4 JAPAN’S NUCLEAR SAFETY REGULATION POLICY
89
the current state of knowledge in the field. Regarding volcanic eruptions, in case of the Sendai nuclear power plant, the NRA judged the
risk to be negligible. This was despite Kyushu island being known for
its volcanic activity (The Japan Times 2014c). Rather than taking a
precautionary approach by addressing all possible, including disputed,
earthquake sources, it agreed to focus on the undisputed ones and took
a conservative stance on the risk of a volcanic eruption.
In contrast, the NRA took decisive action in the face of an undisputable earthquake risk. In case of the Tsuruga nuclear plant in Fukui
Prefecture, the NRA decided to conduct so-called fracture zone investigation. The aim was to make sure that the fault line the reactor was
sitting on was not an active one, thus not posing an earthquake risk. The
NRA’s definition of an active fault line states that surrounding geological layers that are approximately 120,000–130,000 years old must show
signs of displacement or deformation as a result of fault line activity. While
the operator, the Japan Atomic Power Co., claimed the fault line was
inactive and even applied for a restart permit, the NRA conducted an
investigation with a strong element of on-the-ground activity. Instead of
considering information provided by the utility, the NRA sent experts to
conduct excavations around the fault line in question and thus collected
their own data. Ultimately, the NRA came to the conclusion that the fault
line underneath reactor number 1 was in fact active (NRA Commission
2014). After confirming that the fault line was active, the NRA refused a
restart permit, leading to the permanent shut down of reactor number 1
at the Tsuruga nuclear plant. Reactor number 2 was still under review at
the time of writing.
The NRA also proved relentless in the face of apparent mismanagement. In 2013, the NRA criticised how the Japan Atomic Energy Agency
(JAEA) maintained the Monju fast breeder nuclear reactor. During two
on-site safety inspections, irregularities surfaced. In response, the NRA
ordered the JAEA to revise Monju’s operational safety programme.
However, the NRA later found out that the JAEA submitted a report
about the requested revisions before completing them. During another
on-site inspection, more irregularities surfaced (NRA 2014a). With problems persisting, the NRA acted in November 2015. It issued its first
recommendation (kankoku), in which it concluded that the “JAEA does
not have the capacity to operate Monju safely”. The recommendation
indicated that a failure to find a new operator would lead to the NRA
89
the current state of knowledge in the field. Regarding volcanic eruptions, in case of the Sendai nuclear power plant, the NRA judged the
risk to be negligible. This was despite Kyushu island being known for
its volcanic activity (The Japan Times 2014c). Rather than taking a
precautionary approach by addressing all possible, including disputed,
earthquake sources, it agreed to focus on the undisputed ones and took
a conservative stance on the risk of a volcanic eruption.
In contrast, the NRA took decisive action in the face of an undisputable earthquake risk. In case of the Tsuruga nuclear plant in Fukui
Prefecture, the NRA decided to conduct so-called fracture zone investigation. The aim was to make sure that the fault line the reactor was
sitting on was not an active one, thus not posing an earthquake risk. The
NRA’s definition of an active fault line states that surrounding geological layers that are approximately 120,000–130,000 years old must show
signs of displacement or deformation as a result of fault line activity. While
the operator, the Japan Atomic Power Co., claimed the fault line was
inactive and even applied for a restart permit, the NRA conducted an
investigation with a strong element of on-the-ground activity. Instead of
considering information provided by the utility, the NRA sent experts to
conduct excavations around the fault line in question and thus collected
their own data. Ultimately, the NRA came to the conclusion that the fault
line underneath reactor number 1 was in fact active (NRA Commission
2014). After confirming that the fault line was active, the NRA refused a
restart permit, leading to the permanent shut down of reactor number 1
at the Tsuruga nuclear plant. Reactor number 2 was still under review at
the time of writing.
The NRA also proved relentless in the face of apparent mismanagement. In 2013, the NRA criticised how the Japan Atomic Energy Agency
(JAEA) maintained the Monju fast breeder nuclear reactor. During two
on-site safety inspections, irregularities surfaced. In response, the NRA
ordered the JAEA to revise Monju’s operational safety programme.
However, the NRA later found out that the JAEA submitted a report
about the requested revisions before completing them. During another
on-site inspection, more irregularities surfaced (NRA 2014a). With problems persisting, the NRA acted in November 2015. It issued its first
recommendation (kankoku), in which it concluded that the “JAEA does
not have the capacity to operate Monju safely”. The recommendation
indicated that a failure to find a new operator would lead to the NRA