A patented Fluidized Bed Steam Reforming (FBSR) expertise makes use of superheated steam—as a substitute of an open flame—and mineralizing components to deal with and immobilize radionuclides in a water-insoluble matrix. Results present a 6:1 common quantity discount for ion-exchange resins, which permits disposal with out getting into into larger, more-restrictive and costly waste classifications. Since preliminary pilot research starting in 1997, FBSR expertise has been deployed within the U.S., Japan, and France.
The nuclear trade yearly produces voluminous quantities of radioactively contaminated ion-exchange resins (IERs) comprised of natural materials, normally a styrene polymer containing sulfonic acid and amine teams. The resins, for instance, are used to pay attention and take away activation, corrosion, and fission-product radionuclides from nuclear plant liquid waste streams. Traditional high-temperature, flame-induced combustion remedy processes (reminiscent of incineration) kind and launch sulfur and nitrogen oxides, together with vaporization of cesium-137, requiring high-performance filtering techniques. The retained radioactively contaminated fly ash is solidified and containerized based on transportation and low-level radioactive waste (LLRW) disposal laws.
Following numerous pilot research starting in 1997, Studsvik developed and patented a non-incineration Fluidized Bed Steam Reforming (FBSR) expertise—that makes use of steam—to deal with quite a lot of LLRWs containing excessive natural, nitrate, nitrite, solids, and heavy-metal content material, whereas producing a dry, steady, granular, remaining waste kind. Because there isn’t a flame current within the major waste remedy vessel, the remedy course of just isn’t thought-about incineration. Additional benefits embrace no liquid effluents apart from water vapor and Clean Air Act-compliant off-gas emissions.
Treating Low-Level Radioactive Wastes
POWER interviewed Adam Foster, PE, head of engineering companies with Studsvik Inc., who relies in Atlanta, Georgia, for particulars concerning the FBSR expertise. One location that makes use of FBSR expertise is the Erwin Resin Solutions (ERS) Facility positioned in Erwin, Tennessee (Figure 1). It is a production-scale, shielded facility that homes tools for dealing with and changing LLRW into an inert, steady, and volume-reduced remaining waste kind.
|1. Volume discount in a small footprint. The Erwin Resin Solutions (ERS) Facility in Erwin, Tennessee, has been in operation since 1999. It has obtained greater than three,000 shipments and handled larger than 11,300 cubic meters of low-level waste. Various forms of wastes have been handled on the ERS facility, however they’ve primarily consisted of ion-exchange resins. VitalitySolutions bought Studsvik’s processing facility in 2014. Courtesy: Studsvik Inc.|
Studsvik’s FBSR waste decomposition course of makes use of steam pyrolysis as an alternative choice to incineration and different conventional thermal remedy strategies. This yields a stable, inert, steady, and considerably smaller quantity waste matrix, whereas assembly all federal and state radioactive waste processing legal guidelines, codes, and requirements.
Foster described how spent IERs from industrial nuclear vegetation are shipped to the ERS and transferred as a water/IER slurry to waste holding tanks positioned in shielded vaults. After the IERs settle within the holding tanks, extra water is decanted from the highest.
Mixing the settled IERs creates a homogenous combination, which is transferred to a metering tank to begin the FBSR course of. A mineralizing additive is combined with the IER as it’s metered/fed into the FBSR vessel to stop agglomerations from forming within the fluidized mattress. Other course of components, reminiscent of mineralizing clay, could also be added relying on the sort/composition of the waste and the specified remaining waste matrix sturdiness traits, which embrace water solubility and leach resistance.