Dream Technology vs Money Pit... What is 'Pyroprocessing'? [Reading Science]

[Asia Economy Reporter Kim Bong-su] Recently, following the approval of a Korea-US joint research report, controversy surrounding spent nuclear fuel reprocessing technology, namely 'pyroprocessing,' and sodium-cooled fast reactors (SFR) has resurfaced. The debate between proponents who call it a "dream technology that offsets the drawbacks of nuclear power generation" and critics who dismiss it as "a mirage-like fiction aimed at securing research funds" remains intense. So, who is actually right?

According to the Korea Atomic Energy Research Institute, pyroprocessing is a technology that separates and recycles reusable nuclear fuel and waste from spent nuclear fuel. It is similar to sorting and recycling cans and plastics from household waste. When a reactor operates, a large amount of spent nuclear fuel is produced, from which uranium (94%) and transuranic elements (1.5%) are extracted for reuse or as fuel for sodium-cooled fast reactors, while the remaining waste (4.5%) is stored long-term and then disposed of after lowering its radioactivity to intermediate and low levels.

This technology was devised to process spent nuclear fuel from nuclear power plants. Since spent nuclear fuel emits radiation and high heat for a long time, many countries using nuclear power have struggled to find management and disposal solutions. Currently, it is temporarily stored in pools at each power plant, and as of 2019, the amount exceeded about 40,000 tons, with storage capacity expected to be exceeded within the 2020s. If this technology is commercialized, the transuranic elements in spent nuclear fuel can be used as fuel for SFRs, and by separating and storing high-heat radionuclides, the Korea Atomic Energy Research Institute claims that the disposal area and storage time for high-level waste can be drastically reduced. For example, if a high-level waste disposal site requires 7,500㎡ before pyroprocessing, it would be reduced to 80㎡ afterward, and the storage period for radioactivity to decrease to natural levels would be dramatically shortened from 300,000 years to 300 years.

Since plutonium, which can be used as material for nuclear bombs, can be extracted during the spent nuclear fuel reprocessing, there is a 'nuclear non-proliferation' concern. However, the Korea Atomic Energy Research Institute states that plutonium extraction is impossible with the dry pyroprocessing method itself. If this technology becomes practical, it would indeed be a 'dream technology.' The biggest drawback of nuclear power generation is the difficulty and high cost of disposing and managing high-level waste, which this technology could solve. Meanwhile, the sodium-cooled fast reactor, which operates using transuranic elements produced after pyroprocessing, is linked to the 'small modular reactor' technology recently gaining attention as the next-generation nuclear power technology. The reactor 'Natrium,' which Bill Gates is focusing on, is a sodium-cooled reactor using sodium as a coolant.

The problem is that the technological and economic feasibility has not yet been proven. Korea and the US have jointly researched pyroprocessing-SFR technology for the past decade to verify it, and the recent report has been approved by authorities in both countries. Some claim that the report contains positive content regarding economic feasibility and technical stability, signaling a green light for demonstration projects and commercialization. However, the Ministry of Science and ICT officially denied this, stating, "The report contains only facts, and it is not true that a positive conclusion has been drawn." They also plan to verify whether to continue the research through an appropriateness committee in the future.

Opponents point out several drawbacks of pyroprocessing. First, safety has not been verified. There is a risk of radiation leakage during the collection of spent nuclear fuel, and the safety of fast reactors is also problematic. Just as the Chernobyl reactor in the former Soviet Union exploded using graphite as a coolant, sodium can explode upon contact with air, making it a potential cause of nuclear disasters. Despite spending over 100 trillion won worldwide over several decades developing fast reactors, no successful cases exist. Cost is also an issue. Opponents argue that one fast reactor must be built for every two pressurized water reactors, and since the lifespan is about 50 years, hundreds would need to be built, resulting in astronomical costs. They say it would be much cheaper to build an interim processing facility instead.

It is time to focus on achieving the 2050 carbon neutrality goal to prevent global warming. If nuclear reactors that emit no carbon can overcome their fatal weaknesses through pyroprocessing technology, nothing could be better. However, science and technology are not politics or ideology. Above all, the safety of the public, technical completeness, and economic feasibility must be reasonably proven. This is not the time for a political or ideological tug-of-war like the anti-nuclear debate. Practical discussions based on principles and science must take place.