ML20135G739
| ML20135G739 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 05/14/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1992-001-00 | |
| Download: ML20135G739 (11) | |
Text
B-127 Fig. 8.37.
Electrical distribution system for Crystal Rivqr. 3 out of service. Both EDGs started and loaded as expected. The reactor tripped (rods inserted) because of loss of power to the control rod drive (CRD) motors. The reactor coolant pumps did not trip because nonsafeguards busses 3A and 3B were unaffected, and the turbine did not trip because a reactor trip setpoint had not been reached yet. When the operator pushed the manual reactor trip button, the CRD motor breakers and the turbine both tripped.
Post trip reactor coolant system (RCS) temperature was lower than expected because of the temporary mismatch between primary heat production and secondary beat remoYal. The reactor was effectively tripped when all the control rods were inserted and resulted in a sharp decrease in primary heat production. The turbine remained on-line for a brief period after the rods were inserted and was drawing 100% steam flow during this time. This resulted in more heat removal following the trip than would be normal. As a result post-trip RCS temperature was lower than expected.
LER NO: 302/92-001 and -002 Figure removed during SUNSI review.