Discussion Overview
The discussion centers on the survivability of Westinghouse 3-loop pressurized water reactors (PWRs) during a total blackout, particularly in the context of the North Anna incident. Participants explore the water volume of the secondary side of steam generators and the implications for maintaining operations without external power.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- Some participants inquire about the water volume of the secondary side of Westinghouse 3-loop PWR steam generators to estimate blackout survivability.
- There is a mention of the North Anna incident, where the plant lost off-site power and both units shut down, prompting interest in how long the plants could survive by boiling off water from the steam generators.
- One participant notes that PWR steam generators can boil dry in minutes if feedwater flow is lost, emphasizing the urgency of the situation during a blackout.
- Another participant suggests that if the steam generators are similar to those at Ringhals 4, the secondary side inventory could provide sufficient water for approximately 1.5 hours after a scram, contingent on the accuracy of their figures.
- It is mentioned that North Anna has a steam-powered pump and a station blackout diesel, which may mitigate the risks associated with a total electrical power failure.
Areas of Agreement / Disagreement
Participants express varying levels of concern regarding the survivability of the reactors during a blackout, with some suggesting that auxiliary systems may alleviate potential issues, while others focus on the critical nature of feedwater flow loss. No consensus is reached on the exact implications or effectiveness of the auxiliary systems.
Contextual Notes
Participants rely on specific figures and assumptions regarding water volumes and operational capabilities, which may vary based on reactor design and conditions. The discussion does not resolve the uncertainties surrounding the exact survivability duration during a blackout.