TK ° Comment #2, . ESTIEare OF THE An Cree CTS OF eorrey1 AND (GTRER ALPHA-ERITILUG TRANSUP AT ACS The estimate of lung cancer incidence associated with the inhalation . of plutonium (or otner transuranics) in particulate form is a critical factor, along with source tarms and resuspen ion, in defining the probable impact of the LhircR's plutonium based fuel-“cycle. oo . .is subject is discussed ‘in Sectien 4.6.5 "Particle Lung Dose Effects" eof WASH-1525. I quote the first sentence frem that section: So ; De "The estimates of lung cancer incidence associated witn the inhalation of transuranics used in this report are based upon a calculation of ine everece radiation cose delivered to the lurg and apalicezion ef tumor incidence estimates for tne uniformly irradiated Jung as estimated Boo s 7 , - | in the BEIR report."! This cited basis, and hence the derived estimates, are indefensible. Section 4.6.5 ree"that ‘insoluble’ particles of ‘ radioisotopes, when Cepusitea in tissues, provide focal spots of high radiation cose rates close the the particle," so there is no presuzstion . ‘that the exposure by particulates of plutonium is uniform. respiratory tissue of the lung is made up of 108 alveoli. is a complexiy organized unit of tissue. The deep Each aveolus If an insoluble alpha-emitting particulate is. depusited in this tissue some 10 to 160 alveoli will be exposed. A crude measure of the nonuniformity of this exposure is that at most about one-millionth of the lung's alveoli are affected by a single particulate. | The significance of the preceding is that in the actual lung exposure by an alpha-caitting particulate, the energy cf the ionizing radiation is denositca Jn a very limited voluine of tissue, and hence that sO, . the actual radiation dose “to lung tissue scaled roughly @ nillion times ~Ctotes ,