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[Ixion]

I think your information may be USA-centric. Most of the work in small reactors is coming from Europe and China (Russia being taken here as part of Europe).

In general they are leveraging naval technology.

The attraction of small reactors to Russia and China is obvious - they have vast distances and remote settlements. Supplying electricity is difficult. Fuel for conventional powerstations must be transported across great distance , or else cables run for equal distances in a most inhospitable climate.

Nuclear power design in the US has largely stagnated because of the political climate.

[k14]

I think your information may be USA-centric. Most of the work in small reactors is coming from Europe and China (Russia being taken here as part of Europe).

In general they are leveraging naval technology.

The attraction of small reactors to Russia and China is obvious - they have vast distances and remote settlements. Supplying electricity is difficult. Fuel for conventional powerstations must be transported across great distance , or else cables run for equal distances in a most inhospitable climate.

Nuclear power design in the US has largely stagnated because of the political climate.

Yeah from looking on wikipedia it seems that most around are in the 600-1200MW bracket but as you say there are smaller units coming along which disprove my theory.

But then it does indeed get back to the cost factor. I doubt any private company would put that much money into building one due to the inflexibility in starting and stopping them depending on market conditions. The repayment time would be very very long. That only leaves the government to build one and I won't hold my breath for that to happen.

[Jantar]

You are much mistaken. The great majority of reactors are far smaller than this. In fact 1300MW is the LARGEST common commercial size.

Techniatome in France supply "off the shelf" (not quite) modular reactors for power and heat in 100MW to 300MW sizes.

The Chinese NHR200 is a simple robust 200MW unit extensively used.

Russia has the VK300 (250MW) and a small version , the OKBM PWR (45 MW) designed to be mounted on a barge.

Chinergy is building now 195MW HTR-PM units in China.

Yes, Ixion, there are smaller modular units available, but you also need to look at the uses that they have. The Techniatome units are designed for maritime use (read nuclear submarines), as are most of the other smaller units. There is progress being made on a smaller sized commercial unit of around 250 MW which is designed as a throw away unit. The idea being that it would be built undeerground, and at the nd of its useful life, instead of a massively expensive decommissioning process, the unit would be de-fueled, de-watered, then simply buried.

Most modern commercial units are around the 1000 MW size, which as K14 pointed out, is too large for NZ. The Russian 250 MW are currently the smallest commercial units that potentially could be suitable for NZ.

There is however another issue with nuclear power in NZ that has nothing to do with radiation or economics, and little to do with reserve requirements. Nuclear power units, once they go critical, are only pratical when at 100% load. This is fine in large robust countries and continents where even a 1000 MW reactor is less than 1% of the total demand and the supply area is spread over a number of time zones. Here in New Zealand we only have one time zone. Most of the country get up at around the same time time each day, there is a morning peak demand, followed by an afternoon trough, then a large evening peak demand, and a very low overnight demand. Hydro plant, fast start gas turbines and older style thermal units can cope with this changing load pattern quite easily. More modern combined cycle plant struggles, and nuclear plant is totally unsuitable.

Even in today's situation it is difficult to manage load patterns with Otahuhu and Stratford combined cycle plant having minimum load setpoints that are difficult for the country's electricity supply to handle. Until our consumption grows and flattens, Nuclear is not a viable option. (more Calmocos anyone?).

[sAsLEX]

NP and Huntly used to be alot bigger didnt they K14/Jantar?

Cough . The station (450 megawatts) is designed to use either fuel oil or natural gas, which comes from your own bloody website in fact! cough

But I do relise the like of otahu have required the decom of half the units at NP

and your: The power station is capable of producing 432 megawatts of power from its four turbine generator units.
Again according to your website

And also wouldn't a supply contract for NUclear fuel be complete, ie I will buy three tonnes of fuel per year and you take the waste back with you.

[Jantar]

NP and Huntly used to be alot bigger didnt they K14/Jantar?

Cough . The station (450 megawatts) is designed to use either fuel oil or natural gas, which comes from your own bloody website in fact! cough

But I do relise the like of otahu have required the decom of half the units at NP

and your: The power station is capable of producing 432 megawatts of power from its four turbine generator units.
Again according to your website

And also wouldn't a supply contract for NUclear fuel be complete, ie I will buy three tonnes of fuel per year and you take the waste back with you.

NP (New Plymouth) has 3 units each capable of just over 100 MW and each of these can go down to a minimumof 45 MW. There is a 4th unit incapable of running and never likely to run again, and the 5th unit has already been de-commissioned. Huntly has 4 units, each of 250 MW, and each unit is capable of going down to a minimum of 80 MW.

As you correctly note Clyde is listed as being capable of 432 MW. It is actually capable of more than this, but is limited by resource consent conditions. But that is from 4 units, each one capable of only 116 MW.

The largest single unit in New Zealand is the Otahuhu station at around 370 MW, but even then it can reduce its load to 240 MW.

With Nukes, we are talking of a single unit that stays at full load all the time it is generating. And 240 MW is pretty small for a commercial nuke. I would hope that any contract for nuclear material would be complete, but I still maintain that New Zealand's physical electricity system is too small for nukes . It may change in the future, and I hope I live long enough to see it. I would love to watch the commissioning of a nuke station.

[Winston001]

Understand your point Jantar, but why can't we have a nuclear plant at say 600MW and Clyde, Roxburgh and Benmore just idling? Spill or hold the water, only run a couple of generators, and if the nuc drops off the grid spin up the idle hydro generators.

It might mean the nuc needs to be in Picton but its got to be somewhere.

[sAsLEX]

NP (New Plymouth) has 3 units each capable of just over 100 MW and each of these can go down to a minimumof 45 MW. There is a 4th unit incapable of running and never likely to run again, and the 5th unit has already been de-commissioned. Huntly has 4 units, each of 250 MW, and each unit is capable of going down to a minimum of 80 MW.

Yeah have watched the death of NP, mum and dad built it, dad stil goes in for his evening and day time naps and trademe.....

[k14]

Understand your point Jantar, but why can't we have a nuclear plant at say 600MW and Clyde, Roxburgh and Benmore just idling? Spill or hold the water, only run a couple of generators, and if the nuc drops off the grid spin up the idle hydro generators.

It might mean the nuc needs to be in Picton but its got to be somewhere.

Not quite as simple as that, apart from that fact that clyde and roxburgh are privately owned and (i doubt contact are ever going to build a nuke plant) you just can't justify spilling water willy nilly cause thats money straight down the drain as far as they are concerned. If you have 600MW idle right next to a nuke plant then how are you better off from before you built the plant?

If you want me to explain the way the reserve works a little more indepth then I don't mind but it will take me a while. It basically runs off each plants overload that it can put out for a short amount of time. Every plant has it but its only used in the event of a generator dropping off, so just having a complete idle plant isn't the sort of reserve we are talking about. It could make a small amount of sense if the fuel it uses costs alot of money but then there's other problems that arise.

[Jantar]

Understand your point Jantar, but why can't we have a nuclear plant at say 600MW and Clyde, Roxburgh and Benmore just idling? Spill or hold the water, only run a couple of generators, and if the nuc drops off the grid spin up the idle hydro generators.

It might mean the nuc needs to be in Picton but its got to be somewhere.

The reserve that we are talking about is what is known as PLSR (Partly Loaded Spinning Reserve). This is the difference between what a plant is actually geneerating, and what it is capable of generating. It also must be in the island at risk because the two islands are coupled by a DC link, not AC. All plant has a minimum load that it can run at. Below this minimum hydro turbines are likely to suffer cavitation damage, and thermal stations can have flame instability and HP drum issues. Most hydro plant has an operating minimum of 50% load. (ie a 100 MW generator has a minimum of 50 MW). Some stations can go lower like Maraetai, but others have a higher minimum.

However in general terms to have a 600 MW nuke on the system, we would also have to have 1200 MW of other connected plant generating at 600 MW, plus other plant that doesn't have any reserve capability, but cannot be shutdown due to technical or resource consent issues. At present if a 600 MW nuke was in the North Island, the minimum generation would be around 2300 MW, but this is higher than the overnight demand, so something has to give.

[thehollowmen]

Nuclear isn't an option for NZ (and no I'm not some greenie who has nightmares about Chernobyl). Our power infrastructure isn't big enough to be able to handle a nuclear station. Also the cost of building one is way too big for NZ to stomach.

I think a pebble pile reactor would work just fine here.

[Motu]

They are building a new 300 and something generator at Huntly at the moment.The problem at Huntly is what they can put back into the river,they can't get the temps over 25C,so in summer they have to cut back to one generator running at minimum,close to shutting down the whole plant.So with the new plan comes a cooling tower,what I take to be the cooling tower has been buiilt and tested - it's not a tower but the long low building you see out front with 11 big chimneys.There could be some issues when it gets going - on the test runs in the early morning it's a fog producer,you can't see the rest of the power station for the mist it puts out.

[sAsLEX]

They are building a new 300 and something generator at Huntly at the moment.The problem at Huntly is what they can put back into the river,they can't get the temps over 25C

Similar problems for all thermal stations pretty much. NP has the same problems. Dont understand why they cant though, New Zealand has hundreds of isolated hot spots due to thermal activity, heck you can cook your trout in the sand at certain points round Lak Taupo so whats wrong with a little warm water produced by man rather than nature?!

[TwoSeven]

You are much mistaken. The great majority of reactors are far smaller than this. In fact 1300MW is the LARGEST common commercial size.

You might find that smaller reactors are one off use models. There is a ratio between required size and output of a reactor.

Reactors only produce heat, not electricity - they require another plant to do the latter. To produce a certain amount of heat required to produce the steam used to generate lekky, takes a core of a certain size which requires a certain amount of fuel and area to handle the heavy water.

Nuclear power plants are now available as modular standard units. You don't have to design them, just buy and install. The suppliers will provide training for operators. And of course you don't need to refine uranium, you just buy fuel rods from your friendly (not quite local) supplier.

There is a big difference in calling in bob the builder to make a new barn and a specialist reactor building firm to commission a new reactor.

I doubt that 'training operators' is as easy as you make it sound. Its not like training people to work in a garment factory.

"Nuclear waste" has become a bogeyman word, largely devoid of meaning. It is used to cover anything related to the nuclear industry, from the tailings at the uranium mine sites, through to (literally) the dust vacuumed from the power house floors. At one site in the USA , great play was made of the volume of daily waste produced. Shock. Horror. Until it was discovered that the WHOLE of the "waste" was in fact the waste from the staff cafeteria, and the waste paper bins in the offices .

The only "nuclear waste" that we need worry about is the spent fuel. Assuming this IS waste, because of course modern reactors can recycle it (MOX reactors). Send back the spent fuel rods, and they are "recharged".

If you use a "throw away" design (most US reactors are throw away, and most of the hysteria comes from the US. Go figure), then waste fuel production will be about 20 cubic metres per 1000MW per year. It varies of course. This is around 150 tonnes. As Mr Pixie said, about the size of a small house. This is the figure for the fuel itself. Containment will make that much larger, depending on what you contain it in.

I suspect you may be a bit limited in your understanding of what 20 cubic meters of waste uranium actually is. Its not like disposing of 150 tonnes of sheep shyte. Also, you seem to be completely unaware exactly the range of items that do need to be disposed of. Ever wonder what happens to the radiation tags people wear ?

You may want to have a read thru this document to see whats invovled. Its about Sizewell B, the last reactor built in the UK.

Roughly speaking it costs about NZ$7b to build and took 13 years to be completed. Its operating costs are about nz$340m per year.