Demonstration of Passive Phoretic Decontamination by Accident Simulation in a Scaled Reactor Containment

Journal Article · Sat Jul 01 04:00:00 EDT 2017 · Transactions of the American Nuclear Society

OSTI ID:23050249

Talabi, Sola ^[1]

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1. Pittsburgh Technical, 9687 Babcock Blvd. Allison Park PA. 15101 (United States)

Reactor containment performance is a critical defense-in- depth barrier for the prevention of radioactive release in the event of a nuclear accident. One of the functions of the containment is to assist in the decontamination of aerosolized radioactive particles through both 'passive' or natural processes and 'active' or mechanical processes. Current United States Nuclear Regulatory Commission (NRC) guidance (Reg. guide 1.183) allows the use of aerosol natural deposition correlations to quantify postaccident nuclear containment decontamination factors. Large Light Water Reactor (LLWR) correlations have previously been developed to quantify the contribution of natural phenomena to post-accident aerosol decontamination. Specific correlations must similarly be developed to support the safety analyses of Small Modular Reactors (SMRs). For LLWR plants, decontamination is achieved 'actively' by mechanical systems such as containment sprays and 'passively' via natural phenomena such as gravitational settling, condensation, impaction, thermophoresis, diffusiophoresis and hygroscopic effects. Integrated pressurized water reactor (iPWR) SMR designs do not have containment sprays; therefore, they rely primarily on passive natural phenomena for decontamination in the integrated reactor vessel. Analytical studies and inferences from LLWR test data suggest that the smaller containment vessel volume to surface area ratio, coupled with the thermal hydraulic properties of iPWR plants, would significantly enhance decontamination factors for these smaller designs. The research aims to quantify the amount of decontamination from natural phenomena for the range of iPWR physical and thermal hydraulic characteristics. A preliminary assessment has shown that diffusiophoresis, thermophoresis and hygroscopic effects are the major areas with a research gap for iPWR plants; hence these areas are the foci of the research. These first-of-a-kind experiments will be described and preliminary analytical results will be presented that show the expected effects of SMR-specific correlations on passive decontamination of aerosolized radionuclides.

• OSTI ID: 23050249
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 116; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
AEROSOLS
CONTAINMENT BUILDINGS
DECONTAMINATION
EFFICIENCY
PERFORMANCE
PWR TYPE REACTORS
RADIATION ACCIDENTS
RADIOISOTOPES
REACTOR ACCIDENT SIMULATION
REACTOR ACCIDENTS
REACTOR VESSELS
SAFETY ANALYSIS
SMALL MODULAR REACTORS
SPRAYS
SURFACE AREA
THERMAL HYDRAULICS
THERMOPHORESIS