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ABSTRACT
Pool-type low-temperature heating reactor (PLTHR) has attracted considerable attention throughout the world due to its low operating parameters and satisfactory inherent safety in district heating. Exploring the dynamic performance of PLTHR is a prerequisite for designing control systems and developing operation strategies. Until now, the dynamic performance of the district heating system using a 400 MW pool-type low-temperature heating reactor (DHR-400) has not been fully discussed. Based on APROS software, a precise dynamic model for DHR-400 is constructed in this paper. The dynamic responses of DHR-400 under five external variables such as control rod reactivity, first loop flow rate, second loop flow rate, third loop flow rate, and return temperature at the third loop are investigated. The results revealed that the core power variation is not linear with the flow rate variation at the three loops. Core power variations are −16.27, −14.04, and −20.96 MW with a 30% reduction in flow rate at the first loop, the second loop, and the third loop, respectively. Considering safe operation, when there are minor fluctuations in the heating demand, the core power regulation method by adjusting the third loop’s flow rate should be given priority without altering the position of the control rods.
Nomenclature
| Abbreviations | = | |
| DHR-400 | = | 400 MW pool-type low-temperature heating reactor |
| PLTHR | = | Pool-type low-temperature heating reactor |
| FHE | = | First heat exchanger |
| PID | = | Proportional-Integral-Derivative Controller |
| RP | = | Rated power |
| SHE | = | Second heat exchanger |
| SLTHR | = | Shell-type low-temperature heating reactor |
| Symbols | = | |
| Gf | = | Flow rate at the first loop, kg/s |
| Gfr | = | Rated flow rate at the first loop, kg/s |
| Gs | = | Flow rate at the second loop, kg/s |
| Gsr | = | Rated flow rate at the second loop, kg/s |
| Gt | = | Flow rate at the third loop, kg/s |
| Gtr | = | Rated flow rate at the third loop, kg/s |
| nr | = | Relative neutron flux density |
| P | = | Real core power at a certain time t after a disturbance occurs, MW |
| Pi | = | Initial reactor core power, MW |
| PFHE | = | Power of FHE, MW |
| Prc | = | Reactor core power, MW |
| PSHE | = | Power of SHE, MW |
| Pst | = | Final stable power of the reactor core after a disturbance occurs, MW |
| Tac | = | Average temperature of the coolant inside the core, ℃ |
| Tcin | = | Inlet temperature at the core, ℃ |
| Tcout | = | Outlet temperature at the core, ℃ |
| Ttr | = | Return temperature at the third loop, ℃ |
| Trtr | = | Rated return temperature at the third loop, ℃ |
| ts | = | Settle time, s |
| Tts | = | Supply temperature at the third loop, ℃ |
| Greek symbols | = | |
| ρ | = | Reactivity induced by control rods, pcm |
Disclosure statement
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.