Survival from Canadian Seaplane Water Accidents: 1995 to 2019

INTRODUCTION: Each year in Canada, there are a number of pilots and passengers who die in seaplane water accidents. A study examining the human factors and fatality rates associated with these accidents was conducted. METHODS: Seaplane water accident investigations by the Transportation Safety Board of Canada (TSB) between 1995 and 2019 were reviewed. RESULTS: There were 487 accidents involving 1144 occupants (487 pilots, 657 passengers). There were less than 15 s warning in 86% of cases. There were 60 pilots and 88 passengers who dieda survival rate of 87%. Drowning, trapped within the cabin was the principal cause of death (54%). Loss of control on landing, wheels down landings, and other landing problems (49%) were the principal causes of the accidents and 77% of the fatalities occurred in this group. These arose because the pilot(s) misjudged wind, waves, and glassy water. Over 50% of seaplanes inverted and 10% floated briefly then sank, resulting in the highest percentage of fatalities. Wearing the seat harness incorrectly, injury, in-rushing water, and inability to locate and operate exit mechanisms (including rescuers inability to open the exits external to the fuselage) all contributed to the fatalities. Life jackets would have been of benefit in several cases. Of the accidents, 57% were private flights. CONCLUSIONS: Passengers require a thorough preflight briefing, life jackets should be worn by all pilots and passengers, and private and commercial pilots should receive Underwater Egress Training. MacDonald C, Brooks C, McGowan R. Survival from Canadian seaplane water accidents: 1995 to 2019. Aerosp Med Hum Perform. 2021; 92(10):798805.

Transient Analysis of Dedicated Pressure Relief Valve Under High-Pressure Condition in Severe Accident for Tianwan 56 Nuclear Power Plant

In the management of severe accident of nuclear reactor, the pressure relief of reactor coolant system (RCS) is an important mitigation measure to prevent high pressure core melt (HPCM). In the safety system improvement of Tianwan56 nuclear power plant, the optimization measure of adding the dedicated pressure relief valve (DPRV) for severe accident were adopted. This improvement allows the reactor to release the pressure of RCS before the reactor vessel being damaged to mitigate the consequence of reactor melt accident under high-pressure condition. Based on the analysis of severe accident sequences, the total loss of feed water accident is confirmed to cover the various severe accident consequences which may lead to HPCM accident. This paper studied the transient characteristics of total loss of feed water accident sequences, and the factors such as valve opening delay on the operating temperature of the valve were researched. Finally, the representative and envelope operating condition of DPRV under severe accident was clarified. Besides, the temperature curve of fluid passing through the valve and the maximum temperature the valve experienced were obtained. This research provides the valuable and indispensable basis to the operability and integrity analysis of DPRV in severe accident.

Loss of Feed Water Accident in an Integral Pressurized Water Reactor (IPWR)

In this paper research has been carried out on Loss of Feed Water Accident (LOFW) scenario of the Integral Pressurized Water Reactor ( IPWR) under two circumstances by the use of thermal hydraulic system code i.e Relap5/Mod3.4. In the first one, Passive Residual Heat Removal System (PRHRS) which is designed to absorb core residual heat in case of transient conditions is included which has the function of operating under the accident vulnerabilities. Concerning with the second case i.e without the use of PRHRS rather a tank of water which has the capacity of about 8% of the total feed water supply and is operated under accident scenario is considered. Taken into account these conditions,first the nodalization diagram of the two cases have been figured out then according to the LOFW accident time event scenario use the Relap5 code to simulate the accident. Finally the graphical explanation (separately) of the two cases with graphical approach as well as the conclusion is given at the end.