* Rebound from steep falls runs out of steam
* Radiation concerns keep investors on edge
* Small cap builders benefit from reconstruction expectations
TOKYO, March 24 (Reuters) - Japanese shares were little changed on Thursday, as their rebound from a steep fall last week ran out of steam on persistent worries about radiation leaks from a quake-stricken nuclear plant.
Although Tokyo stocks have recovered around 15 percent from an intraday low hit last week, worries that damage from a massive earthquake on March 11 and the subsequent accident at the nuclear facility could hurt corporate earnings kept investors on edge.
"The market has risen only because it was oversold last week, not because of any improvements in market factors. It's just in line with market theory," said Takashi Hiroki, chief strategist at Monex Securities.
"We are unlikely to see further gains in the near future, unless there's an end to the nuclear crisis in sight," Hiroki added.
The benchmark Nikkei average was up 0.1 percent at 9,464.96, while the broader Topix index fell 0.1 percent to 859.81 with its 200-day moving average at 871.36 seen as major resistance.
Small cap construction companies continued to benefit from expectations of reconstruction demand, while automakers such as Toyota suffered from worries about disruption in their supply chains.
(Reporting by Hideyuki Sano; Editing by Joseph Radford)