Other accidents-1980s

1
Other accidents-1980s

• March 13, 1980 - Orléans, France - Nuclear
  materials leak
• A brief power excursion in Reactor A2 led to a
  rupture of fuel bundles and a minor release (8 x
  1010 Bq) of nuclear materials at the
  Saint-Laurent Nuclear Power Plant. The reactor
  was repaired and continued operation until its
  decommissioning in 1992.
• March, 1981 - Tsuruga, Japan Overexposure of
  workers
• Overexposure of workers More than 100 workers
  were exposed to doses of up to 155 millirem per
  day radiation during repairs of a nuclear power
  plant, violating the company's limit of 100
  millirems (1 mSv) per day.
• September 23, 1983 Buenos Aires, Argentina -
  Accidental criticality
• An operator error during a fuel plate
  reconfiguration in an experimental test reactor
  led to an excursion of 31017 fissions at the
  RA-2 facility. The operator absorbed 2000 rad (20
  Gy) of gamma and 1700 rad (17 Gy) of neutron
  radiation which killed him two days later.
  Another 17 people outside of the reactor room
  absorbed doses ranging from 35 rad (0.35 Gy) to
  less than 1 rad (0.01 Gy).
• April 26, 1986 Prypiat, Ukraine (then USSR) -
  Power excursion, explosion, complete meltdown
• A mishandled reactor safety test led to an
  uncontrolled power excursion, causing a severe
  steam explosion, meltdown and release of
  radioactive material at the Chernobyl nuclear
  power plant located approximately 100 kilometers
  north-northwest of Kiev.
• May 4, 1986 Hamm-Uentrop, Germany (then West
  Germany) - Fuel damage
• A spherical fuel pebble became lodged in the pipe
  used to deliver fuel elements to the reactor at
  an experimental 300-megawatt THTR-300 HTGR.
  Attempts by an operator to dislodge the fuel
  pebble damaged its cladding, releasing radiation
  detectable up to two kilometers from the reactor.
  
• November 24, 1989 Greifswald, Germany (then
  East Germany) - Fuel damaged
• Operators disabled three of six cooling pumps to
  test emergency shutoffs. Instead of the expected
  automatic shutdown a fourth pump failed causing
  excessive heating which damaged ten fuel rods.
  The accident was attributed to sticky relay
  contacts.

2
Other Accidents 1990s

• April 6, 1993 Tomsk, Russia Explosion
• A pressure buildup led to an explosive mechanical
  failure in a 34 cubic meter stainless steel
  reaction vessel buried in a concrete bunker under
  building 201 of the radiochemical works at the
  Tomsk-7 Siberian Chemical Enterprise plutonium
  reprocessing facility. The vessel contained a
  mixture of concentrated nitric acid, uranium
  (8757 kg), plutonium (449 g) along with a mixture
  of radioactive and organic waste from a prior
  extraction cycle. The explosion dislodged the
  concrete lid of the bunker and blew a large hole
  in the roof of the building, releasing
  approximately 6 GBq of Pu 239 and 30 TBq of
  various other radionuclides into the environment.
  The contamination plume extended 28 km NE of
  building 201, 20 km beyond the facility property.
  The small village of Georgievka (pop. 200) was at
  the end of the fallout plume, but no fatalities,
  illnesses or injuries were reported. The accident
  exposed 160 on-site workers and almost two
  thousand cleanup workers to total doses of up to
  50 mSv (the threshold limit for radiation workers
  is 100 mSv per 5 years)
• June, 1999 - Ishikawa Prefecture, Japan -
  Control rod malfunction
• Operators attempting to insert one control rod
  during an inspection neglected procedure and
  instead withdrew three causing a 15 minute
  uncontrolled sustained reaction at the number 1
  reactor of Shika Nuclear Power Plant. The
  Hokuriku Electric Company who owned the reactor
  did not report this incident and falsified
  records, covering it up until March, 2007.
• September 30, 1999 INES Level 4 - Ibaraki
  Prefecture, Japan - Accidental criticality
• Workers put uranyl nitrate solution containing
  about 16.6 kg of uranium, which exceeded the
  critical mass, into a precipitation tank at a
  uranium reprocessing facility in Tokai-mura
  northeast of Tokyo, Japan. The tank was not
  designed to dissolve this type of solution and
  was not configured to prevent eventual
  criticality. Three workers were exposed to
  (neutron) radiation doses in excess of allowable
  limits. Two of these workers died. 116 other
  workers received lesser doses of 1 mSv or greater
  though not in excess of the allowable limit..

3
Other accidents -2000s

• April 10, 2003 - Paks, Hungary - Fuel damaged
• Partially spent fuel rods undergoing cleaning in
  a tank of heavy water ruptured and spilled fuel
  pellets at Paks Nuclear Power Plant. It is
  suspected that inadequate cooling of the rods
  during the cleaning process combined with a
  sudden influx of cold water thermally shocked
  fuel rods causing them to split. Boric acid was
  added to the tank to prevent the loose fuel
  pellets from achieving criticality. Ammonia and
  hydrazine were also added to absorb iodine-131.
• April 19, 2005 Sellafield, England, United
  Kingdom - Nuclear material leak
• Twenty metric tons of uranium and 160 kilograms
  of plutonium dissolved in 83,000 literes of
  nitric acid leaked over several months from a
  cracked pipe into a stainless steel sump chamber
  at the Thorp nuclear fuel reprocessing plant. The
  partially processed spent fuel was drained into
  holding tanks outside the plant.
• November 2005 Braidwood, Illinois, United
  States - Nuclear material leak
• Tritium contamination of groundwater was
  discovered at Exelon's Braidwood station.
  Groundwater off site remains within safe drinking
  standards though the NRC is requiring the plant
  to correct any problems related to the release.
• March 6, 2006 Erwin, Tennessee, United States -
  Nuclear material leak
• Thirty-five liters of a highly enriched uranium
  solution leaked during transfer into a lab at
  Nuclear Fuel Services Erwin Plant. The incident
  caused a seven-month shutdown and a required
  public hearing on the licensing of the plant.