A good place to start is the lead article, 24 Hours at Fukushima. This article summarizes the events of the critical first 24 hours after the earthquake, with a focus on specific events and actions that seem like they represent learning opportunities.
The article has all sorts of fascinating details about the events of that day, such as the fact that it was hard to bring emergency equipment to the site when the roads were full of evacuations headed from the side; the observation that, after the earthquake but prior to the tsunami, an emergency cooling system was intentionally shut down because it was cooling the reactor too fast; the detail that, once power went out, electric security locks on building doors and fences had to be first broken before emergency equipment could be moved through them; and the observation that, when reactor 1 exploded, debris from the explosion ripped through the emergency backup power cable that had been installed to bring emergency power back to the plant.
And much, much more. There are so many small breakdowns, and decisions, and implications, that can be considered and thought about and studied.
The article notes that many of the subsequent problems arose from the fact that backup electrical power was lost, and could not be restored, and suggests several lessons that should be learned, including various ways to ensure that backup electrical power would be less likely to be lost, more likely to be subsequently restored, and perhaps even less likely to be needed; specifically, the article calls out 6 "lessons":
- LESSON 1: Emergency generators should be installed at high elevations or in watertight chambers.
- LESSON 2: If a cooling system is intended to operate without power, make sure all of its parts can be manipulated without power.
- LESSON 3: Keep power trucks on or very close to the power plant site.
- LESSON 4: Install independent and secure battery systems to power crucial instruments during emergencies
- LESSON 5: Ensure that catalytic hydrogen recombiners (power-free devices that turn dangerous hydrogen gas back into steam) are positioned at the tops of reactor buildings where gas would most likely collect.
- LESSON 6: Install power-free filters on vent lines to remove radio-active materials and allow for venting that won't harm nearby residents.
Still, the lessons seem well-meant and clearly point out starting points for the discussions to come about improvements and enhancements. I love lesson 2 in particular, as it points out one of those "obvious in hindsight" mistakes that clearly represents an opportunity for all operators in every such site to review their similar equipment and ensure that it doesn't suffer from the same design flaw.
Engineering is hard. Things happen that you didn't expect, and you have to study your mistakes, learn from them, explore alternatives, test systems, and revise, revise, revise. As the article notes, we've learned a great deal from the tragedy at Fukushima, and we need to continue to learn more.
I'm not a nuclear engineer, but I am immensely grateful for efforts such as this one, to help us interested lay-people try to come to grips with what happened, and why, and what does it mean, and how do we make it better in the future.
Certainly, it makes me more motivated to return to my own designs, and to study them, and test them, and continue to learn from my own failures and make my future work better. I recommend this article highly; I think you'll find it interesting and well worth your time.