News
Publish date: July 13, 2001
Written by: Igor Kudrik
News
Russian design bureau Rubin answered to a number of Bellona’s questions regarding the safety around raising the Kursk. Rubin is responsible for the technical part of the operation on the Russian side.
Bellona welcomes the initiative of Rubin to start the dialogue, but wants to stress that there are still a lot of questions unanswered to get a clear picture of the safety for the whole operation.
Bellona has always underlined that the Kursk must be lifted, and the officials in Russia should hurry with the operation, but not rush.
Bellona agrees with Rubin that no major accident can happen while lifting the Kursk. At the same time should the operation fail, it is unlikely that the Kursk will ever be raised again.
The answers were forwarded to Bellona through the Russian Embassy in Oslo and published on the Russian official web site www.kursk.strana.ru.
Bellona: Slicing off the bow section of the submarine may lead to detonation of ammunition scatted around.
Rubin: The designers of the missile and torpedo weaponry together with the military research centres and the Navy have conducted evaluation of the safety issues involved while working with the fragments of the torpedoes.
As a result the designers of the weaponry prepared guidelines on how to provide the safety.
Bellona’s reply: The Rubin does not answer the question what kind of measures will be taken to ensure that no ammunition is hit when the divers are slicing off the bow part of the submarine. The designers can well guarantee the safety as they apparently did for the torpedoes, which exploded and sank the Kursk. Bellona still considers this part of the operation as the most hazardous. A new explosion may damage the submarine and its reactors blocking the further possibility of lifting it.
Bellona: Drilling of 26 holes in the hull of the submarine can damage its integrity.
Rubin: The grappling devices will be inserted into the inner hull (the strong hull) of the submarine in such way that it will hook on the solid frames of the submarine. The estimations conducted by Rubin show that the lifting will not be interrupted even if two of the hoists on the barge, which will pull the cables, go out of order.
Bellona’s reply: What will happen if three hoists go out of order? And how can one be sure that the grappling devices are fastened as they should inside the submarine, taking into consideration that everything will be going on at the depth of 108 meters.
Bellona: The submarine is partly deepened into the seabed. Tearing it off the seabed may cause submarine jerking, which may destroy the grappling devices and eventually damage further the hull.
Rubin: Mammoet Company evaluated the soundness assurance factors, approved by the Rubin design bureau. Increased loads on the grappling devices and the hull during the submarine tearing off the seabed, lifting and transportation were taken into consideration.
Specific loads of every stage of the operation were taken into consideration. For example, cohesion with the seabed, increasing the sum heave impact, is accounted of. Additional impacts of fastening the hull to the barge are taking into consideration. For each stage of the operation there is a factor fixed, considering dynamic increase of the load, in case of heavy sea.
Bellona’s reply: The Kursk is partly deepened into the seabed. The hoists should be advanced enough to jerk the 12,000 tonne submarine up and still co-ordinate the movement with high precision.
Bellona: Lifting the submarine by the grappling devices to the platform and its fixation may be complicated due to the weather conditions. There is a technical difficulty of the Kursk placing in the dry-dock and the submarine examination.
Rubin: Lifting of the Kursk submarine will be performed using 26 cables, each of them consists of 54 strands, woven of metal rods. Breaking strength of a strand accounts to 16 t. Soundness calculations for the load-carrying connexions showed more than twofold margin of safety, considering the submarine weight increase during tearing it off the seabed.
But to make assurance doubly sure, the Rubin design bureau will cooperate with the Academician Krylov central research institute to carry out several tests to check specific junctions of the load-carrying connexions in natural conditions, close to the extreme.
During the sea operation stage (especially during the submarine lifting and transportation) permanent monitoring of the operation conditions is carried out: strength of wind, height and period of heavy sea and other hydrometeorological parameters are checked. The operation will start only if there is a favorable forecast, concerning the critical parameters of the weather conditions. The adverse conditions forecast will suspend the operation; all the ships involved will be operated in the storm mode.
Placing the barge and the submarine fixed to its bottom, into the dock, will be carried out using intermediate pontoons, creating additional floatation of the barge and securing the requisite conditions for placing the Kursk into the dock. The submarine examination will be carried out in the dock by the Russian Defence Ministry’s special services, after the dock and the submarine are drained.
Bellona’s reply: Rubin gave no clear answer what will happen to the Kursk reactors after the submarine is in the dry-dock. A defuelling operation of any submarine is potentially dangerous. The reactors of the Kursk may be damaged. The shipyard in Roslyakovo, where is submarine will be placed, is located just 10 km from Murmansk, a city with population of 400,000.
Bellona: The main concern of the Bellona Foundation is security of the nuclear reactor emergency blockage system and possibility of the reactor’s damage during the operation.
Rubin: Basing on the last monitoring results, analyses and state estimates of the equipment and the reactor systems we have ascertained unambiguously the following:
Analysis of the possible events and worst-case situations during the lifting operation, showed that even in the unlikely case of the submarine missing during its transportation above the deepest area, followed by its drop, turning-over and hit the seabed, the impingement attack value would be several times less, than the impingement, the reactor facilities did stand during the explosions in the submarine. Construction of the mechanisms of the reactors control and protection system has devices, securing blockage of the control grids in the lower position. There is no possibility of their spontaneous move from the active zone, caused by applied shocks and the submarine’s turning-over.
Thus, during the Kursk lifting operation, any possibility of damage to the reactor facilities and the emergency blockage system, which might violate their safe condition, is excluded.
Bellona’s reply: All laid up submarines have their control grids welded in the extreme down positions in addition to the regular blockage devices. This is done in order to ensure that if a laid up submarine sinks and flips, there will be no start-up of the reactors. Therefore, Rubin’s answer to this effect cannot be considered as fully correct. There is a possibility of reactors’ start up and meltdown. It will, however, not lead to major releases of radioactivity as the reactors’ shielding is designed to withstand such scenario.
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