Principal Research Results

A Valuation Study ofFuel Supply Stability of Nuclear Energy
BackgroundIn the recent nuclear energy policy discussions ＊ 1, it was called for to visualize superiority of nuclear energy in terms ofsupply stability. Such external economy of nuclear power, however, has not been necessarily quantified and presented explicitly.

Objectives
In order to assess potential benefits of nuclear power with regard to its characteristics of fuel supply stability, the following
three aspects are valuated under the Japanese energy and electricity mix:a) economic stability; i.e. nuclear power's contribution to the whole energy and electricity mix in terms of resistance tofluctuation and/or fuel price hikes,b) procurement stability; i.e. natural uranium, the raw fuel material for nuclear power generation, is being imported from
more reliable sources through adequately diverse markets than in the cases of oil and natural gas, and,c) passive reserve effect; i.e. fuel materials as running stocks at power stations and fuel service facilities could maintain
nuclear power generation running for a certain duration under unexpected disruption of fuel supply.

Principal Results
In this study, fuel supply stability is assumed as robustness against instabilities and uncertainties surrounding Japan's energy
resource acquisition and supply of energy services. In this respect, the following three features were picked up and analyzed quantitatively. The major findings are summarized as follows:
1. Economic Stability.
A simulation of Japan's optimal power generation mix up to the year 2030 showed that, in the case of fossil fuel pricedoubling over the base case settings, the average generation cost in 2030 will rise by 2.3 JPY/kWh than the baseline result when thenew addition of 13 units of nuclear power reactor is realized as currently planned, and by 3.5 JPY/kWh if the new addition is limited
to the 3 units currently under construction or preparation, respectively. When the price hike of fossil fuel is as much as 5 times, themagnitude of generation cost increase goes up to 9.4 and 13.8 JPY/kWh, respectively. These figures are explained as mitigation of30% in the additional expenditure by an average household consuming 300 kWh per month with addition of 10 units of nuclear power(Fig.1).
2. Procurement Stability.
We induced an index of procurement stability through quantifying those factors such as; global distribution of resources,
global market structure, distribution of Japan's imports as well as socio-political stability of those countries with resource deposits andexport. Under the current circumstances, quantification of risk rank of each fuel showed that procurement risk of uranium fuel is as
low as one third of oil, while coal is as good as uranium fuel. Applying the results to evaluation of Japan's primary energy mix, thestudy revealed that the primary energy structure has evolved with remarkable improvements in its robustness since the period of theoil crises in 1970s (Fig.2).
3. Passive Reserve Effect.
The nuclear fuel cycle system contains significant amount of fuel materials as normal running stock at power reactors andfuel cycle facilities. In Japan, as of the end of 2006, those stored materials corresponded to 2.35 times Japan's annual fuel needs,
which can be further enhanced by recycling recovered materials from spent nuclear fuel reprocessing. In the longer run, moreadvanced recycling can improve the self-sufficiency of nuclear fuel dramatically.

Future Developments
Each of the analyses should be reviewed whenever notable changes and developments take place in any of those fuelsegments and markets. As an extension of the study, we strive to develop meaningful indices of energy security.
Main Researcher: Koji Nagano, Dr. Eng.
Senior Researcher, Energy Technology Policy Sector, Socio-economic Research Center
Reference
K. Nagano et al, 2008 “A Valuation Study of Fuel Supply Stability of Nuclear Energy”, CRIEPI Report Y07008 (in Japanese)＊1：See “Japan's Nuclear Energy National Plan” Nuclear Energy Subcommittee (2005)

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5. Nuclear

Fig.1 The impacts of fuel price hikes to Japan’s generation mix: additional burden per average
household in 2030.

5Fig.2 The historical evolution of Japan’s primary energy mix and its procurement stability index.
RISK INDEX: The procurement stability index reflects instability of energy mix induced from global resource distribution, global tradeshare, Japan’s import structure of each energy resource as well as socio-political risks of countries with resource deposits or exports. TheRISK INDEX has its maximum value 1 when all the primary energy needs are met solely by imported oil, while its minimum value 0
when the energy supply is preoccupied by domestic risk-free sources, such as hydro and other renewables.

(a) The short-term reserve effect.

(b) The long-term effect by recycling.

Fig.3 The passive reserve effect of Japan’s nuclear power system: comparison of stored energy.
[Note] R/Q : stored energy divided by energy amount consumed annually.
The total energy quantity stored in each reserve is shown on the bottom of (a). d: day, y: year.
The width of bar reflects annual energy consumption of each energy source, meaning the area of each bar equals to the total energy
quantity stored.

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