third International Workshop on the implementation of ALARA at nuclear power plants; Khan, T.A. [comp.] [Brookhaven National Lab., Upton, NY (United States)]; Roecklein, A.K. [Nuclear Regulatory Commission, Washington, DC (United States). Div of Regulatory Applications]; PB: 810 p.
Country of Publication:
United States
Language:
English