Nuclear accord negotiation puts pyro-processing in spotlight

As the conclusion of a new bilateral civilian nuclear accord between Seoul and Washington nears, focus has now shifted on what that new agreement may signal for Korea’s efforts to develop pyro-processing technology in order to recover uranium in spent nuclear fuel.

Washington has been reluctant to allow reprocessing and enrichment in the pact because it fears it would be harmful to global nonproliferation.

Seoul, however, has alternatively been pushing for pyro-processing technology to be allowed. The technology enables recycling useful resources from spent fuel, leaving separated plutonium, the key ingredient for making atomic bombs, mixed with other elements.

Korean experts claim this process is a more proliferation-resistant option to enable the recycling of spent nuclear fuel than conventional methods.

The preexisting method for reprocessing spent nuclear fuel, containing it in wet storage, discharges about 0.9 percent clean plutonium that can potentially be used for nuclear weaponry.

This method, often referred to as the plutonium uranium extraction (PUREX) process, produces approximately 95.6 percent uranium that can be stored.

But it also produces high-level radioactive waste that has to be stored for 10,000 years, with 0.1 percent transuranic elements and 3.4 percent short-lived fission products.

The process involves dissolving the fuel elements in concentrated nitric acid and is used in nuclear-advanced countries such as the United States and France.

By contrast, pyro-processing using dry-cask storage, designed to cool spent nuclear fuel with air rather than with water, is considered less vulnerable to external conditions, according to the Korea Atomic Energy Research Institute (Kaeri). Kaeri’s technology aims to separate and refine nuclear materials contained in spent fuels with an electrochemical method at a high temperature.

The spent fuel treatment process to recover useful materials developed by Kaeri can produce 95.1 percent uranium. It is also impossible to solely separate out plutonium through this process, and the final product, around 1.6 percent, is mixed in with transuranic elements and short-lived fission products and some uranium.

Around 3.3 percent radioactive waste is produced through the process, which has to be managed around 300 years. Kaeri built a pyro-process integrated inactive demonstration facility, also called PRIDE, and began testing operations in 2012 to address the issue of spent fuel management.

The Korea-U.S. bilateral nuclear energy pact, last amended in 1974, prohibits Korea from enriching uranium. It also bans the country from reprocessing spent nuclear fuel rods from nuclear reactors.

In 2011, the United States and South Korea signed a 10-year research and development agreement to experiment with pyro-processing technology and verify whether it is more resistant to proliferation. Korea, which derives more than a third of its energy from nuclear reactors, expects to run out of storage space for spent fuel in the next decade.

“In the initial [nuclear] agreement, [it states that] we have to receive ‘prior consent’ from the U.S.” to allow spent nuclear fuel to be reprocessed through pyro-processing, said Song Ki-chan, a senior researcher with Kaeri’s Nuclear Fuel Cycle Development Group.

Because the process of acquiring approval from the United States was so cumbersome, however, it essentially meant pyro-processing was unattainable for Seoul.

“If you wanted to develop one area, let’s say A, and there are 100 subdivisions, you would have to receive permission for A-1 to A-100. That’s why we want to get rid of such tedious procedures and be able to develop the larger picture,” Song said on his expectations for the new civilian nuclear accord.

BY KIM HAN-BYUL, SARAH KIM [sarahkim@joongang.co.kr]