The numbers quoted, and duly credited, were from an article in International Business News, a usually reliable source. In the research I did for this article, and it was quite extensive, no mention was made that the incidence of thyroid cancer in children was under question. It seems likely that in the shadow of Chernobyl, Fukushima would produce similar results. The incidence of thyroid cancer post Fukushima does not appear to be a settled matter. Here is a quote from The Lancet (December 2016).
"The possibility of a causal association between radiation exposure and thyroid cancer in Fukushima, Japan after the 2011 nuclear disaster is a controversial topic. In The Lancet Diabetes & Endocrinology, Noboru Takamura and colleagues1 prematurely and misleadingly dismiss the radiation effect in attributing cases of thyroid cancer detected in Fukushima as 'an effect of screening caused by the use of modern, highly sensitive ultrasound technology.' ”