Evaluation of high temperature gas reactor for demanding cogeneration load follow

Abstract

Modular nuclear reactor systems are being developed around the world for new missions among which is cogeneration for industries and remote areas. Like existing fossil energy counterpart in these markets, a nuclear plant would need to demonstrate the feasibility of load follow including (1) the reliability to generate power and heat simultaneously and alone and (2) the flexibility to vary cogeneration rates concurrent to demand changes. This article reports the results of JAEA's evaluation on the high temperature gas reactor (HTGR) to perform these duties. The evaluation results in a plant design based on the materials and design codes developed with JAEA's operating test reactor and from additional equipment validation programs. The 600 MWt-HTGR plant generates electricity efficiently by gas turbine and 9008C heat by a topping heater. The heater couples via a heat transport loop to industrial facility that consumes the high temperature heat to yield heat product such as hydrogen fuel, steel, or chemical. Original control methods are proposed to automate transition between the load duties. Equipment challenges are addressed for severe operation conditions. Performance limits of cogeneration load following are quantified from the plant system simulation to a range of bounding events including a loss of either load and a rapid peaking of electricity.

Hazard analysis and safety assurance for the integration of nuclear reactors and thermochemical hydrogen plants

“…3. Some investigators recommended this option to approach load following and buffer the fluctuations of heat cogeneration for hydrogen production or an oil refinery through accurate coordination of a group of valves that control turbine speed and inlet temperature and pressure (Yan et al, 2012). This option depends on if the turbine can accommodate a large amount of surplus heat and the power grid has a margin for the upload.…”

“…This option depends on if the turbine can accommodate a large amount of surplus heat and the power grid has a margin for the upload. The maximum buffer capability of surplus heat in past studies (Yan et al, 2012) was about 170 MW th , which is equivalent to about 50 ton/day of hydrogen production according to Table 3. However, the surplus heat disposal requirement for thermochemical cycles is much higher in a shutdown operation for an industrial hydrogen production scale, as shown in Table 3.…”

“…Studies on small-scale dynamic fluctuations of the heat requirements of S-I thermochemical hydrogen production plants have been reported (Yan et al, 2012;Shin et al, 2013). Some investigators examined the hydrogen production plant as a heat sink, so the coupled nuclear and hydrogen production system would experience a loss-of-heat-sink (LOHS) if one of the hydrogen processes or equipment failed .…”

Study of an incrementally loaded multistage flash desalination system for optimum use of sensible waste heat from nuclear power plant

“…To continue the power generation over long term, reactor outlet coolant temperature is reduced to 850 °C by inserting the control rods in the core and adjusting flow control valves to increase core flow rate. The reference gives details of this load control operation. The end of the control operation enters the plant operating parameters to exactly those of the standalone power generation plant of GTHTR300.…”