Argonne releases small modular reactor waste evaluation report

Study one of many first to handle nuclear waste manufacturing of small modular reactors.

Nuclear vitality is a key part of decarbonizing our financial system, however giant nuclear reactors are sometimes difficult and costly to construct. To make nuclear energy extra obtainable and enticing, builders have put ahead a number of designs of small modular reactors (SMRs) which have better flexibility and supply decrease up-front prices. Different kinds of SMRs with superior reactor design options are presently beneath growth within the United States and worldwide.

Researchers consider SMRs could possibly be deployed at quite a lot of scales for domestically distributed electrical energy technology. SMRs have roughly a tenth to a 3rd of the ability output of huge gentle water reactors, that are the commonest type of nuclear reactor in industrial operation within the United States. The applied sciences and economics of SMRs have been broadly studied; nevertheless, there may be much less details about their implications for nuclear waste. “We’ve really just begun to study the nuclear waste attributes of SMRs,” stated senior nuclear engineer Taek Kyum Kim of the U.S. Department of Energy’s (DOE) Argonne National Laboratory.

Kim and his colleagues from Argonne and DOE’s Idaho National Laboratory have just lately printed a report that endeavors to measure the potential nuclear waste attributes of three completely different SMR applied sciences utilizing metrics developed by an intensive course of throughout a comprehensive assessment of nuclear fuel cycles printed in 2014. Although SMRs should not but in industrial operation, a number of firms have collaborated with the DOE to discover completely different prospects for SMRs, and the three designs studied within the report are all scheduled to be constructed and operational by the tip of the last decade.

One kind of SMR, referred to as VOYGR and in growth by NuScale Power, relies on a present typical pressurized water reactor design however scaled down and modularized. Another kind, referred to as Natrium and being developed by TerraPower, is sodium-cooled and runs on a metallic gas. A 3rd kind, referred to as the Xe-100 and developed by X-energy, is cooled by helium fuel.

In phrases of nuclear waste, every reactor provides each benefits and drawbacks over giant LWRs, Kim stated. “It’s not correct to say that because these reactors are smaller they will have more problems proportionally with nuclear waste, just because they have more surface area compared to the core volume,” he stated. “Each reactor has pluses and minuses that rely upon the discharge burnup, the uranium enrichment, the thermal efficiency and different reactor-specific design options.”

One notable issue that influences the quantity of nuclear waste produced by a reactor known as burnup, and it refers back to the quantity of thermal vitality produced from a sure amount of gas. The Natrium and Xe-100 reactors have considerably larger burnup than LWRs, Kim stated. The next burnup is correlated with decrease nuclear waste manufacturing as a result of gas is transformed extra effectively to vitality. These designs even have larger thermal effectivity, which refers to how effectively the warmth produced by the reactor is transformed into electrical energy. The VOYGR pressurized water reactor design, due partially to its small size, has a barely decrease burnup and thermal effectivity in comparison with a bigger pressurized water reactor.

The spent gas attributes fluctuate considerably between the designs, with VOYGR being just like LWRs, Natrium producing a extra concentrated waste with completely different long-lived isotopes, and Xe-100 producing a decrease density however bigger quantity of spent gas.

“All advised, on the subject of nuclear waste, SMRs are roughly comparable with typical pressurized water reactors, with potential benefits and weaknesses relying on which facets you are attempting to design for,” Kim stated. “Overall, there appear to be no additional major challenges to the management of SMR nuclear wastes compared to the commercial-scale large LWR wastes.”