The Japan Atomic Energy Agency on 30 July resumed operation of the High Temperature Engineering Test Reactor (HTTR) at the Oarai Research Institute (Ibaraki Prefecture) for the first time in 10 and a half years. The 30MW HTTR is an experimental high temperature gas-cooled reactor (HTGR). JAEA) obtained permission from the Nuclear Regulation Authority (NRA) in June 2020 for changes to the HTTR in conformity to the new regulatory requirements.

JAEA noted that, while the HTTR was not severely damaged during the 2011 earthquake and tsunami that destroyed the Fukushima Daiichi NPP, it was still required to meet the stricter regulatory requirements introduced as a result. The HTTR achieved first criticality in 1998 and attained full power operation in 2001. In 2010, HTTR was operated successfully for 50 days under high temperature and full power conditions. The reactor has been idle since February 2011, when it was taken offline for planned inspections.

JAEA said that, as the momentum toward the carbon neutrality by 2050 has built up globally and a significant role of nuclear energy, especially advanced nuclear reactors, has been increasingly recognised, HTGR is now considered one of the promising technology options both for power generation and hydrogen production.

“JAEA will carry out the safety demonstration tests by using the HTTR under the framework of OECD/NEA project. Also, JAEA has a plan to conduct various tests to confirm safety, core physics & thermal-fluid characteristics, fuel performance. Furthermore, the demonstration plan of hydrogen production by the HTTR is under discussion. Through those tests utilising HTTR and the efforts on the establishment of global safety standard we will make a contribution to the international community.”