Method of estimation of annual risk from breaks, fires and explosions on the basis of state graphs in electrolysis plants

A method is presented for estimating the possible annual risk that a hydrogen superstructure at a nuclear power plant (NPP) may have in the production of explosive hydrogen. With the observance of safety rules in terms of receiving, storing, transporting and using hydrogen, it is possible to minimize the occurrence of fi re and explosion hazard situations on the hydrogen superstructure. Scheduled repair and overhauls with all diagnostics reduce emergencies and equipment failures in the same way. However, there is a likelihood for the equipment to be found in an abnormal state (breakdown, fi re and explosion) as a result of hydrogen leaks. Depressurization of equipment with leakage of explosive hydrogen in enclosed spaces concurrently with adverse attendant factors may lead to the destruction of the electrolysis plant due to fi re and explosion. With the help of the state graph, the probabilities of a failure of electrolysis equipment because of unplanned breakdowns and possible fi res or explosions indoors due to depressurization of equipment are estimated. To this effect, possible scenarios of breakdowns of the electrolyzer in one and two workshops are considered. In the calculations of the state graph, a system of linear equations was composed for steady-state values only. The calculations have shown that for a configuration involving two electrolysis plants, the possible annual risk would increase. Minimizing the annual risk can be achieved through boosting the capacity of the electrolysis plant still in operation by increasing its productivity in hydrogen and oxygen. The effect will only be achieved if the cost of electricity from nuclear power plants is kept within 0.81 rubles/(kW·h) with a peak electricity tariff at 3.5 rubles/(kW·h).

1. Safety rules for the production of hydrogen by electrolysis of water: safety regulations 03-598-03: approved. Gostehnadzor of Russia 06.06.03 [the Electronic resource]. Systems. Requirements: Adobe Acrobat Reader. URL: http://himenergo.ru/usr/file/PB%2003-598-03.pdf (date of circulation: June 28, 2018). (In Russ.)

2. Kirillov I. A., Kharitonov N. L., Sharafutdinov R. B., Khrennikov N. N. Ensuring hydrogen safety at nuclear power plants with water-cooled reactors installations. The current state of the problem. Nuclear and radiation safety 2017; 2(84): 26–37. (In Russ.)

3. Kuznetsov V. M., Ostretsov I. N., Khvostova M. S., Shingarkin M. A. The current state of safety of nuclear power plants, the prospects for the development of nuclear energy and conceptual issues of the development strategy for environmentally friendly nuclear energy. Safety in the technosphere 2014; 3(3): 60–73. (In Russ.)

4. Komarov Yu. A. Possibilities of a risk-based approach to the problem of improving the reliability and safety of nuclear power plants. Thermal power 2014; (10): 12–16. (In Russ.)

5. Puzach S. V., Lebedchenko O. S., Ischenko A. D., Fogilev I. S. The temporary mechanism of the impact of fire hazards on NPP personnel and comprehensive protection from them. Fire and explosion safety 2017; 26 (8): 15–24. (In Russ.)

6. Adamenkov A. K., Salnikov A. A., Veselova I. N., Ryasny S. I. Risk management of technological violations of nuclear power plants. Atomic Energy 2017; 123 (3): 123–127. (In Russ.)

7. Eliseeva M. A., Nikishin V. V. Applied problems of modeling technical risks of nuclear power plants. News SFU. Technical science 2015; 3 (164): 117–126. (In Russ.)

8. Guidelines for the assessment of fire risk for industrial enterprises. Moscow. 2006. [Electronic resource]. Systems. Requirements: Adobe Acrobat Reader. URL: http://files.stroyinf.ru/ Data2/1/4293830/4293830270.pdf (date of circulation: June 28, 2018). (In Russ.)

9. Bayramov A. N., Kirichkov V. S. Substantiation of layout decisions for combining NPPs with a hydrogen energy complex by the criterion of minimum dew. Works of Academenergo 2018; (1): 57–72.

10. Aminov R. Z., Khrustalev V. A., Portyankin A. V. Explosion-risk in nuclear power plants with hydrogen superstructures. Analysis of the problem and solutions. // Proceedings of Akademenergo 2013; (3): 41–51. (In Russ.)

11. Aminov R. Z., Khrustalev V. A., Portyankin A. V. The effectiveness of power generating complexes constructed on the basic of nuclear power plants combined with additional sources of energy determined taking risk factors into account. Thermal Engineering 2015; 62(2): 130– 137. (In Eng.)