586 



A full-scale research program was carried out on a second expedition on several ships from 

 April to September 1991. Two Mir deep-water manned submersibles were outfitted with standard 

 dosimetric instruments and specially developed radiometric apparatus. The submersibles delivered 

 special cartridges with selective sorbents to capture certain radionuclides to the NS and recovered 

 them. Between August 23 and 31, 1991, both submersibles dived to the Komsomolets simultane- 

 ously for a total time of 66 hours 3 1 minutes. Thirty-two water and soil samples were taken im- 

 mediately alongside the NS's hull. The results of analyses obtained by January 1992 showed that 

 although the primary loop of the reactor was not watertight, the release of radionuclides was ex- 

 tremely low C^'Cs concentrations not over 10 pCi/1). 



It was learned that the upper part of the pressure hull in the area of the forward compart- 

 ments is damaged. It was also found that the doors of the torpedo tubes are open and seawater is 

 in contact with the bodies of the missile torpedoes. The casings of the NWH's have lost their 

 seals, and active warhead materials are in contact with seawater. 



A third expedition to the Komsomolets was conducted from May 7 to 18, 1992 aboard the 

 RA' Akademik Mslislav Keldysh and the IW Ivan Knizenshtem. Submersibles performed six 

 dives to the Komsomolets and to a rescue chamber discovered to have surfaced 300 meters away. 



Even the second expedition noted that the NS's hull had sunk into the mud relative to its base 

 plane at least 2.5 meters at the bow and up to 4.5 meters at the stem. In 1992, noticeable changes 

 were found compared to 1 99 1 . Hull encrustation by living organisms was less noticeable than in 

 August 1991, evidently due to seasonal variation. 



The pressure hull had significantly more damage in the bow than had been recorded in 1991 

 videotapes. Along the port side, in the area of the bulkhead between Compartments I and 11, a 

 transverse crack about 2 meters long and up to 50 mm wide was discovered. Along the same port 

 side of the pressure hull, a long longitudinal crack had appeared, approximately 30 mm wide 

 along nearly its entire length, and in some areas the crack's opening had reached 400 mm. In the 

 upper part of the pressure hull of Compartment II, along the port side near the attachment of an 

 emergency flotation buoy, the damage comprises a crack at least three meters long and up to 300 

 m wide. A noticeable increase in the amount of corrosion products (ferric oxide) within torpedo 

 tube 2 has been recorded. 



The predicted entry of small quantities of '"Cs into the seawater, first recorded in 1991, was 

 confirmed. The maximum cesium concentration near the NS was 180 Bq/m', and it averaged — on 

 the deck above the reactor compartment — 29.6 Bq/m^ (the allowable concentration of "'Cs in 

 drinking water is 550,000 Bq/m^). Although the official report states that analyses of water sam- 

 ples, bottom sediments and selective sorbents did not detect ^^'Pu release from the NWH's into 

 the environment in 1992, other data indicate that such releases have already been observed, albeit 

 so far not in dangerous amounts [32]. 



Inspection of the area around the Komsomolets disclosed local irregularities in the distribu- 

 tion of natural and artificial (technogenic) radionuclides in bottom sediments. Areas with some- 

 what elevated but not ecologically hazardous radionuclide concentrations have an area on the or- 

 der of tens of m^, located at distances of tens of kilometers from the NS. At present, the area's 

 complex hydrology (currents up to 1.5 m/s) and geomorphology do not permit an unambiguous 

 link to be drawn between the presence of irregularities in technogenic radionuclides and their re- 

 lease from the Komsomolets. 



Turning to predictions, we can note that it is rather favorable for reactor radionuclides and no 

 significant change in the marine environment should be expected in the inunediate fiiture. 



The radioecological situation regarding the plutonium component of the NWH's is more 



44 



