|Dear Sirs: I have red the draft and it seems to me that there is still room for significant improvements.|
a) First of all, the particularities of the final disposal systems seems not to be clearly explained neither clearly addressed. In Para 27 it is indicated that there are two safety cases, one for the operational phase (i.e. the accumulation of radioactive waste) and the other for the post-operational phase (i.e the start of the actual operation of the disposal system.) However, the document did not clearly indicate that the second safety case will be a preliminary one till the end of the operational phase. Being such the case the final version of such safety case will be ready just before closure, i.e. 50 or 100 years from the beguinning of the operation. At that time the current cirteria will not be necessarily valid, including this ICRP document, and the the state of the art will be well advanced compared with the present situation.
b) As there are two safety cases, the ICRP document should cleary address both situations, which is not the case because paragraph 30 indicates that there are two safety case but seem to refers only to the second safety case ("updates") . It shoud be stressed that while the operational safety case -the one that sould be approved by the Regulatory Authorities before start operation- should be revised periodically based mostly in the experience gained accumulating waste, the (preliminary) post-operational safety case should be revised periodically and the revision will be based on changes in the acceptability criteria as well as advances in the state of the art. It should be also indicated that the professional profiles of the persons addressing the periodical review in one case, and the update in the other case are completely different
c) In order to improve the understanding It is also strongly recommended to use the expression "disposal facility" for the operational phase and the expresion "disposal system" for the post-operational phase. The disposal facility will be transformed in a disposal system by the end of the operational phase when the original design is confirmed and the final engeennering barriers are constructed. Please note that the "construction" of a final disposal system end during the closure phase while the construction of the disposal facility is finalized just before starting the accumulation of waste.
d) Inter alia, Point 4.2, "Dose and risk concepts" should be written indicating that these concepts may be different by the time closure take place, and even unacceptable 100 yeras from now.
SOME DETAILED COMMENTS
a) The title should be modified indicating that this applies to HLW or indicating that it applies to high activity concentration of long lived solid radioactive waste. The text should be revised accordingly (see, for instance, lines 184 to 186).
Reason: At first it seem that applies even to material with, for instance, Pu in low activity concentration.
b) Avoid the use of the expression "permanent isolation", for some long lived radionucleides this seems to be physically impossible (see, para 3, line 308)
c) In line 432-433 (paragraph 13) should be modified the text to read ". . . and less concentrated level of long lived radionuclides."
d) Avoid the use of the word "never", such as in line 452. The slow release of long lived radionuclide (i.e. those where decay did not play a significant role) will gradually reduce their activiy concetration and some time in the future they will not be considered a hazard.
e) There are not "partial closure" (see line 1076). The fact that human access to some parts is prevented by enginnering barriers should not be mixed with the concept of closure.
With kind regards,
Former Head of the Radiological Safety Assessment Departemt, Division of Scientific and Technical Support, Nuclear Regulatory Authority of Argentina and former member of WASSC.