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Sidelined Issues in the Current Framework of the Nuclear Power

Plant Safety Rules for Volcanic Risk Evaluation

1

1

Makoto Murakami1

1 Institute of Seismology and Volcanology, Hokkaido University

Abstract

The nuclear disaster at Fukushima in 2011 gave rise to a large scale reformation of entire framework

of Japanese nuclear plant safety rules and regulations. Being part of this total restructuring of

nuclear plant safety rulings, a regulatory suite to take care of the volcanic risks on plants was newly

compiled and put into operation. This was the first time that such regulations dealing with volcanic

risk on nuclear plants were enacted in Japan. Although it is a certain progress that a fair treatment

for volcanic risks is authorized, the new regulatory suite still leaves some important issues sidelined.

Among those, this article pays particular attentions to necessities of fare treatment of floating pumice

raft posing threats on cooling water intake system and of introduction of probabilistic risk

assessment (PRA) methodology into volcanic risk evaluation.

Key Words: Nuclear Power Plant Risk Assessment, Volcanic hazard, Probabilistic Risk

Assessment (PRA), Pumice Raft

2011 3 M9

北海道地区自然災害科学資料センター報告Vol.32, 25-36, 2019

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66

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1)

2)

36

3)

4)

5) (2017a)

http://www.nsr.go.jp/data/000213308.pdf ( 2019/01/23)

6) (2015 2015 2 9

.https://criepi.denken.or.jp/jp/serc/denki/pdf/20150209.pdf 2019/01/23

7) (2017b

http://www.nsr.go.jp/data/000183879.pdf 2019/01/23

8) M. Jutzeler, R. Marsh, R.J. Carey, J.D. White, P.J. Talling, L. Karlstrom (2014): On the fate of pumice

rafts formed during the 2012 Havre submarine eruption, Nat. Commun., 5 (2014),

10.1038/ncomms4660

9) T. Simkin and R. S. Fiske (1983), Krakatau 1883 the volcanic eruption and its effects, Smithsonian

Institution press, p292.

10) 2009

11) (1927) 10 pp1-42

12) (1930) 2 pp105-112

13) 2015 : JEAG4625