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Title: Thermal insulating barrier and neutron shield providing integrated protection for a nuclear reactor vessel

The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel to form a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive valving also includes bistable vents at the upper end of the thermal insulating barrier for releasing steam. A removable, modular neutron shield extending around the upper end of the reactor cavity below the nozzles forms with the upwardly and outwardly tapered transition on the outer surface of the reactor vessel, a labyrinthine channel which reduces neutron streaming while providing a passage for the escape of steam during a severe accident, and for the cooling air which is circulated along the reactor cavity walls outside the thermal insulating barrier during normal operation of the reactor.
 [1];  [2];  [3]
  1. (Penn Twp., PA)
  2. (New Kensington, PA)
  3. (Murrysville, PA)
Issue Date:
OSTI Identifier:
Westinghouse Electric Corporation (Pittsburgh, PA) OAK
Patent Number(s):
US 5699394
Contract Number:
Research Org:
Westinghouse Electric Corp
Country of Publication:
United States
thermal; insulating; barrier; neutron; shield; providing; integrated; protection; nuclear; reactor; vessel; installation; suspended; cold; leg; nozzles; cavity; provided; spaced; form; chamber; flooded; cooling; water; passive; valving; directly; cool; event; severe; accident; bistable; vents; upper; releasing; steam; removable; modular; extending; below; forms; upwardly; outwardly; tapered; transition; outer; surface; labyrinthine; channel; reduces; streaming; passage; escape; air; circulated; walls; outside; normal; operation; neutron shield; reactor cavity; cooling air; cooling water; normal operation; reactor vessel; nuclear reactor; outer surface; thermal insulating; cavity walls; cavity wall; cold leg; reactor installation; /376/