Tornado Regime at the Belarus NPP and the Threshold Probability of Tornado Danger

Consideration of hazardous and especially hazardous hydrometeorological impacts in design of buildings and structures of nuclear power plants

“…However, taking into account high dangers of tornados and their impacts on NPPs, their threshold probability is assumed equal to 10 -7 /year per reactor [5,6]. Lightning impacts on NPP buildings, structures and infrastructure also have specific features.…”

“…In case of tornado impacts the non-project accident with radionuclides release is not always inevitable. This is due to the fact that according to the tornado zoning scheme of the ex-USSR territory the estimated characteristics of the maximum probable tornado with the NPP impact probability of 10 -7 /year can be relatively weak [5,6,10]. As for impacts of other hydrometeorological factors, their consideration shall be formally based not on the occurrence of the threshold probability of P 0 = 10 -4 /year, as it is provided for by federal regulations [4], but on the following condition:…”

Assessment of tornado hazard in the nuclear facilities siting areas

“…The need to take into con sid er ation the po ten tial im pact of tor na does on NF and their en gi neer ing protec tion de sign is based on the proba bil is tic cri te rion of tor nado haz ard [1,3,4,16]. This takes into ac count the sta tis ti cal data on the pas sage of tor na does of var i ous in ten si ties near the NF sites.…”

“…How ever, the con se quences of tor nado im pact on NF may not al ways in ev i ta bly lead to such an ac ci dent. This is be cause torna does pass ing through the NF sites with the P G prob abil ity can be rel a tively weak [16]. As a cri te rion for decid ing whether to take into ac count or dis re gard haz ard ous ex ter nal phe nom ena of nat u ral or i gin (includ ing tor na does), the Rus sian reg u la tory re quirements ap ply the thresh old prob a bil ity P 0 = 10 -4 per one re ac tor per year [1].…”

Determining safety criteria for reinforced concrete structures of power plants taking the example of a nuclear power plant with RBMK

“…In other words, the alerting criterion is the emergency criterion diminished by a value expected from specific impact (seismic shock, blast wave, falling aircraft, etc.) [6][7][8] For concrete structures, monitoring is carried out to control opening of cracks, rebar stress and, if need be, also structural material temperature and compressive loads inside concrete, focusing on stress in compressed rebar assuming they undergo deformation together [9]. Stress of rebar material and opening fissures are typically measured by means of string devices.…”