hankyoreh

May 28. They are on alert after the shutdown of two nuclear reactors at a time of high demand. (Yonhap News)

By Lee Keun-young, science correspondent and Lee Seung-jun, staff reporter

Nuclear power has run into another hitch. This time, the problem is Shingori reactor 2 and Sinwolseong reactor 1. An investigation revealed that the safety of the control cables used at these reactors had not met the required standards during the testing process but that documents had been falsified to allow them to be approved anyway. With the shutdown at these reactors, operations are now suspended at 10 of the South Korea’s 23 nuclear reactors. Combined with expectations that this summer will be longer - and muggier - than usual, energy supply is facing a crisis.

On the morning of May 28, the Nuclear Safety and Security Commission (NSSC) held an emergency press conference and announced that it had determined that the test scores of the control cables that had been supplied to Singori reactors 1 and 2 and Sinwolseong reactors 1 and 2 had been fabricated by the testing agency. After conducting a safety test on the installed cables, it was decided that the cables needed to be replaced, so the reactors were shut down, the NSSC said.

“At the end of last month, we received a tip that the documents for parts at Singori reactors 3 and 4 had been fabricated,” said Lee Un-chul, chief regulatory officer at the NSSC. “When we expanded our investigation to include Shingori reactors 1 and 2 and Sinwolseong reactors 1 and 2, we found that, while only the graphs had been falsified in the documents for Shingori 3 and 4, test results for parts in the other four reactors had been falsified with failures reported as successes.”

Control cables are safety equipment that signal safety mechanisms - including reactor cooling equipment - to kick in when an accident occurs. These cables are supposed to be able to resist high temperatures and high pressure, but the investigation revealed that the cables that had been installed at the reactors in question failed to meet standards.

The NSSC plans to extend the Shingori No. 1 reactor’s scheduled preventive maintenance period, which has been under way since early April, in order to replace the parts. In the case of the Sinwolseong No. 2 reactor, the operational permit of which is currently under review, the cables in question need to be changed before the issuance of the permit. For the Shingori No. 2 reactor and Sinwolseong No. 1 reactor, which are respectively slotted to have regular maintenance on May 31 and June 21, a shutdown is required to switch out control cables.

The Ministry of Trade, Industry and Energy explained the timetable, saying that after the NSSC made its decision to replace cables at the four plants, plans were set to carry out the effort to change the cables in question as quickly as possible.

The cables in question are huge, each reactor’s stretching out for 5 kilometers. It is likely to take at least five to six months to finish the entire process of acquiring new parts, installing them, and checking to see if they work properly. This spells potential difficulties for meeting summer and winter electricity demand. The MTIE is working on a backup supply plan, setting up an emergency electricity supply headquarters and hurrying along the completion of power plants that are now under construction. It also plans to take civil and criminal action against the organizations and individuals responsible for falsifying documents, including possible criminal complaints and damage claims.

Plans are also being set for the Shingori No. 3 reactor, which is the focal point in a recent controversy over electricity transmission tower construction in Miryang, South Gyeongsang Province.

“So far in our inspection, we’ve only uncovered forged documents in the cases of the No. 3 and 4 reactors at Shingori,” explained Lee Eun-cheol, president of the NSSC. “But we are now planning to conduct a safety assessment on the control cables there and take any necessary steps.”

The installation of control cables based on documents forged by a parts testing organization suggests serious issues with the overall quality of the nuclear power plant safety system. The four power plants shut down or delayed on May 28 - the No. 1 and 2 reactors at Shingori and Sinwolseong - all went on line in the past year or two, which would mean their parts were supplied in 2008. This, in turn, means that Korea Hydro & Nuclear Power (KHNP) and the NSSC put them into operation (or attempted to) for five years without any knowledge of the faulty control cables. And the altering of the testing results might not have been detected at all had the authorities not been tipped off.

The investigation uncovered evidence that the organization commissioned to test the cables’ performance falsified its reports by altering graphs and other results to make it appear that they met the necessary conditions. Control cables are a crucial component in a nuclear power plant: if they were to fail in an emergency, it could lead to a failure to cool nuclear fuel, or even a leakage of radiation. To earn certification, they have to go through a simulated loss-of-coolant accident (LOCA), in which they are subjected to temperatures of over 190 degrees for six hours before being immersed once again in water.

But no institution in South Korea is equipped to conduct this test. Instead, a domestic organization asked a Canadian one to conduct the test and provide results for the parts. The documents showed only three of twelve specimens earning a passing grade, but an employee at the South Korean institution falsified the overall performance results by including findings for just two of the specimens that passed. Graphs and findings for the No. 1 and 2 reactors at Shingori and Sinwolseong were found to have been completely made up; for the Shingori No. 3 and 4 reactors, graphs were doctored.

The most troubling part of the forgery is that the KHNP and safety regulatory organizations failed to detect when a domestic testing organization doctored its own findings. In the past, a document review was sufficient to uncover cases where nuclear power plant parts suppliers altered the results issued by a domestic or overseas testing organization.

Lee Eun-cheol addressed the problem frankly during a May 27 press conference.

“Unless there’s a serious problem with the documents submitted by a domestic testing organization, it’s difficult to detect any falsification,” he said.

Another problem is the lack of any effective means of preventing testing organizations from falsifying documents. The shortage of workers to enforce nuclear safety regulations has been mentioned every time a case of power plant malfunctioning has come up.

Indeed, South Korea’s average of 18.46 workers per reactor is less than the half the 37.7 in the US or the 44.3 in Canada.

“A testing organization doctoring findings is the unthinkable becoming reality,” said Suh Kune-yull, a professor of nuclear engineering at Seoul National University. “Increase the number of workers all you want, but you’ll never fix the problem as long as it all gets handled internally through document examinations.”

“For the questionable power plants, we need to adopt a ‘surgical’ method of shutting the reactors down and disassembling the parts to closely examine them,” Suh advised.

Please direct questions or comments to [english@hani.co.kr]