Prediction of temperature and water level in a spent fuel pit during loss of all AC power supplies

^†This is a translation of an article originally published in Japanese in Transactions of the Atomic Energy Society of Japan <http://dx.doi.org/10.3327/taesj.J11.050>. Taylor & Francis do not warrant the accuracy of the translation.

Figures & data

Figure 1. Conceptual diagram of a PWR spent fuel pit.

Figure 2. Evaporation heat fluxes calculated by Equations (1) and (2).

Figure 3. Increase of water temperature during the shutdown of cooling systems.

Figure 4. Heat transfer model for loss of all AC power supplies.

Table 1. Calculation conditions [5].

Initial conditions
Vw,0 (m^3)	Hw,0 (m)	Tw,0 (°C)	Ta,out (°C)	Tw,in (°C)
1390	11.5	30	10	10

Note: V_w,0: initial water volume (m³), H_w,0: initial water level (m), T_w,0: initial water temperature (°C), T_a,out: outdoor temperature (°C), and T_w,in: temperature of injected water (°C).

Figure 5. Transient behavior after loss of all AC power supplies (Unit 4 pool, intact building).

Figure 6. Transient behavior after loss of all AC power supplies (Unit 4 pool, damaged building).

Figure 7. Water level (Unit-4 pool, damaged building, 0.8 Q_D).

Figure 8. Transient behavior after loss of all AC power supplies (Unit 2 pool, intact building, without water injection).

Figure 9. Transient behavior after loss of all AC power supplies (Unit 2 pool, intact building, with water injection).

Figure 10. Effects of decay heat (Q_D) and evaporation heat flux (q_E) on water temperatures (Unit 2 pool).

Figure 11. Effects of decay heat (Q_D) and evaporation heat flux (q_E) (Unit 2 pool, 0.8 Q_D, 2.3 q_E).

Figure 12. Water temperatures (Unit 4 pool, damaged building, 0.8Q_D, 1.55q_E).

Figure 13. Comparison of evaporation heat fluxes.

TEPCO. Report on effects of the earthquake in the Northeastern Japan on nuclear facilities in the Fukushima Daiichi nuclear power station. The Tokyo Electric Power Company; September 2011. Japanese.

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