Part of: Chernobyl accident , Nuclear Russia

MOSCOW/ SLAVUTCH, Ukraine – A “combination of negative factors” rather than excessive snowfall was the cause of the February 12 partial wall and roof collapse at Chernobyl’s infamous Reactor Unit 4, recent findings of two commissions that investigated the incident revealed. Notably, the risk of concrete slabs collapsing over the reactor halls of the defunct nuclear plant’s three other units had been discussed just one day earlier, on February 11, in Ukraine’s Slavutich. And Russia has three stations running Chernobyl-type reactors, RBMK-1000s – all three of similar or older ages and still in operation. How badly should Russia be concerned about its old stations’ safety?

Andrei Ozharovsky, Maria Kaminskaya, 03/03-2013

News that a portion of wall panels and roof collapsed at Unit 4 of Chernobyl Nuclear Power Plant (NPP) came on February 12. Just one day before, the possible risk of some of the upper structures caving in on the reactor buildings housing the station’s Units 1, 2, and 3 – which were not themselves damaged during the catastrophic explosion of April 26, 1986, but were shut down in subsequent years – was discussed at a public hearing in the Ukrainian town of Slavutich, 50 kilometers from Chernobyl.

On February 26, a report stating the findings of two commissions convened to look into the causes of the February 12 incident was released on Chernobyl NPP’s website(in Russian), saying, in particular (quoted in Bellona’s translation):

“Snow load on the roof of the turbine hall at axes 50-68 from Range A to Range B did not at the moment of the collapse exceed the values established in the project and operating documentation of [Chernobyl] NPP.”

Instead, the report said, a truss failure – precipitated by a “combination of negative factors,” detailed in the findings – may have caused the collapse of a fragment of roof and walls at Unit 4.

The partial roof and wall collapse at Reactor Unit 4

On February 12, Chernobyl NPP’s press service reported an “abnormal situation” at the plant (quoted here verbatim):

“12.02.13. Partial failure of the wall slabs and light roof of the Unit 4 Turbine Hall occurred at 14.03 above non-maintained premises on the level 28.00 meters in the axes 50-52 from range A to range B. The area of damage is about 600m². This construction is not critical structure of the ‘Shelter’ object.” Читати далі ANALYSIS: Roof collapse at Chernobyl: What does it mean for Russia’s aged Chernobyl-type reactors? →