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252 Beyond Decommissioning

superstructures at each corner are connected by the protruding ledge. A cafe connected
to the balcony through a glass wall and an event space were also installed on the upper
level. To stabilize the structure, concrete was sprayed onto the crumbling facade and
the cafe was thermally insulated. Inside the structure, the damaged floors were chan-
ged; the renovated structure was completed by an elevator and stairways.
3
A 2000-m water reservoir, serving as large thermal buffer, is installed at the center
of the building. The reservoir is fed by heat from a biomass thermal power plant, a
wood burning unit, solar panels installed on the roof and waste heat from a close indus-
trial factory. The heat is redistributed to the neighborhood. PV panels installed on the
south side and a thermal power station feed the electrical network (Dezeen, 2014a).

6.7 Others

This chapter is about mutually unrelated facilities and site features that need specific
conversion modes.

6.7.1 Naval installations
An extensive database of nuclear ships (aircraft carriers, cargo ships, icebreakers) and
submarines and their operating experience is given in WNA (2017). Factors leading to
decommissioning are also given. The following is a brief summary of conversion pro-
jects for some of these installations.

6.7.1.1 Mutsu nuclear ship, Japan (Mutsu, 1996)
Mutsu was Japan’s only nuclear-powered ship. It was built as a nuclear merchant ship,
but never carried commercial cargo. The ship left Japan in August 1974, and the reac-
tor reached criticality in the open ocean on 28 August. A few days later a minor shield-
ing problem appeared, which let a stream of radiation out of the reactor shielding.
There was no significant staff exposure, but the incident became a political issue, with
local fisherman blocking return of the ship to port for more than 50 days. Eventually
the ship returned to another Japanese port. In 1978–82 various modifications were
made to the reactor shield. Through a thorough examination and repair of machinery,
the Mutsu was completely refurbished by February 1991. She then completed her orig-
inal testing goal of travelling 82,000 km, and was decommissioned in 1992.
The reactor was taken away in 1995. After decontamination, the Mutsu was reborn
as the oceanographic vessel Mirai.
Built in the shape of the original vessel the Mutsu Science and Technology
Museum opened in 1996. The main feature of the museum is the view of the upper
portion of the actual reactor. Through leaded-glass windows visitors can view the
reactor, surrounded by thick concrete walls, as well as control rod mechanisms and
other equipment.