Beyond-design—basis accidents

By analogy, the voluntary accidents of human origin are included here and dealt with in a similar way. 

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Storage and transportation of naval spent nuclear fuel engineering solutions and radiation consequences of beyond design-basis accidents, J. Problems of Nuclear Submarine Decommissioning, 2, 24-30 (in Russian). 

CEFR is pool-type reactor and the main vessel is divided into two parts. The upper part is called hot pool because it contains hot sodium whose temperature is 516 centigrade degree. The lower part is called cool pool because it contains cool sodium whose temperature is 360 centigrade degree. This accident is a BDBA (Beyond Design Basis Accident) in the Primary Safe Analysis Report of CEFR. Here are initial conditions,... 

At beyond design basis accidents 20rem 0,5 rem (on SPZ boundary)... 

Primary coolant components are placed inside the safeguard vessel and imder all designbasis accidents the possible release of radionuclides would be retained within the safeguard vessel. Only under beyond design-basis accidents when pressure exceeds the allowable limits the radioactive medium could be released from the safeguard vessel into the containment through the bubbling device. 

Under the accidents caused by primary coolant leak this gap is filled witii water thereby providing adequate heat removal from the reactor vessel. That excludes the probability of reactor vessel meltdown under postulated beyond design-basis accidents involving the core dryout. 

The function of the ROPS is to reduce the reactor pressure at the postulated beyond design basis accident related with a control system failure. The system consists of two parallel trains which are connected to the PZR through a single pipeline. Two trains are also combined to a single pipeline connected to the internal shielding tank. Each train is equipped with... 

Safety Strategy for Beyond Design-Basis Accidents... 

Beyond-Design-Basis Accident Avoids Radionuclide Release By Decay Heat Conduction To Ground... 

SSCs which are used in plant emergency operating procedures (EOPs) or are relied on to mitigate the consequences of transients or beyond design basis accidents. 

Design Basis Accidents, Beyond Design Basis Accidents, Severe Accidents (see Section 1-2 and Chapter 3). 

V Extremely Unlikely 10 >F All other accidents. Accidents too unlikely to be considered in the design basis. Some accidenfe in feis frequency category may be evaluated as beyond design basis accidents. 

Their implementation was also started at NPP in Ukraine. However, substantiation of the units safety performed before did not completely take into account necessity of the efficient analysis of operational experience, assessment of common cause failures (of natural and technogeneous origin) impact, analysis of beyond design basis accidents and development of the measures to manage them as well as a number of other provisions. 

PHARE 4.2.7.a/93 Project Beyond Design Basis Accident Analysis and Acident Management, Accident Management Study, Westinghouse Energy Systems Europe S.A., March 1998... 

Beyond design basis accidents are analysed for the following purposes ... 

TABLE 5. RBMK ACCEPTANCE CRITERIA FOR DESIGN BASIS AND BEYOND DESIGN BASIS ACCIDENTS... 

When using FR-bumer with a fuel, containing increased plutonium content, both Doppler - effect and SVRE value decrease. However, the Doppler - effect value decrease is in allowable limits, and besides reactor self-protection in some beyond design basis accidents improves. 

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