MOLTEN NUCLEAR FUEL SALTS AND RELATED SYSTEMS AND METHODS
This disclosure describes nuclear fuel salts usable in certain molten salt reactor designs and related systems and methods. Binary, ternary and quaternary chloride fuel salts of uranium, as well as other fissionable elements, are described. In addition, fuel salts of UCl x F y are disclosed as well as bromide fuel salts. This disclosure also presents methods and systems for manufacturing such fuel salts, for creating salts that reduce corrosion of the reactor components and for creating fuel salts that are not suitable for weapons applications.
1 . A nuclear reactor facility for generating power from a nuclear reaction, the reactor facility comprising:
a reactor core containing a fissionable fuel salt, the fissionable fuel salt having at least 5% by molar fraction UCl 4 and wherein the fuel salt has a melting point of less than 600° C.; and
a heat exchanger adapted to transfer heat from the fuel salt to a coolant.
2 . The nuclear reactor of claim 1 wherein the molar fraction of UCl 4 is from 5% to 100% by molar fraction UCl 4 .
3 . The nuclear reactor of claim 2 wherein the molar fraction of UCl 4 is from 13% to 71% by molar fraction UCl 4 .
4 . The nuclear reactor of claim 1 , wherein the fissionable fuel salt has from 0% to 34% by molar fraction UCl 3 .
5 . The nuclear reactor of claim 1 wherein the fissionable fuel salt has from 12% to 67% by molar fraction NaCl.
6 . The nuclear reactor of claim 1 wherein the melting point is from 330 to 550° C.
7 . The nuclear reactor of claim 6 wherein the melting point is from 338 to 500° C.
8 . The nuclear reactor of claim 7 wherein the melting point is from 338 to 450° C.
9 . The nuclear reactor of claim 1 wherein the fissionable fuel salt is a mixture of chloride salts in which chloride ions in the chloride salts have a first ratio of 37 Cl to total Cl, the first ratio being different than a naturally occurring ratio of 37 Cl to total Cl.
10 . The nuclear reactor of claim 9 wherein 25% or more of the chloride ions in the mixture of chloride salts are 37 Cl.
11 . The nuclear reactor of claim 1 wherein the fissionable fuel salt is a mixture of UCl 4 and one or more of UCl 3 , UCl 3 F, UCl 2 F 2 , UClF 3 , ThCl 4 , NaCl, MgCl 2 , CaCl 2 , BaCl 2 , KCl, SrCl 2 , VCl 3 , CrCl 3 , TiCl 4 , ZrCl 4 , ThCl 4 , AcCl 3 , NpCl 4 , AmCl 3 , LaCl 3 , CeCl 3 , PrCl 3 and/or NdCl 3 .
12 . The nuclear reactor of claim 1 wherein the fissionable fuel salt is a mixture of UCl 4 and at least one lanthanide, the fissionable fuel salt having a Figure of Merit that is less than 1.0.
13 . A method of operating a nuclear reactor comprising:
supplying a reactor core with a fissionable fuel salt containing an amount of UCl 4 and one or more of UCl 3 F, UCl 3 , UCl 2 F 2 , UClF 3 , and a non-fissile salt selected from NaCl, MgCl 2 , CaCl 2 , BaCl 2 , KCl, SrCl 2 , VCl 3 , CrCl 3 , TiCl 4 , ZrCl 4 , ThCl 4 , AcCl 3 , NpCl 4 , AmCl 3 , LaCl 3 , CeCl 3 , PrCl 3 , and NdCl 3 , wherein the fuel salt has a melting temperature below 800° C. and a uranium content of approximately 61% by weight;
initiating fission in the fissionable fuel salt; and
maintaining breed-and-burn behavior in the fissionable fuel salt for a period of time, thereby creating an irradiated fuel salt.
14 . The method of claim 13 wherein the initiating and maintaining operations are performed at a temperature below 550° C. but above the melting temperature of the fissionable fuel salt.
15 . The method of claim 13 further comprising:
removing irradiated fuel salt from the reactor core;
contacting the irradiated fuel salt from the reactor core with a carrier gas, thereby creating a carrier/fission product gas mixture and a degassed fuel salt having a reduced amount of gaseous fission products relative to the irradiated fuel salt;
filtering the degassed fuel salt, thereby removing fission product solids, to obtain a filtered fuel salt; and
transferring the filtered fuel salt to the reactor core.
16 . The method of claim 13 further comprising:
prior to initiating fission in the fissionable fuel salt, adding at least one radioactive isotope to the fissionable fuel salt in an amount sufficient to obtain a fissionable fuel salt having a Figure of Merit that is less than 1.0.
17 . The method of claim 13 wherein chloride ions in the fissionable fuel salt have a first ratio of 37 Cl to total Cl, the first ratio being different than a naturally occurring ratio of 37 Cl to total Cl.
18 . The method of claim 13 wherein the fissionable fuel salt contains UCl 4 and one or more of UCl 3 and NaCl.
19 . The method of claim 13 wherein the molar fraction of UCl 4 in the fissionable fuel salt is from 13 mol % to 71 mol % UCl 4 .
20 . A fissionable fuel salt comprising:
at least 5% by molar fraction UCl 4 ;
wherein the fissionable fuel salt has a melting point of less than 600° C.