Page 228 - Beyond Decommissioning

Experience and lessons learned 209

retailers often adapted their shops to the layout of the station and the needs of the local
community around them. However, as gas consumption has decreased, and the cost of
land has skyrocketed, many stations are closing. With their large footprint and lack of
adjacent infrastructure, gas stations offer now attractive prospects for redevelopment,
including art galleries, office spaces, and restaurants (Arch Daily, 2018b).
More than half a million underground storage tanks (USTs) in the USA alone store
petroleum or hazardous substances. The greatest threat from a leaking UST is contam-
ination of groundwater, the main source of drinking water in the country. In 2015, the
EPA issued revised UST regulations (GPO, 2015). Locations of USTs should be care-
fully researched in preparation to the redevelopment. It was common to have natural
gas and fuel oil tanks for powering the boilers in large schools or nursing homes. Fuel
oil did not commonly leak, but preparations for site redevelopment in the vicinity
should include the removal of such tanks and verification that the site (soil, ground-
water) is clean. Developers should also be aware that gasoline tanks, even if they are
not onsite, may be somewhere nearby. Gasoline leaks move easily and sideways,
meaning that a gas station or paint store may have leaked gasoline onto a redevelop-
ment site nearby. There is abundant literature about environmental risks posed by gas
stations and rehabilitation options (Cramer, 2005).
The following is a brief description of challenges posed by nuclear underground
structures and successful reuse options. The Technical (T) Building at Mound Site,
Ohio, is an underground, bomb shelter-type reinforced concrete construction, with
a 5-m thick roof, 5-m thick walls, and is supported by a 2.5-m thick slab. It is espe-
cially significant for its role in the purification of Po210 for use in nuclear weapons.
Polonium was important for its role as initiator (neutron generator) of the chain reac-
tion. The building was constructed in 1947–48 at almost half the cost of all other
16 buildings of the entire Mound Site. The T Building is a five-story building sunk
into a hillside, mostly underground, with aboveground towers and an outside-
accessible service tunnel.
In 1954, Mound began a program using Po210 to convert nuclear energy to stable
electric energy. In 1958, the first polonium-powered thermoelectric generator
(RTG) was built. The RTG provided power to a satellite radio transmitter. Pluto-
nium was eventually used as a substitute beginning in the early 1970s. The
T Building was also active in tritium applications and is therefore contaminated
by tritium (and other radioisotopes). It also housed neutron and alpha source pro-
grams. It served as storage for the Mound’s transuranic waste that had no specified
destination. After removal of this waste, Mound plans called for the T building to be
closed and the tritium contamination to decay in situ for around 100 years
(Environmental Law Institute, 1998). However as of 2004 the T Building partici-
pated in a USDOE Large-Scale Demonstration Project for Tritium Facilities to
identify, demonstrate and evaluate improved technologies applicable to the
decommissioning of excess tritium facilities.
Due to tritium relatively long half-life (12.3 years) institutional controls would be
needed to deal with any tritium contaminated buildings that are left in place; besides,
some controls may be needed to deal with the related contaminated seeps until the
contamination is eliminated or reduced.