Patent Number: 
Section: claims

1. A method for preparing spent nuclear fuel for dry storage using a gas drying system, the method comprising:(a) flowing a non-reactive gas at through a cavity containing spent nuclear fuel;(b) repetitively measuring dew point temperatures of the non-reactive gas exiting the cavity via a moisture-sensing device;(c) drying the non-reactive gas that exits the cavity with a moisture removal apparatus after the dew point temperature is measured;(d) re-circulating the dried non-reactive gas back through the cavity after drying the non-reactive gas in a closed flow loop;(e) transmitting the measured actual dew point temperatures from the moisture-sensing device to a programmable logic controller;(f1) the controller comparing the measured dew point temperatures of the non-reactive gas exiting the cavity to a predetermined dew point temperature;(f2) the controller activating a timer upon the measured dew point temperatures being at or below the predetermined dew point temperature, and continuing to circulate the non-reactive gas for a predetermined period of time counted by running the timer to ensure the cavity is dry; and(g) the controller discontinuing the flow of the non-reactive gas when the measured dew point temperatures are at or below the predetermined dew point temperature. 2. The method according to claim 1, wherein the moisture removal apparatus is a chiller. 3. The method according to claim 1, wherein step (d) is performed using a recirculation pump downstream of the moisture removal apparatus in the closed flow loop. 4. The method according to claim 3, further comprising a gas reservoir fluidly coupled in a serial flow arrangement in the closed flow loop downstream of the recirculation pump, wherein the recirculation pump flows the non-reactive gas through the gas reservoir under pressure. 5. The method according to claim 4, further comprising a gas supply pump fluidly coupled in a serial flow arrangement in the closed flow loop downstream of the gas reservoir, wherein activating the gas supply pump and the recirculation pump results in the non-reactive gas being drawn from the gas reservoir and flowing through the closed-loop fluid. 6. The method according to claim 5, wherein step (g) comprises the controller generating a signal to shut down the gas supply pump to discontinue the flow of the non-reactive gas. 7. The method according to claim 4, further comprising a flow rate valve arranged in the closed flow loop between the gas reservoir and the cavity, the flow rate valve configured and operable to control a flow rate of the non-reactive gas circulating through the closed flow loop. 8. The method according to claim 1, wherein the moisture sensing device is a hygrometer. 9. The method according to claim 1, further comprising after step (g) a step of the controller triggering an alarm to signal an operator that the drying process is completed. 10. The method according to claim 1, wherein the non-reactive gas is helium. 11. The method according to claim 1, further comprising after step (g) a step of the sealing the cavity. 12. The method according to claim 1, wherein step (g) is performed by the controller after expiration of the timer. 13. The method according to claim 1, wherein before step (a) performing steps of draining bulk water from a canister defining the cavity which contains the spent nuclear fuel, coupling a gas supply line of the gas drying system to an inlet of the canister, and coupling a gas exhaust line to an outlet of the canister which forms the closed flow loop. 14. The method according to claim 13, wherein before step (a) performing a step of confirming whether the gas drying system has been coupled to the canister before starting flow of the non-reactive gas.