Implementation of Novel Evolutional Algorithm for 3-Dimensional Radiation Mapping and Gamma-Field Reconstruction within the Chormobyl Sareophagus  
[PERSON]  
1 Institute for Safety Problems of Nuclear Power Plants, NAS of Ukraine, Str. Kirova, 36-a, 07270 Chormobyl, Ukraine 12 Institute of Mathematical Machines and Systems Problems, NAS of Ukraine, Akademika Glushkova Ave., 42, 03187 Kyiv, Ukraine 2  
[PERSON]  
2 Institute of Mathematical Machines and Systems Problems, NAS of Ukraine, Akademika Glushkova Ave., 42, 03187 Kyiv, Ukraine 2  
[PERSON]  
1 Institute for Safety Problems of Nuclear Power Plants, NAS of Ukraine, Str. Kirova, 36-a, 07270 Chormobyl, Ukraine 1  
[PERSON]  
3 HH Wills Physics Laboratory, School of Physics, University of Bristol, Tyndall Avenue, Bristol BS8 1 TL, UK 3  
[PERSON]  
3 Department of Applied  
in an unstable state by its operators, with the chronology of events that subsequently occurred in the early hours of that day leading to the greatest ever nuclear accident and largest radioactive release event to occur at a nuclear power generation facility [1]. As a result, 237 people suffered Acute Radiation Sickness, with 31 of these dying during the three months immediately following the accident [2]. In addition, approximately 300,000 residents living near the Chornobyl site, mostly in the nearby town of Pripyat (constructed for Chornobyl's workers), were displaced from their homes. To mitigate against the consequences of the accident and prevent the further release of radioactive material into the local and global environments, the structure known as the \"shelter object\" (SO, or more informally, the \"sacrophagus\") for burying the Fourth Power Unit of the Chornobyl Nuclear Power Plant was rapidly erected around the crippled reactor the same year as the accident. The entire emergency response included debris removal from the ChNPP site, the construction of the enclosing sarcophagus, and clean-up activities within the surrounding area involving more than 500,000 personnel, termed \"liquidators\" [1]. At the time of construction, the design lifetime of the SO was estimated at 30 years [3]. Following the collapse of the USSR in 1992, the Government of Ukraine announced an international competition for projects and technical solutions for the transformation of the shelter object facility. In 1995, the President of Ukraine signed a memorandum of collaboration with leaders of the G7 group of leading industrialized countries, as well as the Commission of European Communities, to support Ukraine in its activities at Chornobyl. A core condition of this involvement was the shutdown of the other RBMK units at ChNPP that were still operational, despite the earlier accident at the neighboring reactor Unit 4. A year later, in December 1997, the Chornobyl Shelter Fund (CSF) was established with the purpose of funding the Shelter Implementation Plan (SIP). This multinational program was completed in 2020 with the construction and commissioning of the New Safe Confinement (NSC), the dome-shaped, environmentally sealed structure that attracted enormous global media coverage as it slowly slid into place to completely enclose reactor Unit 4 alongside the surrounding SO. Such a momentous engineering accomplishment ensured compliance with safety and operational requirements for the next 100 years, including during the planned decommissioning and dismantling of both reactor Unit 4 and the SO. However, delivery of the NSC is only an intermediate milestone in the multi-faceted and extensive journey to de-risk the considerable global hazard represented by Chornobyl. The program of fuel-containing material (FCM) removal and radioactive waste (RAW) processing, including its subsequent disposal in a RAW repository (whether near-surface or deep geological), needs to be completed within the operational lifetime of the NSC.