I have advocated and lobbied for a bare bones Lftr core whose interface to the old coal fired plant generator is precisely matched through the use of a molten salt interface comprised as follows: Sodium Nitrate NaNO3 60 % Potassium Nitrate KNO3 40 %. This salt mix can support a maximum salt temperature of 550C.
All the components of the old coal fired power plant are maintained except the coal fired boilers. There are two molten salt storage tanks provided, a cold tank and a hot tank, see diagram below. The cold tank provides the input molten salt feed into the Lftr; the hot tank stores the heat output interface of the Lftr. The coal fired boilers are replaced by a steam generator located inside the hot molten salt tank, see the diagram below.
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Water runs through the piping of the steam generator that converts the water to super heated steam compatible with the exact temperature and flow rate specifications required by the existing turboelectric generator sets that were supported by the old coal fired boiler house.
The molten salt interface provides the flexibility to match the heat flow rate, pressure, and temperature specifications of the existing coal fired plants generator sets. The hot molten salt storage tank receives either hot salt from the Lftr or cold salt from the cold salt tank to moderate the temperature of the super heated steam fed to the turboelectric generators
This approach will be the most attractive and economic repowering of existing coal fired coal facilities. There are a large number of these brand new plants recently placed in service throughout the world which have cost billions to construct. The utilities and governments who have made this large investment will look to recapture as much of it as possible.
The cost of such and molten salt/Lftr approach for a large coal fired plant repowering will be less then $100 million; this is far less the any CCS retrofit cost.
Can I come back to this topic, now that we have workable designs for MSRs, which are targetting a steam temperature of 600C.
The steam turbines sold for current nuclear plants are low temperature variants, so when looking for steam turbines we look at the supercritical ones designed for coal plants.
Is it feasible to retroft a MSR to a coal plant?
Are there newish coal plants that can be shut down? Coal plants are closing in the UK, but I'm not sure if the steam turbines are modern and new enough. The Netherlands and Germany have some brand new coal plants (http://www.climatechangenews.com/2016/1 ... -in-value/
) , and in the Netherlands at least they recognise this is not a long term solution. It could be that in the UK, by the time MSRs are available, the coal plants and their turbines will have demolished.
Between 2007 and 2012 the high and low pressure turbines were replaced by Siemens in a £100 million programme
If that covers 4GW - that is a very, very low price.
Though some components do get moved - this got "salvaged" from Didcot power station:http://www.dailymail.co.uk/news/article ... -4mph.html
Does it make sense to move second hand steam turbines?
If a typical steam turbine is 750MW, would it make sense to attach three - for the sake of argument, Thorcon - units?
I'm trying to evaluate future cost trends in UK nuclear, from Hinkley C at £92.50/MWh (2012 prices), down via AP1000, Hualong Ones, and on to MSRs. What would be the cost benefit of retrofitting?
Moltex's cost study claimed $1000/KW capex for the nuclear island, and $1,000 for the steam island, plus site specific costs. With the site specific costs and the steam island taken care of, that should be a halving of capital costs.
Coming back to the Netherlands as an example, would it be nice to retrofit this place?:http://www.rwe.com/web/cms/en/1772148/r ... wer-plant/
(Thorcon guys: Drool over that harbour! - Bring the nuclear island in on a barge and couple up! )