Soviet submarine K-431
| History | |
|---|---|
 Soviet Union
|
|
| Name: | K-431 |
| Builder: | Leninskiy Komsomol Shipyard, Komsomolsk-on-Amur |
| Laid down: | 11 January 1964 |
| Launched: | 8 September 1964 |
| Commissioned: | 30 September 1965 |
| Decommissioned: | 1987 |
| Fate: | Scrapped |
| General characteristics | |
| Class and type: | Echo-class submarine |
| Displacement: |
|
| Length: | 115.4 m (378 ft 7 in) |
| Beam: | 9.3 m (30 ft 6 in) |
| Draught: | 7.4 m (24 ft 3 in) |
| Propulsion: | 2 × pressurized water-cooled reactors 70,000 hp (52 MW) each, 2 steam turbines, 2 shafts |
| Speed: |
|
| Range: | 18,000–30,000 nmi (33,000–56,000 km; 21,000–35,000 mi) |
| Endurance: | 50 days |
| Test depth: | 300 m (984 ft) |
| Complement: | 104-109 men (including 29 officers) |
| Armament: |
|
Soviet submarine K-431 (originally the Soviet submarine K-31) was a Soviet nuclear-powered submarine that had a reactor accident on 10 August 1985. It was commissioned on September 30th, 1965. An explosion occurred during refueling of the submarine at Chazhma Bay, Vladivostok. There were ten fatalities and 49 other people suffered radiation injuries. TIME magazine has identified the accident as one of the world's "worst nuclear disasters".
The K-431, completed around 1965 as unit K-31, was a Project 675 (Echo II) class submarine with two pressurized water reactors, each 70 MWt capacity and using 20% enriched uranium as fuel. On 10 August 1985, the submarine was being refuelled at the Chazhma Bay naval facility near Vladivostok. The submarine had been refuelled and the reactor tank lid was being replaced. The lid was laid incorrectly and had to be lifted again with the control rods attached. A beam was supposed to prevent the lid from being lifted too far, but this beam was positioned incorrectly, and the lid with control rods was lifted up too far. At 10:55 AM the starboard reactor became prompt critical, resulting in a criticality excursion of about 5·1018fissions and a thermal/steam explosion. The explosion expelled the new load of fuel, destroyed the machine enclosures, ruptured the submarine's pressure hull and aft bulkhead, and partially destroyed the fuelling shack, with the shack's roof falling 70 metres away in the water. A fire followed, which was extinguished after 4 hours, after which assessment of the radioactive contamination began. Most of the radioactive debris fell within 50–100 metres of the submarine, but a cloud of radioactive gas and particulates blew to the northwest across a 6 km stretch of the Dunay Peninsula, missing the town of Shkotovo-22, 1.5 km from the dock. The contaminated forest area was later surveyed as 2 km2 in a swath 3.5 km long and 200 to 650 metres wide. Initial estimates of the radioactive release were about 74 PBq (2 MCi) of noble gases and 185 PBq (5 MCi) of other fission products, but most of this was short-lived isotopes; the estimated release inventory one hour after the accident was about 37 TBq (1000 Ci) of non-noble fission products. In part because the reactor did not contain spent fuel, the fraction of biologically active isotopes was far smaller than in the case of the Chernobyl disaster.
...
Wikipedia