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+ - Nasa validates 'impossible' space drive->

Submitted by schwit1
schwit1 (797399) writes "Nasa is a major player in space science, so when a team from the agency this week presents evidence that "impossible" microwave thrusters seem to work, something strange is definitely going on. Either the results are completely wrong, or Nasa has confirmed a major breakthrough in space propulsion.

A working microwave thruster would radically cut the cost of satellites and space stations and extend their working life, drive deep-space missions, and take astronauts to Mars in weeks rather than months. In hindsight, it may turn out to be another great British invention that someone else turned into a success."

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Comment: Re:already done (Score 1) 132

Another key issue is not grouping all of the backup generators on the sea facing side of the reactor with an inadequate sea wall was a disaster waiting to happen.

Exactly my point, the plant should never have been placed where it could get hit by a tsunami, because it was not designed to withstand one. Had it been designed to withstand one, you would see a lot of differences, including layout of DGs and alternate sources above tsunami level. Improperly assessing the potential event was a failure of the regulator, and the constructor/owner as well.

Comment: Re:already done (Score 1) 132

On that last DG failure item, the point was that with multiple units right next to each other, each with multiple DGs, if the DGs for a unit failed, they could, in a reasonably short time, use supply from another unit's DG (that assumes the site was not destroyed by a tsunami, of course). You are correct, a source of power beyond the batteries is required to be available within a certain period of time. That period of time ranges from several hours to a few days, depending on the specific plant design.

Comment: Re:Stylized (Score 1) 132

Thanks for the correction. I mis-read the statements and I was wrong on that one. I got thrown off by the sudden switch from a discussion of external events to this topic which really isn't external events. I admit when I am incorrect and appreciate your clarification.

Still, be careful with the terminology of 'accident' and 'near miss' and the statistics behind them, as they get applied and represented in a very inconsistent manner by the anti-nuke lobby.

Comment: Re:already done (Score 1) 132

Agreed. Japan is a high seismic activity area and should have set higher requirements to start with, just as they should have never assumed a massive tsunami would not happen when its clear that it could based on the geology of the area and the type of coastline. Raising the minimum requires going back and re-analyzing to see if the design is still adequate and making modifications where it isn't, costly to do after the fact.

Comment: Re:already done (Score 1) 132

I think you did not read it, because it does not say "the plant survived an earthquake undamaged". So, you are resorting to changing my words so you can play a game of "gotcha", and you have gone down that path because your arguments were failing.

Please just stop now while you are behind.

Comment: Re:already done (Score 1) 132

The plant was not designed to operate when inundated by water, it was not designed to withstand a tsunami of this magnitude, it was assumed a tsunami would never breach the protective wall and reach the plant, therefore, simple things like protecting the structures from the forces of the tsunami, and waterproofing all of the ducts, vents, doors, etc with controls over when and how long they can be open, were never in place.

Even with diesel failures at a unit, it could still have been safely shut down had the tsunami not hit. One option could have been borrowing power from another unit, but that would not necessarily be required. Diesels are very reliable machines that are tested on a regular basis. Adding a third does not improve the situation as much as you may think, because if two fail at the same time, its more likely a common cause than a different one, and the third diesel would stand a good chance of suffering that common cause as well. That is where testing, maintenance and reliability programs become very important. Also, having diverse means to achieve a safe state is also key.

The key is not placing a plant that cannot withstand a tsunami where it can be hit by one, because designing to withstand a tsunami suddenly inundating the site it really not practical.

Comment: Re:already done (Score 1) 132

First, there were more than one unit that all met essentially the same fate from the tsunami, it was not just one unit, and each unit has multiple safety systems that are designed to complete their mission even if one fails, as the assumption is always that something will go wrong. There were plenty of operable cooling components in place to shut down the plant after the earthquake. Not so after the tsunami.

Comment: Re:already done (Score 2) 132

You claimed the plant was not at all affected by the earthquake, which is wrong.

I never said the plant was not at all affected, that is another fabrication by you. The safety systems, those designed to operate after such an event, were quite capable of safety shutting down the plant after the quake. They were not capable after the tsunami hit.

Comment: Re:already done (Score 2) 132

Outside power is not required to shut the plant down. There nearby plants, the ones right next door, the ones not hit by the tsunami, also lost power but shut down just fine. The Fukushima Daiichi plants were in the process of shutting down after the quake and before the tsunami, even though offsite power was lost. The emergency diesel generators had started and the units were just fine to shut down. Had the tsunami not hit, regardless of the quake, you would never have heard of Fukushima Daiichi, just like you probably can't name any of the units that survived the severe earthquake without googling.

What this country needs is a good five cent microcomputer.

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