Editing IPCC:AR6/SR15/Chapter-4 (section)

==== 4.3.1.3 Nuclear energy ====

<div id="section-4-3-1-3-block-1"></div>

Many scenarios in Chapter 2 and in AR5 (Bruckner et al., 2014) <sup>[[#fn:r123|123]]</sup> project an increase in the use of nuclear power, while others project a decrease. The increase can be realized through existing mature nuclear technologies or new options (generation III/IV reactors, breeder reactors, new uranium and thorium fuel cycles, small reactors or nuclear cogeneration).

Even though scalability and speed of scaling of nuclear plants have historically been high in many nations, such rates are currently not achieved anymore. In the 1960s and 1970s, France implemented a programme to rapidly get 80% of its power from nuclear in about 25 years (IAEA, 2018) <sup>[[#fn:r124|124]]</sup> , but the current time lag between the decision date and the commissioning of plants is observed to be 10-19 years (Lovins et al., 2018) <sup>[[#fn:r125|125]]</sup> . The current deployment pace of nuclear energy is constrained by social acceptability in many countries due to concerns over risks of accidents and radioactive waste management (Bruckner et al., 2014) <sup>[[#fn:r126|126]]</sup> . Though comparative risk assessment shows health risks are low per unit of electricity production (Hirschberg et al., 2016) <sup>[[#fn:r127|127]]</sup> , and land requirement is lower than that of other power sources (Cheng and Hammond, 2017) <sup>[[#fn:r128|128]]</sup> , the political processes triggered by societal concerns depend on the country-specific means of managing the political debates around technological choices and their environmental impacts (Gregory et al., 1993) <sup>[[#fn:r129|129]]</sup> . Such differences in perception explain why the 2011 Fukushima incident resulted in a confirmation or acceleration of phasing out nuclear energy in five countries (Roh, 2017) <sup>[[#fn:r130|130]]</sup> while 30 other countries have continued using nuclear energy, amongst which 13 are building new nuclear capacity, including China, India and the United Kingdom (IAEA, 2017; Yuan et al., 2017) <sup>[[#fn:r131|131]]</sup> .

Costs of nuclear power have increased over time in some developed nations, principally due to market conditions where increased investment risks of high-capital expenditure technologies have become significant. ‘Learning by doing’ processes often failed to compensate for this trend because they were slowed down by the absence of standardization and series effects (Grubler, 2010) <sup>[[#fn:r132|132]]</sup> . What the costs of nuclear power are and have been is debated in the literature (Lovering et al., 2016; Koomey et al., 2017) <sup>[[#fn:r133|133]]</sup> . Countries with liberalized markets that continue to develop nuclear employ de-risking instruments through long-term contracts with guaranteed sale prices (Finon and Roques, 2013) <sup>[[#fn:r134|134]]</sup> . For instance, the United Kingdom works with public guarantees covering part of the upfront investment costs of newly planned nuclear capacity. This dynamic differs in countries such as China and South Korea, where monopolistic conditions in the electric system allow for reducing investment risks, deploying series effects and enhancing the engineering capacities of users due to stable relations between the security authorities and builders (Schneider et al., 2017) <sup>[[#fn:r135|135]]</sup> .

The safety of nuclear plants depends upon the public authorities of each country. However, because accidents affect worldwide public acceptance of this industry, questions have been raised about the risk of economic and political pressures weakening the safety of the plants (Finon, 2013; Budnitz, 2016) <sup>[[#fn:r136|136]]</sup> . This raises the issue of international governance of civil nuclear risks and reinforced international cooperation involving governments, companies and engineering (Walker and Lönnroth, 1983; Thomas, 1988; Finon, 2013) <sup>[[#fn:r137|137]]</sup> , based on the experience of the International Atomic Energy Agency.

<div id="section-4-3-1-4"></div>

<span id="energy-storage"></span>