  A new method of searching for neutron clusters (multineutrons) composed of
neutrons bound by nuclear forces has been introduced and implemented. The
method is based on the search for daughter nuclei that emerge at the nuclei
cluster decay of 252Cf to neutron clusters. The effect of long-time build-up of
daughter nuclei with a high atomic number and long half-life was utilized. As a
result, the cluster decay of Cf-252 to a daughter nucleus U-232 (half- life of
T1/2= 68.9 years) was discovered. It is assumed that the emergence of U-232
nuclei is attributed to emission of neutron clusters consisting of eight
neutrons - octaneutrons. The emission probability of octaneutrons against
{\alpha}-decay probability of Cf-252 is defined equal to
{\lambda}C/{\lambda}{\alpha} = 1.74*10-6.
