Thursday, 12 November 2015

When "saving money" costs you two hundred fold more than you save.

I sometimes hear we can't afford to spend R&D money on MSRs. The best reply to that is we can't afford not to spend energy R&D.

85% of the world's reactors are PWRs, which operate with a thermodynamic efficiency of only 32% [only 32% of heat energy is converted to electricity]. MSRs can run at 750°C, giving a potential thermodynamic efficiency of up to 48%. Half as much again. Current power reactors make about 2370 TWh of electricity per year. The wholesale price of British electricity is about £40/MWh; making the world wholesale value of nuclear electricity about £95 billion/year. Compared to what MSRs could give we're throwing away £47 billion each year as heat which could've been made into extra electricity. All for the one time cost of £1 billion/£2 billion R&D we didn't spend to make MSRs real.

The US molten salt reactor experiment, MSRE, cost $5 million per year. Not the billions anti-nuclear power campaigners claim. Adjusted to today's money it works out at $30.52 pa., or £21.48 pa. Over 15 years that would cost Britain a total of $322 million.

Cost of R&D avoided: About half as much again as world electricity sells for, say: £47 billion (at wholesale prices)


Tuesday, 10 November 2015

How much krypton-85 leaks into the atmosphere each year?

A recent paper estimated krypton-85 activity in a cubic metre of air at 1.31 Bq. See: Variability of atmospheric krypton-85 activity concentrations observed close to the ITCZ in the southern hemisphere.

Measurements between August 2007 and May 2010 covered three wet seasons. The mean activity concentration of krypton-85 measured during this period was 1.31±0.02Bqm-3. A linear model fitted to the average monthly data, using month and monsoon as predictors, shows that krypton-85 activity concentration measured during the sampling period has declined by 0.01Bqm-3 per year.
The measurement, done over 3 years found krypton-85 levels were stable. neither increasing nor decreasing by much. I'll assume that krypton-85 released in balanced by decay.

How much krypton-85 could there be in the atmosphere?

The surface density of air = 1.217 kg/m3
Total mass of the earth's atmosphere = 5.1 × 1018 kg
Let's assume 1.217 kg/m3 of surface air has a krypton-85 activity of 1.31 Bqm-3
Let's next assume that krypton-85 activity is the same throughout the air. This will overestimate krypton-85 because its heavier than air. It's almost twice as heavy as carbon dioxide.
Proceeding with our over-estimation. Total activity of Kr-85 in all the atmosphere:
= (1.31 Bqm-3) × (5.1 × 1018 kg) / 1.217 kg/m3
= 5.49 × 1018 Bq

The Specific Activity of krypton-85:
= 400 (Ci/g) [Ci = Curie]
= 1.48 × 1013 Bq/g

So our over-estimation for the amount Kr-85 in earth's atmosphere:
= (5.49 × 1018 Bq) / (1.48 × 1013 Bq/g)
= 3.71 × 105 g
= 371 kg

How much krypton-85 is made each year

Krypton-85 is about 0.3% of fission products. Let's assume there is 400 GWe of nuclear reactor capacity on earth. That a 1GWe NPP operating over a year produces just less than 1 ton of fission products. Let's call that 400 tons fission products per year for all the world's reactors. That's works out at 1200 kg of krypton-85 made each year.

But all of krypton-85 does not leak into the atmosphere. Most of it is in sealed casks. The amount that leaks must be about the same as the amount that decays.

t½(Kr-85) = 10.7 years
λ(Kr-85) = 0.693 / 10.7 years = 0.064766355 years-1
How much Kr-85 is left after 1 year:
Fractional proportion at time t = N(t) / N(0) = e-λ t
= e-0.064766355 years¯¹ × 1 years
= e-0.064766355
= 0.93728643
How much Kr-85 leaks?:
= 371 kg × (1 - 0.93728643)
= 23.27 kg
Note: Estimating the amount of fission products made/year

This depends upon the total capacity of all the world's nuclear reactors. There are:

  • 435 commercial nuclear power reactors operable in 31 countries, with about 375 GWe of total capacity.
  • 180 nuclear reactors power some 140 ships and submarines.
  • 240 research reactors
I'll assume an average of 50Me per research and/or sea vessel reactor. So 420 × 50 = 21 GWe of small reactors. Let's round that to 400 GWe capacity for all reactors.

Sunday, 8 November 2015

How green anti-nukes closed a power plant delivering 620 megawatts of non-carbon electricity

Vermont Yankee was an electricity generating nuclear power plant, located in the town of Vernon, Vermont, USA. It generated 620 megawatts (MWe) of non-carbon electricity at full power. In 2008, the plant provided 71.8% of all electricity generated within Vermont, amounting to 35% of Vermont's electricity consumption.

  1. In May 2009, Vermont created the first statewide renewable energy feed-in law.
  2. Entergy requested a new state "certificate of public good" (CPG), but the Vermont legislature voted in February 2010 against renewed permission to operate.
  3. In 2011, the Vermont Electric Cooperative utility rejected a contract to buy Vermont Yankee power at below market rates:
    The board of directors at the Vermont Electric Cooperative, the third biggest power distribution company in the state, voted nine to one to reject a 20-year offer from Entergy to buy power from the 39-year old nuclear plant at below market prices.
    Their decision follows the lead previously set by Green Mountain Power and Central Vermont Public Service:
    "I really think today was a referendum on Entergy's relationship with the state of Vermont. In fact, we as a management team got a clear message not to speak with Entergy again"
    -- Dave Hallquist VEC CEO
  4. On 29 December 2014, Vermont Yankee owner Entergy ceased the plant's operations.
  5. Now the renewables advocates admit they can't provide renewable energy because the laws of physics just aren't right for the universe they live in.
    "Unless we get cost-effective storage, we can’t meet those goals — it’s a law of physics. The reason is because we’re trying to meet 100 percent of our annual energy needs with these projects that produce only 15 percent of the time. So you end up having to build six times the amount, and you end up having more generation than load, so there’s nothing you can do about it. We can’t meet our goals with the current physics."
    -- Dave Hallquist, CEO of VEC Vermont Electric Cooperative

Tuesday, 3 November 2015

The Hinkley Point deal is prohibitively expensive

So say the Guardian, again, today. It's not "prohibitively expensive" but it is "too expensive". Hinkley Point deal is too expensive is the common doxa, among both nukes, anti-nukes, and neutrals. The question of expense has interested me for sometime. Why so expensive, what can be done about that?

The AREVA EPR is the only modern reactor design currently approved by our regulator: Office of Nuclear Regulation (ONR). If we want a reactor right now, this is the only one we can build. Had we more choice, we could build nuclear power plants for much less than this. Probably about half the price. [KEPCO build their APR1400 reactors in UAE for £3¼ billion each] So why don't we? Given the EPR design is the only one with a current UK GDA, the obvious question to ask is: what's holding up the UK GDA process? The obvious answer is often: lack of resources. But what resources?

Government framed the UK nuclear reactor regulatory process to discourage vendors from applying for reactor approval and spent no effort encouraging vendors to apply to get reactors approved. In effect, that's how current regulation works in the UK. There was no design nor malice in this, just the habit government have of copying what seems to work elsewhere. UK government, basically, copied the US model (how US funds their NRC : Nuclear Regulatory Commission). NRC funding works reasonably well in the USA because it's a big country. US electricity demand is 11 times UK's. Because US population is 5 times ours, and per capita electricity use just over twice ours. After a US reactor GDA application is approved, the reactor vendor has reasonable confidence that many will be built. That allows Americans to justify the up front costs of gaining NRC approval. Not so in the UK. A vendor trying to build reactors here can't expect many of their reactors to be built here at all. The market for new builds is just not that large.

Electricity requirement of UK / US
Average demand (GW)Per capita use (kWh)Population
US46313,010320 million
UK425,95864 million

UK Government framed legislation such that a large fee, probably about £40 million, is charged up front for reactor approval. This is large enough to discourage vendors putting their designs forward for GDA validation. That, and the 5-year approval period. The UK GDA process began in 2007 with 4 competing designs: the AREVA EPR (PWR), the Toshiba-Westinghouse AP1000 (PWR), the GE-Hitachi ESBWR (BWR) and the AECL ACR1000 (Candu). The ESBWR and the Candu designs were withdrawn, leaving only 2. The AP1000 application was later suspended because the submission was not in S.I. units. That left only 1 reactor: EPR. Our system of taxing vendors beforehand led directly to GE-Hitachi pulling their ESBWR design out of the approval process despite spending £20 million on British approval. It partly led to AECL (Candu) not really trying. That might not be so bad in a world with lots of vendor competition. There are only about 7 such vendors in the world: AREVA (France), KEPCO (South Korea), Westinghouse (USA-Japan), GE-Hitachi (Japan), Rosatom (Russia), CANDU (Canada), Various Chinese. Some argue we should not consider Russian and Chinese designs due to security issues. CANDU reactors have positive voids, so many will not want them due to safety issues. That narrows the field down to 4 nuclear reactor vendors! So what other reactors could reasonably have been submitted for UK GDA? KEPCO have perfectly good designs they build at low cost (e.g. the APR1400 in UAE), but they've never been encouraged to apply for a GDA. That despite Britain and South Korea signing a special free trade deal in 2012. AREVA understood that their EPR design was too expensive at a very early stage: nearly 20 years ago. That's why they increased it's capacity from an initial 1100 MWe to 1650 MWe - to mitigate the expense by trying to gain an advantage in scale: in theory the cost of building and running 2 giant reactors being lower than 3 large reactors. It never panned out that way. Yet AREVA always had other designs it could've submitted for UK GDA. They had the KERENA and ATMEA1 designs too (since 2009 and 2007 respectively).

A better system would've seen the approval fee mostly paid for by a tiny tax on nuclear power, with an up front fee of, say 10% of approval costs. That would force immediate costs on the vendor of ~ £4 million. I think that would've encouraged KEPCO to apply for a GDA on a purely speculative basis. Imagine that it costs £40 million to approve a reactor for UK use. 10 different reactor approvals would cost £0.4 billion. A lot of money. The argument goes: the tax payer shouldn't have to cough up this money. Yet over a 35 year period, during which the Hinkley C contract for difference (CfD) applies, the electricity bill payer will cough up about £35 billion more than they would otherwise pay had their electricity been sourced at the current electricity wholesale price. We pay a tax anyhow. It's just that we're paying a tax at least 50 times larger than need be. Not quite: nearly all new nuclear power plants will need some kind of CfD but we could reasonably expect the difference in CfD and wholesale price to be half what it is for the EPR. So, instead of paying £35 billion more over 35 years, we'd pay £20 billion more over 35 years for a different reactor design.

  1. Guardian Live: should we say yes to nuclear power?
  2. KEPCO are building their APR1400 reactors in UAE for £3¼ billion each
  3. The costs of UK GDA for the AREVA EPR were said to be £35 million in 2012
  4. In 2007, GE-Hitachi Nuclear Energy Submitted ESBWR to UK Regulators for Generic Design Assessment (GDA)
  5. CfD: contract for difference. A CfD means that the customer pays more for electricity than they would were they paying the market price. It allows new electricity capacity suppliers to recoup their capital costs. Think of it like a mortgage. You buy the house now, live there but it takes you 25+ years to repay the cost.
  6. The saga of Hinkley Point C: Europe’s key nuclear decision
  7. vendor: I'm using the term vendor here to mean `nuclear power plant design and construction company`
  8. GDA = Generic Design Approval. This is like a licence and safety certificate allowing one to build several nuclear reactors in one country.