Catalyzes the hydrolysis of nucleoside triphosphates, with a preference for pyrimidine deoxynucleoside triphosphates (dUTP, dTTP and dCTP). a ribonucleoside 5'-triphosphate + H2O = a ribonucleoside 5'-phosphate + diphosphate + H(+) a 2'-deoxyribonucleoside 5'-triphosphate + H2O = a 2'-deoxyribonucleoside 5'-phosphate + diphosphate + H(+) dUTP + H2O = diphosphate + dUMP + H(+) dUTP + H2O = diphosphate + dUMP + H(+) dTTP + H2O = diphosphate + dTMP + H(+) dCTP + H2O = dCMP + diphosphate + H(+) dCTP + H2O = dCMP + diphosphate + H(+) Monomer. Belongs to the Nudix hydrolase family. NudI subfamily.