Seismic stability of a standalone glove box structure

• Glove box is a leak tight, safety related structure used for handling radiotoxic materials.
• To study the seismic performance of a freestanding glove box, extensive shake table testing has been carried out.
• Glove box maintained structural integrity and leak tightness up to design basis earthquake loading.
• Detailed three-dimensional finite element model of the structure is developed and analyzed by using direct time integration methods.
• Simplified numerical method is proposed and successfully applied, to quickly estimate sliding displacement and determine upper bounds for it.

In a nuclear fuel cycle facility, radiotoxic materials are being handled in freestanding leak tight enclosures called glove boxes (GBs). These glove boxes act as a primary confinement for the radiotoxic materials. Glove boxes are designed as per codal requirements for class I component. They are designed to withstand extreme level of earthquake loading with a return period of 10,000 years. To evaluate seismic performance of the glove box, there is a need to check the stability (sliding and overturning), structural integrity (stresses and strains) and leak tightness under earthquake loading. Extensive shake table experiments were conducted on a single standalone glove box. Actual laboratory conditions were simulated during testing to check the response.After extensive shake table testing, glove box structure was also analyzed using finite element (FE) software. Detailed three-dimensional model of glove box structure was developed and analyzed using nonlinear time history method. It was observed that finite element methods could be utilized to accurately predict dynamic response of glove box structure. This paper discusses the details and results of shake table testing and methodology used for modelling and analysing freestanding glove box structure under seismic loading. In addition, simplified numerical procedure, developed using energy conservation principle is applied to estimate approximate sliding displacement of the glove box.