Evidence from explosions in vessels divided into two compartments which are connected by a small opening, show that ignition in one can propagate into the other producing peak pressures and. Maximum pressures and rates of pressure rise resulting from gas explosions in isolated vessels can be calculated fairly accurately and so appropriate steps can be taken to design process equipment adequately. The problems associated with testing in the reactor containment environment are discussed, the development of the leak testing system described, a theoretical justification for the equipment is given and operational experience gained in several countries across Europe reponed. The system is fully compensated for the post loading temperature changes, and offers a substantial increase in sensitivity when compared to the Bourdon gauge. To overcome these problems, a system has been developed which uses a water manometer to measure the pressure drop. This results in gas pressure rises as the temperature of the flask increases following fuel loading. Historically, the test has been performed using a Bourdon gauge, however this presents two problems: (1) The insensitivity of the gauge results in long test times. The performance of the seals is tested by pressurising the space between the seals to approximately 7 bar (gauge) and observing the pressure. The flask lids are sealed using two concentric elastomer O-rings. The NTL Leak Testing System for Fuel Transpon Flasks has been developed to ensure the integrity of the lid sealing system used on NTL's fleet of ‘wet’ fuel transpon flasks prior to shipment.
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