Shielding fuel assemblies used to protect the belt-line weld of the reactor pressure vessel from fast neutron radiation in Ringhals unit 3 and 4 - 128

The belt-line weld on the reactor pressure vessel of Ringhals units 3 and 4 has a lifetime estimate of 40 years under the current operating conditions. In the event of power up rates and lifetime extension the irradiation embrittlement of the belt-line weld may be a limiting condition. One way to solve this problem is to limit the fast neutron radiation on the reactor pressure vessel. This paper will focus on a solution with specially designed assemblies for the positions that have the highest influence on the fast neutron dose for the belt-line weld. (authors)