Station blackout at Browns Ferry Unit One - Oak Ridge National ...

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Comparison of FSAR and BWR-LACP calculations of drywell temperature
was performed for the "Loss of All AC Power" results shown on Fig.
Q.14.2-1 of the BFNP FSAR. Plant conditions assumed by the FSAR calcula
tions include:
1. Initial power = 100%.
2. Loss of all AC power at time = 0.
3. Drywell perfectly insulated on outside.
4. Heat capacity of interior equipment and structures is negligible.
5. Energy input from primary surfaces is initially 2000 kW.
6. Heat transfer coefficient between atmosphere and wall is 11.36
w/m**2°C (2 Btu/h ft2 °F) without steam condensation.
7. Drywell coolers lost at time = 0 and not restarted.
8. Steam leak = 0
The conditions assumed for this analysis are of the same order as those
assumed for the "Normal Recovery" part of the Station Blackout as dis
cussed in this report. Comparisons of various predictions of drywell
atmosphere temperature to the FSAR result are shown on Fig. 4.4. The drywell
temperature climbs rapidly during the first 5 to 10 min, before heat