Some of Europe's 143 nuclear reactors are likely to fail a test simulating terrorist attacks, an EU Commissioner said, and others will likely see insurance bills soar as politicians try to tighten regulations.

Following the nuclear crisis in Japan, caused by an earthquake and tsunami last month, the European Union is planning to carry out tests by the year end to assess whether its reactors could survive severe conditions.

The tests would simulate terrorist attacks either via cyberspace or an airplane crash and would focus on the reliability of reactor cooling systems, says a Reuters report.

Following the catastrophe in Japan, the German government hastily postponed its decision to extend the life spans of the country's 17 reactors and took the seven oldest off-line pending a three-month safety check, the report says.

Berlin previously agreed in September to keep the nuclear plants -- operated by RWE, E.ON, EnBW and Vattenfall -- running 12 years longer on average than their original shutdown date.