The Tokai No. 2 nuclear power plant in Ibaraki Prefecture passed a major earthquake safety test on June 21, paving the way for the Nuclear Regulation Authority to approve the extension of its operational life beyond 40 years.

NRA officials visited a facility in Hyogo Prefecture on June 21 to observe a test of equipment at the currently offline nuclear plant that is designed to keep the reactor building airtight even in the event of a strong earthquake.

The test was conducted at the National Research Institute for Earth Science and Disaster Resilience, located in Miki, Hyogo Prefecture. The institute contains a building that can replicate the tremors of earthquakes.

Japan Atomic Power Co. brought in equipment designed to keep in place blowout panels attached to the wall of the Tokai No. 2 nuclear reactor building. The test was to confirm that the device operated appropriately even under the maximum shaking simulation.

The panel, measuring five meters square and weighing two tons, was shaken strongly for about 90 seconds to test if it would stay sealed. The outcome was not perfect, with a five-centimeter opening appearing as some parts were damaged by the shaking. A worker then manually sealed the panel, and airtightness was confirmed.

Japan Atomic Power will have to change the design of the equipment to ensure that it can remain sealed even if hit by the maximum expected quake.

NRA Commissioner Shinsuke Yamanaka, who observed the test, said that while additional measures were needed, there were no major technical problems in the fundamental design.

"With today's test, a major hurdle was overcome," he said.

The Tokai No. 2 nuclear power plant will reach 40 years of operation in November, but the NRA is expected to decide that the plant meets new safety standards implemented in the wake of the 2011 Fukushima nuclear accident.

However, Japan Atomic Power faces other issues beyond design conditions. For the Tokai No. 2 plant to resume operations, the consent of the Ibaraki prefectural government as well as six municipal governments in the vicinity of the plant must be obtained. However, many local governments are cautious about having operations resume.

On June 19, the Mito city assembly passed a document opposing the resumption of the plant.

Japan Atomic Power will also have to find 174 billion yen ($1.6 billion) in funds for the construction work that will be necessary for safety measures. While Tokyo Electric Power Co. Holdings Inc. has indicated it was prepared to provide financial assistance, it is still unclear if Japan Atomic Power can come up with all the money to cover the costs that can further increase.

(This article was written by Yusuke Ogawa and Toshio Kawada.)