Systems and methods for enhancing isolation of high-temperature reactor containments

Patent metadata

Field	Value
Publication number	US-9773574-B2
Application number	US-201414533055-A
Country	US
Kind code	B2
Filing date	Nov 4, 2014
Priority date	Nov 4, 2013
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

A high-temperature containment-isolation system for transferring heat from a nuclear reactor containment to a high-pressure heat exchanger is presented. The system uses a high-temperature, low-volatility liquid coolant such as a molten salt or a liquid metal, where the coolant flow path provides liquid free surfaces a short distance from the containment penetrations for the reactor hot-leg and the cold-leg, where these liquid free surfaces have a cover gas maintained at a nearly constant pressure and thus prevent high-pressures from being transmitted into the reactor containment, and where the reactor vessel is suspended within a reactor cavity with a plurality of refractory insulator blocks disposed between an actively cooled inner cavity liner and the reactor vessel.

First claim

What is claimed is:

1. A high temperature reactor (HTR) cooled by a low-volatility, liquid coolant, comprising:
a reactor cavity having an inner cavity liner; and
a reactor vessel disposed within the reactor cavity;
wherein the reactor vessel is suspended within the reactor cavity with a plurality of refractory insulator blocks disposed between the inner cavity liner and the reactor vessel;
wherein the plurality of refractory insulator blocks are separated by gaps;
wherein the gaps between the plurality of refractory insulator blocks act to provide flow paths for natural circulation of low-volatility liquid coolant to thereby remove heat from the reactor vessel in the event of a reactor vessel coolant leak;
wherein the plurality of refractory insulator blocks are chemically compatible and impermeable to the low-volatility liquid coolant in the event of coolant leaking from the reactor vessel.

2. An HTR as recited in claim 1 :
wherein the reactor vessel is suspended in the reactor cavity via a conical support ring having a first end coupled to the inner cavity liner and a second end coupled to the reactor vessel; and
wherein the conical support ring accommodates temperature differentials between the reactor vessel and reactor cavity.

3. An HTR as recited in claim 2 :
wherein the second end of the conical support ring attaches to the reactor vessel via a conical joint; and
wherein the conical joint is configured to allow for differential thermal expansion or horizontal loading within the reactor vessel.

4. An HTR as recited in claim 1 , further comprising:
an annular thermal expansion gap formed between the plurality of refractory insulator blocks and the reactor vessel.

5. An HTR as recited in claim 1 , wherein the inner cavity liner comprises an actively cooled steel liner plate.

6. An HTR as recited in claim 4 , further comprising:
a plurality of slots disposed within an internal surface of the refractory blocks adjacent said annular thermal expansion gap; and
a plurality of electric heating rods disposed within the plurality of slots, the electric heating rods running substantially along the length of the reactor vessel.

7. An HTR as recited in claim 1 , the reactor cavity having an outer containment wall, the HTR further comprising:
a hot-leg pipe coupled to the reactor vessel at a penetration of the outer containment wall;
wherein the hot-leg pipe provides a coolant flow path from the reactor vessel through the outer containment wall to a location external to the reactor vessel; and
wherein the hot-leg penetration is insulated and has a flexible bellows seal.

8. An HTR as recited in claim 7 , further comprising:
an isolation valve and a hot-well vessel coupled to the hot leg;
wherein hot coolant exiting the reactor vessel flows through the isolation valve into the hot-well vessel.

9. An HTR as recited in claim 8 , wherein the hot-well vessel provides a substantial liquid free surface, the hot-well vessel further comprising:
a centrifugal pump submerged in the hot well and configured to circulate the hot coolant into a crossover-leg to a high-pressure heat exchanger; and
wherein the liquid free surface has a cover gas maintained at a nearly constant pressure and thus prevents high-pressures from being transmitted into the reactor vessel.

10. An HTR as recited in claim 1 , the reactor cavity having an outer containment wall, the HTR further comprising:
a cold-leg pipe coupled to the reactor vessel at a penetration of the outer containment wall;
wherein the cold-leg pipe provides a coolant flow path into the reactor vessel through the outer containment wall from a main-salt loop external to the reactor vessel; and
wherein the cold-leg penetration is insulated and has a flexible bellows seal.

11. An HTR as recited in claim 10 , further comprising:
a standpipe coupled to the cold-leg pipe;
wherein the standpipe provides a substantial liquid free surface; and
wherein the liquid free surface has a cover gas maintained at a nearly constant pressure and thus prevents high-pressures from being transmitted into the reactor vessel.

12. An HTR as recited in claim 1 , wherein the refractory insulator blocks comprise a reduced permeability surface to restrict absorption of the low-volatility liquid coolant.

13. An HTR as recited in claim 12 , wherein the refractory insulator blocks coated with a glazing material to reduce the permeability of the surface.

14. An HTR as recited in claim 12 , wherein the refractory insulator blocks comprise a porosity configured to reduce the permeability of the surface.

15. An HTR as recited in claim 1 , wherein the refractory insulator blocks are positioned in the reactor cavity so as to minimize the free volume of the reactor cavity and corresponding leakage of the low-volatility liquid coolant in the event of a reactor vessel coolant leak.

16. A high temperature reactor (HTR) cooled by a low-volatility, liquid coolant, comprising:
a reactor cavity having an inner cavity liner; and
a reactor vessel disposed within the reactor cavity;
wherein the reactor vessel is suspended within the reactor cavity with a plurality of refractory insulator blocks disposed between the inner cavity liner and the reactor vessel;
wherein the reactor cavity comprises an outer containment wall,
a hot-leg pipe coupled to the reactor vessel at a penetration of the outer containment wall;
wherein the hot-leg pipe provides a coolant flow path from the reactor vessel through the outer containment wall to a location external to the reactor vessel; and
wherein the hot-leg penetration is insulated and has a flexible bellows seal;
an isolation valve and a hot-well vessel coupled to the hot leg;
wherein hot coolant exiting the reactor vessel flows through the isolation valve into the hot-well vessel;
wherein the hot-well vessel provides a substantial liquid free surface, and a centrifugal pump submerged in the hot well and configured to circulate the hot coolant into a crossover-leg to a high-pressure heat exchanger; and
wherein the liquid free surface has a cover gas maintained at a nearly constant pressure and thus prevents high-pressures from being transmitted into the reactor vessel.

17. A high temperature reactor (HTR) cooled by a low-volatility, liquid coolant, comprising:
a reactor cavity having an inner cavity liner; and
a reactor vessel disposed within the reactor cavity;
wherein the reactor vessel is suspended within the reactor cavity with a plurality of refractory insulator blocks disposed between the inner cavity liner and the reactor vessel;
wherein the reactor cavity comprises an outer containment wall;
a cold-leg pipe coupled to the reactor vessel at a penetration of the outer containment wall;
wherein the cold-leg pipe provides a coolant flow path into the reactor vessel through the outer containment wall from a main-salt loop external to the reactor vessel; and
wherein the cold-leg penetration is insulated and has a flexible bellows seal; and
a standpipe coupled to the cold-leg pipe;
wherein the standpipe provides a substantial liquid free surface; and
wherein the liquid free surface has a cover gas maintained at a nearly constant pressure and thus prevents high-pressures from being transmitted into the reactor vessel.

Assignees

• Univ California

Inventors

• Peterson Per F

Classifications

• Y02E30/35

  Cross-Sectional Technologies · mapped topic

• G21C15/18

  Emergency cooling arrangements; Removing shut-down heat · CPC title

• G21C13/10

  Means for preventing contamination in the event of leakage, {e.g. double wall} · CPC title

• G21C11/08 Primary

  Thermal shields; Thermal linings, i.e. for dissipating heat from gamma radiation which would otherwise heat an outer biological shield {; Thermal insulation} · CPC title

• G21C15/12

  from pressure vessel; from containment vessel · CPC title