Magistral site (Sovkhoznoye gas storage)

The Magistral site is where an underground nuclear explosion was set off in 1970 at the Sovkhoznoye underground gas storage facility in the Oktyabrsky District of Orenburg Oblast, near the village of Mikhaylovka. The 12.3-kiloton blast created a cavity in rock salt for storing liquid hydrocarbons; today it is a decommissioned radiation-hazardous site with a fenced sanitary protection zone.

History

The Sovkhoznoye storage facility was built on a gas field discovered in 1962 near Mikhaylovka. To store gas condensate there, engineers turned to a method that had so far only been tried in experiments: melting out a cavity in rock salt with an underground nuclear explosion.

On 25 June 1970 a peaceful underground nuclear explosion with a yield of 12.3 kilotons was carried out at Sovkhoznoye. It was the first attempt to create industrial storage for liquid hydrocarbons with a nuclear blast. Before that, similar work had been done only in the experimental Galit series at the Azgir test site north-east of Astrakhan. The resulting cavity was designated E-1 and the whole site was named Magistral. A second nuclear explosion site, Sapfir, later appeared at the same storage facility.

Decommissioning of cavity E-1

In 1999 cavity E-1 was taken out of service under the 1993 regulations on the conservation and liquidation of nuclear explosion technology sites. The reason was an excessive build-up of radioactive brine, about 3,500 cubic metres.

To close the cavity, its empty space was filled with sand, then coarse rock salt was fed into the well and steam was pumped in at about 3 atmospheres and 250 °C. The well was then cemented. The work showed that the technology was reliable and met radioecological requirements.

In 2007 the Magistral and Sapfir sites were handed over to Podzemgazprom for isolation and liquidation work under Gazprom's environmental programme for radiation-hazardous sites for 2005–2010.

The site today

The sanitary protection zone of Magistral is fenced and covers 2.6 hectares. Cavity E-1 is sealed off from the surface by a cement plug and special backfill in the well. Four near-surface stores of solid low-level waste lie inside the zone.

Good to know

Sovkhoznoye is a working industrial facility, so the storage site and the protection zone are closed to visitors. The place matters mainly as a chapter in the Soviet peaceful nuclear explosions programme: the underground blast in the Oktyabrsky District was one of the first industrial uses of the technology in Orenburg Oblast.