The costs of nuclear used fuel management

Two procedures for the end of cycle

After three to four years in the nuclear reactor core, used fuel must be managed in what is called the &uot;end of cycle&uot;.

If the aim is to do more than simply put the used fuel in long-term storage and leave the problem for future generations to deal with, one of two approaches may be taken.

The choice recycling

The first approach - perfectly operational - consists of processing the used fuel in order to collect its residual uranium (around 95%) and plutonium (1%). These materials can then be recycled in the form of:

• New fuels using enriched uranium
• MOX fuel (&uot;Mixture of OXides&uot;) 

The end waste (about 4% of the initial nuclear material), is encased in glass in very low volume for permanent disposal. Its radioactivity is reduced by the extraction of plutonium.

It is also subject to recycling and packing for storage:

• Structural elements of used fuel
• Technological waste

The choice of direct storage

The second approach consists of encapsulating the used fuel for permanent storage without separating out the constituent parts (&uot;direct storage&uot;). This approach is not taken anywhere in the world today. Indeed, there are no countries still fully going down this route.

Very different impacts on the environment

Direct storage leads to:

• Burying all the radiotoxicity contained in the used fuel
• The abandonment of the energy potential in the uranium and plutonium

An economic comparison of the two approaches cannot therefore be made. We need to take into account the &uot;plutonium factor&uot;.

Other approaches to consider

If burying plutonium is prohibited, which is the case in France today, then it must undergo intensive processing, at a much higher cost.

If the plutonium can be buried, there are two options. The first is clearly the direct disposal of the used fuel, which is regarded as waste. In this case, it still contains all its radiotoxicity.

The second would be to simplify the processing procedure. This translates into:

• The presence of a bit more plutonium in the end waste (but much less than in the used fuel)
• Significantly lower costs (amounting to about 30% in a plant designed on the basis of simplified processing)

A comparison of provisional costs

In 1994, the OECD (Organization for Economic Cooperation and Development) conducted a study on the costs of the fuel cycle. In particular it carried out an economic comparison of the two back-end cycle methods. The available provisional costs were compared without taking into account externalities (indirect costs or savings).

The assessment of the updated average costs of the fuel cycle feeding a reactor to be commissioned in 2000, for its entire life (30 years), found little economic difference between recycling and direct disposal.

Given that this is long term management incorporating significant investments, a very low actuarial rate should be selected to avoid the result depending purely on the choice of payment schedule relevant to each solution. Therefore, for a zero actuarial rate, the costs of both methods are virtually the same: 1.2 Franc centimes (0.18 Euro centimes) per kwh.

In any case the difference between the two assessments is low due to the uncertainties in the calculations. In the case of recycling, the cost of direct disposal of the ultimate waste must be added to the recycling itself: 0.11 Franc centimes (0.17 Euro centimes) per kwh according to the study.

No real experience in direct disposal

The cost of recycling is based on already quite considerable industrial experience (almost 15,000 tons of used fuel already reprocessed, almost 1,000 tons of MOX fuel produced). That of direct disposal on the other hand is based on &uot;paper studies&uot; centered around concepts not yet given international consensus. The cost forecasts for this method are therefore marred by major hazards, very probably by underestimation.

A more recent study by the DIGEC

The 1997 study by the Department of Natural Gas, Electricity and Coal (DIGEC) is based on the same methodology as the OECD study (reactor to be commissioned after 2000).

It opts for a provisional recycling cost of 1.0 to 1.2 Franc centimes (0.15 to 0.18 Euro centimes) per kwh attributed to the time of production of the kwh (or even 1.5 to 1.7 Franc centimes (0.23 to 0.26 Euro centimes) per kwh attributed to the time of recycling). The updated direct disposal cost selected is 0.3 Franc centimes (0.046 Euro centimes) per kwh.

The table below shows the various back-end cycle costs according to the breakdown created by EDF for 1995. The amounts will decrease with the amortization of the installations and the accumulation of industrial experience.