Hungary has approved a new legislation vowing to keep secret the key details of a nuclear power contract with Russia for 30 years.

According to the legislation, Hungary will not disclose the business and technical details of the agreement signed with Russian nuclear power corporation Rosatom for the Paks nuclear facility, reports Associated Press.

The agreement entails provision for construction of two new reactors at the nuclear facility, which is presently equipped with four VVER 440 reactor units, each having a capacity of 500MW.

The Soviet-built facility currently accounts for up to 50% of Hungary’s power requirements.

Secrecy is being maintained for national security reasons, according to the Hungarian Government.

The newly-formulated legislation is in line with similar protective guidelines maintained by other European countries.

Russia has provided €10bn as loan for the expansion project, which covers almost 80% of the construction costs.

Forty per cent of the set up at the facility is likely to be carried out by domestic firms.

Opposition parties in the country and civic groups have, however, termed the initiative to be unconstitutional as it conceals information contrary to public interest.