IAEA confirms nuclear security improvements at Japanese plant

02 April 2024

Physical protection measures at Japan's seven-unit Kashiwazaki-Kariwa nuclear power plant have been significantly strengthened over recent years, according to the International Atomic Energy Agency. The finding came as Tokyo Electric Power Company submitted a plan to the nuclear regulator to begin loading fuel into unit 7 of the plant later this month.

Kashiwazaki-Kariwa (Image: Tepco)

An International Atomic Energy Agency (IAEA) team of experts has completed a nuclear security mission at the plant in Japan's Niigata Prefecture, which was carried out at the request of Tokyo Electric Power Company (Tepco). The nine-day mission - conducted from 25 March to 2 April - aimed to assess the enhancement of the physical protection measures at the plant and to provide further advice as necessary to the facility's operator.

The five-person team assessed and observed physical protection measures against the Convention on the Physical Protection of Nuclear Material as amended, and relevant IAEA Nuclear Security Guidance documents. They visited the plant and met with Tepco staff. The team included experts from Finland, the UK and the USA, as well as one IAEA staff member.

The team observed the facility management's commitment to improving nuclear security and identified continuous improvements in several areas of the plant's physical protection system since 2018, when the IAEA conducted an International Physical Protection Advisory Service Follow-up Mission in Japan, including a site visit at Kashiwazaki-Kariwa. It noted most of the improvements have been completed, and some requiring significant resources and time to complete are either under implementation or planned to be implemented. The team provided Tepco recommendations and suggestions for further improvements.

"Critical infrastructure, such as nuclear facilities, requires robust physical protection measures, as part of a national nuclear security regime supported by a legislative and regulatory framework and nuclear security culture," said Elena Buglova, director of the IAEA's Division of Nuclear Security. "The IAEA expert missions are intended to assist the requesting States in establishing and further strengthening their national nuclear security regimes, including the physical protection against theft, sabotage or unauthorised use of nuclear and other radioactive material."

"The findings provided by the experts of the expert mission team are very important and will be used further to enhance nuclear security of our plant in line with the IAEA international standards," said Takeyuki Inagaki, superintendent of the Kashiwazaki-Kariwa plant. "Based on the advice given by the IAEA experts, Tepco is committed to continuously improve our security measures by establishing a strong security culture to sustain this current security enhancement effort and prevent it from declining again in the future.

"Also, we will further strengthen the prevention measures against internal threat and continue our improvement aiming towards a better physical protection system, including intrusion detection. This expert mission has also provided us a great opportunity to learn about international good practices. We will continue to improve towards a plant, which our local region can trust and feel safe about."

Approval sought for fuel loading

Tepco applied for Nuclear Regulation Authority (NRA) approval of its design and construction plan for Kashiwazaki-Kariwa units 6 and 7 in September 2013. It submitted information on safety upgrades across the site and at those two units. These 1356 MWe Advanced Boiling Water Reactors began commercial operation in 1996 and 1997 and were the first Japanese boiling water reactors to be put forward for restart.

In 2017, Tepco received permission from the NRA to restart units 6 and 7. Local government consents are still required before the reactors can be restarted.

However, in April 2021 the NRA issued an administrative order to Tepco prohibiting it from moving nuclear fuel at the plant until improvements in security measures there had been confirmed by additional inspections. The order followed the disclosure by Tepco of faulty intruder detection equipment at the site as well as the unauthorised use of an ID card.

This administrative order was lifted in December.

On 28 March, Tepco submitted a plan to the NRA to begin loading fuel into Kashiwazaki-Kariwa unit 7 on 15 April. The company noted, "At this time, there is no forecast for the subsequent steps, so the specific [restart] scheduled date is listed as undetermined."

The Kyodo news agency reported that after loading fuel into unit 7, Tepco hopes to bring it to criticality and ascertain whether any irregularities are present before gradually increasing its output.

However, the unit can only attain criticality once local approval has been received.

Although it has completed work at the other idled units at Kashiwazaki-Kariwa, Tepco is concentrating its resources on units 6 and 7 while it deals with the clean-up at Fukushima Daiichi. Restarting those two units - which have been offline for periodic inspections since March 2012 and August 2011, respectively - would increase the company's earnings by an estimated JPY100 billion (USD659 million) per year.

Researched and written by World Nuclear News