Independent regulatory examination of radiation situation in the areas of spent nuclear fuel and radioactive wastes storage in the Russian far east

Cytogenetic analysis (buccal micronucleus cytome assay) of radioactive waste management workers

The Russian Federation is implementing a program for dismantling nuclear-powered submarines and nuclear service vessels decommissioned from the Navy. Program personnel may be exposed to mutagenic and carcinogenic factors, including ionizing radiation. Improved preclinical health diagnostics are desirable, for timely identification of health effects, optimization of preventive measures, and medical interventions. We used an improved version of the buccal micronucleus cytome assay (BMCyt) to conduct cytogenetic status assessment of 59 employees of the Far Eastern Center for Radioactive Waste Management (DalRAO). We observed a statistically significant increase in the frequency of buccal epithelial cells with cytogenetic abnormalities (2.31‰ versus 1.15‰) and a small decrease in the apoptotic index (42 % versus 44 %) in the exposure group vs. controls. An accumulation index of cytogenetic disorders (the ratio of cells with nuclear abnormalities to cells in apoptosis) was determined and significant differences were found between the exposure and control groups. The proposed approach is simple, non-invasive, and highly informative for monitoring the health status of personnel exposed to complex factors in the working environment.

Comprehensive environmental monitoring during remediation of a nuclear legacy site in the Far East of Russia

In compliance with the fundamentals of the government's policy on nuclear and radiation safety, Russia is continuing to implement its national program for decommissioning its nuclear legacy. Under this program, the State Atomic Energy Corporation, 'Rosatom', is carrying out decommissioning and remediation of the Navy's former shore technical bases (STBs) in the Russian Far East. Along with the 'old problems' accumulated during the operation of STBs in the past, new challenges arise because of the planned intensification of radioactive waste (RW) management on the site in the nearest future. The paper presents the results of comprehensive environmental monitoring at the site of temporary storage for spent nuclear fuel (SNF) and RW at Sysoeva Bay, located in Primorsky Krai. One of the site's features is the cross contamination of the environment with radioactive substances and nonradiological pollutants. The dominant radionuclides in the environmental media are¹³⁷Cs,⁹⁰Sr, and a minor contribution from⁶⁰Сo. The soil contamination with artificial radionuclides predominantly relates to the category of industrial waste with local areas classified as very low-level RWs. The contamination penetrated the underground water via migration from the damaged SNF and RW storage facilities. Along with cesium and strontium radionuclides, widespread groundwater pollution with heavy metals (I-III hazardous classes), including Be and As, was revealed. Moreover, the exceedance of permissible levels of Cd reaches 1000 times, and that of radionuclides (⁹⁰Sr)reaches 50 times. It dictates the necessity to improve the environmental impact assessment by accounting for the nonradiological pollutants in monitoring design. The radiological conditions in the residential area are characterized by the regional background levels. The average annual effective dose of public exposure due to artificial sources does not exceed 40µSv.