13 Defueling Filter Test
Downloaded by EAST CAROLINA UNIV on January 3, 2018 | http://pubs.acs.org Publication Date: December 23, 1986 | doi: 10.1021/bk-1986-0293.ch013
J. M . Storton and J. F. Kramer Research & Development Division, Babcock & Wilcox, Lynchburg, VA 24506-1165
The Three Mile Island Unit 2 Reactor (TMI-2) has sustained core damage creating a significant quantity of fine debris, which can become suspended during the planned defueling operations, and will have to be constantly removed to maintain water clarity and minimize radiation exposure. To accomplish these objectives, a Defueling Water Cleanup System (DWCS) has been designed. One of the primary components in the DWCS is a custom designed filter canister using an all stainless steel filter medium. The full scale filter canister is designed to remove suspended solids from 800 microns to 0.5 microns in size. Filter cartridges are fabricated into an element cluster to provide for a flowrate of greater than 100 gals/min. Babcock & Wilcox (B&W) under contract to GPU Nuclear Corporation has evaluated two candidate DWCS filter concepts in a 1/100 scale proof-of-principle test program at B&W's Lynchburg Research Center. The filters were challenged with simulated solids suspensions of 1400 and 140 ppm in borated water (5000 ppm boron). Test data collected includes solids loading, effluent turbidity, and differential pressure trends versus time. From the proof-of-principle test results, a full-scale filter canister was generated. The Three Mile Island Unit 2 Reactor (TMI-2) Recovery Operation p r e s e n t s a s i g n i f i c a n t challenge to the n u c l e a r i n d u s t r y . An important aspect i n the TMI-2 Recovery e f f o r t i s the water treatment techniques used to maintain water c l a r i t y and control radiation l e v e l s during the defueling operation. The d e f u e l i n g o p e r a t i o n at TMI-2 r e q u i r e s that high water quality be maintained. This i s necessary to ensure adequate water quality f o r d i r e c t viewing of the defueling operations and to provide that radiation dose rates to workers from suspended s o l i d s are as low as reasonably achievable (ALARA). In an undamaged reactor suspended corrosion products can cause a v i s i b i l i t y problem. The TMI-2 reactor sustained damage creating a s i g n i f i c a n t quantity of 0097-6156/ 86/0293-0239S06.00/0 © 1986 American Chemical Society
Toth et al.; The Three Mile Island Accident ACS Symposium Series; American Chemical Society: Washington, DC, 1986.
THE THREE MILE ISLAND ACCIDENT
Downloaded by EAST CAROLINA UNIV on January 3, 2018 | http://pubs.acs.org Publication Date: December 23, 1986 | doi: 10.1021/bk-1986-0293.ch013
240
f i n e debris which can become suspended when disturbed during the defueling a c t i v i t i e s . Therefore, maintaining the water c l a r i t y within the TMI-2 reactor i s a challenging engineering problem. Two objectives of adequate water c l a r i t y and reduced worker dose rates can be maintained i f the t u r b i d i t y of the borated water i s α
tn
m H χ m
247 13.
Defueling Filter Test
STORTON AND KRAMER
Table I I .
S o l i d Fines Test Materials
Zirconium Dioxide Zirox-70 Zirox-250 Iron Oxide F e 0 (red) Uranium Oxide uo 2
3
9
Downloaded by EAST CAROLINA UNIV on January 3, 2018 | http://pubs.acs.org Publication Date: December 23, 1986 | doi: 10.1021/bk-1986-0293.ch013
L
Stainless
Steel 316L powder
95% 40% 95% 40%
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