Retiring Hamaoka Units 1 and 2, with a new Unit 6 to replace them (2008)

When a calculation about replacing plant is overtaken by its times

Read this decision as "decommissioning for safety" and you miss its centre. It was taken in 2008, before Fukushima, and what sat at the centre was cost-effectiveness rather than safety as such. Two small-output units past thirty years of commercial operation could be kept alive with successive seismic upgrades for the Tokai earthquake, or retired and replaced with a large modern reactor; the company judged replacement the better buy. What distinguishes the decision is that standing directly above the assumed source region gave that calculation a weight no other utility had to carry.

The replacement framework, however, never completed, because its other pillar — the new Unit 6 — was lost. Fukushima shut all of Hamaoka down, and Unit 6 dropped out of the long-term management policy in 2016. What was meant to be plant renewal became, in the event, a decommissioning that simply removed two reactors — and a decommissioning that will take some thirty years, into the early 2040s. A forward-looking calculation about clearing out ageing units had its outline rewritten by a violent shift in the external environment. Chubu Electric's nuclear history can be read as a case of one piece of management arithmetic being overtaken by its times.