4 ms·
Most energy profit comes from externalizing the costs. Floating reactors would do that fantastically! Love the "sink and don't leak" requirement.
by bronson 8y ago
Most energy profit comes from externalizing the costs. Floating reactors would do that fantastically!
Love the "sink and don't leak" requirement.
- acidburnNSA 8y agoBetter stated: sink and don't leak because you are intimately linked to a near-infinite heat sink, and heating up/melting are a prerequisite to leaking.
- DoctorOetker 8y agothat doesn't discuss corrosion though, the ocean is full of salt, how many half-lives until corrosion prevents containment?
- acidburnNSA 8y agoThe ocean would take a while to corrode through a couple dozen cm of steel, especially in cold water. But you're right that eventual leakage is a concern. A viable design of this kind of system would have to come with a sink-safely-and-cool design fully engineered as well as a designed recovery process. In other words, it should be expected that a recovery and disposal operation will be required (even though it's unlikely to be needed). This system should be designed so the salvage/recovery operation is easy. Nuclear accidents generally worry about something called Large Early Release Frequency. Some of the most bioactive/dangerous fission products decay away in a few days. This kind of scenario completely eliminates those FPs from concern, though we do still have to worry about the longer-lived ones.
- DoctorOetker 8y agois that assuming steel at the same temperature as the surrounding salt still water, or assuming steel that is hotter than the constantly convecting stream of fresh salty water?
- acidburnNSA 8y agoThe way the heat transfer would work in this scenario would have small temperature gradients on the outermost layer of heat transfer because steel and water are good heat transfer mechanisms. This isn't hypothetical. This list may interest you: https://en.wikipedia.org/wiki/List_of_sunken_nuclear_submarines https://en.wikipedia.org/wiki/List_of_sunken_nuclear_submari...
- DoctorOetker 8y agoI wasn't asking about a list of sunken submarines?
- acidburnNSA 8y agoThey are scuttled floating nuclear reactors at the bottom of the sea. These are real-life examples very similar to the scenario you are inquiring about. They have not corroded away and released wholesale nuclear waste after many decades. If that's not relevant to your line of inquiry then I must be totally misunderstanding you.
- DoctorOetker 8y agoquoting myself, emphasis added: >... the ocean is full of salt, how many half-lives until corrosion prevents containment? quoting you: >They have not corroded away and released wholesale nuclear waste after many decades. If that's not relevant to your line of inquiry then I must be totally misunderstanding you. You don't misunderstand me, you purpousely misinterpret my questions so you can give easy answers...
- acidburnNSA 8y agoAh, I see what's going on here. Please review the HN guidelines. I-131 has an 8-day half-life and is the primary threat to populations in large early releases. The direct answer to your question for I-131 is at least 2,000 half-lives. Sr-90 and Cs-137 have 30-year half lives, so for them it's at least 2. As you surely know, the longer half-life nuclides release energy more slowly and are therefore less dangerous to biological systems. At the extreme, U-238 has a few billion year half-life and can be handled safely without shielding. In the scenario I'm painting, the reactor would be recovered from the sea within ~5 years so none of this matters. The corrosion will not fail the system within those 5 years. I do not propose to just leave any failed reactor down there indefinitely.