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Comment: Re:$100 billion for 150 miles? (Score 1) 189

by nojayuk (#49527041) Attached to: Maglev Train Exceeds 600km/h For World Record

The Nishi Seto expressway doesn't stop in Onomichi, it just dives off the mainland to Mukaishima and beyond via the bridges and doesn't bring much to Onomichi itself apart from bicycle rentals for tourists. Mihara just along the coast is a much more active ferry port with regular sailings to various islands, and that's why Mihara gets Hikari shinkansens whereas Onomichi only gets the stopping Kodama service. Mihara's shinkansen station is integrated with the local JR line station down by the docks, a short walk to the ferry port. I use the Mihara station to get to and from Hiroshima when I'm staying in Onomichi (as I will be again in a few weeks time).

The Onomichi ferries are still in operation. 100 yen to cross the Pacific, what a bargain!

The company you mentioned, was that the Hitachi-Zosen shipyard on Mukaijima next to the bridges? I've been told it used POW slave labour during WWII.

Comment: Re:$100 billion for 150 miles? (Score 1) 189

by nojayuk (#49526369) Attached to: Maglev Train Exceeds 600km/h For World Record

It's sort of self-fulfilling that the bigger cities like Osaka, Hiroshima etc. have shinkensen stations near their centres because all the trains stop there. Since they slow down a lot before they stop the tracks can curve more than out in the countryside where the top speeds are achieved and straight-line no-grade track is required.

That's not to say the shinkansens slow down to an Amtrak crawl entering the big cities. The shinkansen tracks have blast walls where they pass through built-up areas as they're still going at over 150km/h and they'd blow out windows and knock over small children from the shockwave otherwise.

Other shinkansen stations have a pass-through track between the platforms where the expresses like the Nozomi run while the slower Hikari and Kodamas wait to let them pass. Many of those stations are some distance from the city centres. It's kind of fun to see the expresses blast through the stations at speed...

Comment: Re:$100 billion for 150 miles? (Score 1) 189

by nojayuk (#49526077) Attached to: Maglev Train Exceeds 600km/h For World Record

I love Onomichi, it's a little port town nowhere in particular but it's a great relief from the concrete of Tokyo and Osaka. They film TV shows and movies there quite often when the producers need a town away from the big cities as a backdrop and it's even appeared in anime -- the series "Kamichu!" was set there. It has quite a few old rather run-down temples and shrines, not manicured and all shiny like Kyoto's ones. There are few if any foreign tourists too since no-one's outside Japan has ever heard of it.

Onomichi got a shinkansen station mostly because of local politics and pork-barreling when the Sanyo line was being laid out but it only gets a Kodama stopping service, the quicker Hikari and Nozomi trains just barrel through on their way to Hiroshima or Osaka.

Comment: Re:$100 billion for 150 miles? (Score 1) 189

by nojayuk (#49523875) Attached to: Maglev Train Exceeds 600km/h For World Record

Yep. The first time I tried to visit Kurashiki (mistyped the name in my original post, sorry), I got out at the shinkansen station and started walking towards what I though was the town centre (it's a tourist attraction, an old-style Japanese town with canals and such). Six hours later, hopelessly lost, footsore and out of water I got a taxi back to the shinkansen station and went back to my hotel in Onomichi. Second time I visited I got on the local train to Kurashiki proper from Shin-Kurashiki.

Shin-Onomichi is up in the hills behind the town itself whereas the JR station is pretty much on the waterfront down by the shore. I'll be there in a few weeks celebrating my birthday with Onomichi-style ramen but I usually get a local-line train to Onomichi from the Fukayama or Mihara shinkansen stations, depending on which direction I'm travelling in.

Comment: Re:$100 billion for 150 miles? (Score 2) 189

by nojayuk (#49523673) Attached to: Maglev Train Exceeds 600km/h For World Record

In Japan the Shinkansen stations are connected to or part of a larger general network station.

Actually no. Many shinkansen stations are adjacent to mainline railway stations in Japan but not all of them. Shinkansens run on their own separate railtracks on a separate network to the mainline trains. They have to, they're standard gauge (4ft 8 1/2 inches) whereas Japan's regular rail network is nearly all a smaller gauge, 3ft 6 inches.

Shinkansen stations such as Shin-Onomichi and Shin-Karashiki serve smaller cities and are some distance from the town centres and their regular railway stations as it would have been inconvenient to route the shinkansen track into those city centres.

Comment: Re:Olde-timey carbon fuel (Score 1) 365

by nojayuk (#49469653) Attached to: Can Civilization Reboot Without Fossil Fuels?

Yes, any cellulose material will do pretty much. The best charcoal is from hardwoods or dense-fibred cellulose and that, unfortunately, takes time to grow. Crushing, compressing and drying the feedstock before turning it into charcoal would help but it's more work.

The most common source of charcoal in Britain and generally in Europe was hazel and beech which could be coppiced without cutting down the trees and waiting for them to regrow.

Comment: Olde-timey carbon fuel (Score 5, Interesting) 365

by nojayuk (#49469201) Attached to: Can Civilization Reboot Without Fossil Fuels?

The classic multipurpose "biodeiesel" of old was charcoal, a renewable source of fuel for high-temperature furnaces suitable for making iron and high-quality steel. Its use today is pretty much limited to barbeques and re-enactment smithing but a post-apocalyptic world could easily return to it for such purposes.

Trees don't grow quickly and the production of charcoal was never enough to sustain the demands for process heat for a society even a tenth as large as it is today but assuming a massive post-apocalyptic die-back and natural reforestation it would probably work. It doesn't require any process plant or chemicals to produce after all.

Lower-temperature needs such as locomotive and boiler steam could be met with simple logging of reforested areas without the extra step of turning wood into charcoal.

Comment: Re:Actions have consequences. (Score 3, Interesting) 229

Actually China's nuclear arsenal is a fraction of the US and Russian arsenals. It's about the same size as France's (250 - 300 warheads) but China doesn't have a deployable ballistic missile submarine fleet to provide the sine qua non of the Big Boys, a guaranteed second-strike retaliatory capability. They're working on building that capability but it's not operational at the moment.

China has signed but not yet ratified the Comprehensive Test Ban Treaty (CTBT) but its last shot was in 1996 after 45 tests in total. The only other nation in the Big Five who has not ratified the CTBT is the US who stopped testing in 1992 after firing off over 1000 devices.

Comment: Re:Wrong Focus (Score 3, Insightful) 132

by nojayuk (#49365047) Attached to: SpaceX's New Combustion Technologies

A NTR requires the reactor core to be hotter than the exhaust gas stream/propellant in order to transfer heat to it. Anything over 4000 deg K, structures in the core are going to melt and that would be bad, and that limits how hot and how fast the exhaust will be.

Nuclear thermal is more efficient than chemical rockets but not that much more efficient. It can use readily available mass like cometary or asteroidal ice or gases like methane mined from Titan but if you have access to such sources then simple cryogenic fuel/oxidiser combos like LOX/LH2 produced from ice by solar-powered electrolytic plants are going to be easier to manage and less massive than a reactor-based rocket motor. In such a case the vacuum of space works to your advantage to keep the LOX and LH2 from boiling off too fast.

Comment: Re:Wrong Focus (Score 1) 132

by nojayuk (#49364771) Attached to: SpaceX's New Combustion Technologies

Don't forget the multi-megawatt radiators needed to provide a cold sink for those reactors. Chemical rocket engines dump heat into the exhaust gases but in a vacuum radiators have to be huge and heavy to get rid of significant amounts of heat from something like a nuclear reactor. They also have to be shaded from sunlight to stop them absorbing heat...

Comment: Re:SOLAR (Score 1) 148

by nojayuk (#49345051) Attached to: First Nuclear Power Plant Planned In Jordan

Nuclear propulsion reactors are quite a bit smaller than the current generation (no pun intended but I'll take what I can get) of PWRs and BWRs which typically start at 3GWt and can go up to as much as 5GWt (assuming the EPRs ever get finished and/or anyone commissions a full-scale ESBWR from Hitachi). Even the largest propulsion reactors like the Ford class CVNs at ca. 1GWt can be swung a lot faster as there's less fuel and heat to deal with. The very high fuel enrichment levels (RN Astute-class submersible cruisers use 90+% enrichment fuel in their Rolls Royce reactors) also helps as a major problem with swinging a low-enrichment PWR or BWR is the buildup of short-lived Xe-135 fission products in the fuel pellets. This isotope is very neutron-absorbent and causes problems controlling the the swing down and up again. It can be done and is done but it's not as simple as twiddling a dial on a control panel.

Comment: Re:SOLAR (Score 2) 148

by nojayuk (#49340287) Attached to: First Nuclear Power Plant Planned In Jordan

GenIIa reactors like the Russian VVER-1200 and the uprated French M310 designs can swing their output by 30% in fifteen minutes or so, given modern control systems and a few decades of experience in running such PWRs and BWRs. It doesn't happen often because nuclear fuel is so cheap and reducing power output doesn't save much money.

Comment: Re:2022? (Score 3, Informative) 148

by nojayuk (#49340231) Attached to: First Nuclear Power Plant Planned In Jordan

It depends if there's a production line for large components and a guaranteed market for future orders. The Chinese are rolling out 1GW reactors from breaking ground to grid connection over a period of about five years or so but they've got predictable orders of the large components needed for a reactor and teams of engineers who move from one site to the next as their particular tasks (pouring the basemat, building the containment, installing the reactor vessel etc.) on a given construction site are completed, they don't have to learn how to do it again from scratch every time. Rosatom is in the same position, building a number of reactors of similar design in Russia and around the world but also leveraging a turnkey operation capability, supplying fuel and taking away spent fuel for reprocessing and waste disposal which is very attractive to countries like Vietnam, Jordan and other Arab nations.

Ningde 3, a 1GW reactor on the central coast of China started construction with first concrete in January 2010 and achieved grid connection a couple of days ago, about 63 months later. Two more Chinese reactors of similar capacity are expected to come on line this year.

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