  A reference material designed for the determination of natural radionuclides
in solid samples (glass pellets) is described and the results of certification
are presented. The material has been certified for 7 natural radionuclides
(40K, 226Ra, 228Ra, 228Th, 232Th, 235U and 238U). An information value is given
for 210Pb. Radon (222Rn) emanation experiments showed results comparable within
participating laboratories, however, the number of data and precision was too
low to carry out a certification process. The reference material may be used
for quality management of analytical laboratories engaged in the high-sensitive
analysis of radionuclides in the construction materials of detectors placed in
ultra low background underground laboratories.
