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QFFICE OF AIR AND RADIA.TION David C. Moody, Manager Carlsbad Field Office Department of Energy P.O. Box 3090 Carlsbad, NM 88221 Dear Dr. Moody: On Oetober 30, 2006, the Environmental Protection Agency (EPA) received the Department of Energy's (DOE) "Transuranic (TRU) Waste Acceptance Criteria (WAC) for the Waste Isolation Pilot Plant, Revision 6.0, DOE/WIPP-02-3122" for review.
EPA's review of Revision 6.0 of the WAC determined that this document eontains few changes that are specific to the radioactive eoniponent of the waste. It does however, remove the requirement for performing visual examination (VE) on a statistically determined sample of the waste eontainers to verify the results of radiography, also referred to as "VE as a QC check of radiography." (See 2 °a paragraph under Section G.1, Appendix G of the WAC, Rev. 6). Based on EPA's current waste characterization inspection experience, EPA concurs that, for TRU wastes that have well defined acceptable knowledge (AK), VE as a verification check for radiography may be unnecessary as a routine test. IHowever, EPA is concerned that in the future, as a result of the Iimitations of AK or due to the complex nature of a waste stream, the estimation of cellulosics, plastic, and rubber (CPR) contents of the waste containers by radiography alone may be difficult and could result in an erroneous quantification of the waste material parameters (WMPs) and assignment of the waste summary category group (SCG). This may result in over or underestimation of CPR quantities which in tun2 may affeet future WIPP performance assessment results. Therefore, EPA expects the Carlsbad Field OFfice to ensure that waste generator sites retain the capability to perform"VE as a QC check on radiography" as an option for retrievably-stored, contact-handled (CI1) T RU waste. Therefore, during EPA inspections, EPA may require generator sites to perform VE on a select number of retrievably-stored CH TRU containers that have undergone radiography to verifylcompare CPR values obtained via radiography. Such a comparison would ensure that the CPR quantifred by radiography are of suffrcient aecuracy and provide a defensible input value necessary for the future WIPP performance assessments.

1,ntemetA4eress(uRF) o hrPJrw°,rrv.ep2.gov Recyctezti,Recyclabie & Prir,ed with Ye,etzbie Oii Based inks on ? 00% Posicensumer. ?rocess Ohiorine Frea RecYcietl Paoer2 EPA previously deternlined that the WAC contains signi tic

~~ ?t3y less detail on the characterization techniques used for remote-handlerl (Rii i-. aste than on th.e techniques used for CH waste (A-98-49, II-B3-99). Because ihese d' °ercet ,ernain ia Revision 6 of the WAC, EPA continues to expect eacli RI1 sisc __ & .oa t s€ characterization plans based on the Waste Characterization Pro14S €1 z ZInPl: n

~ ;:io ' ~.~~ 1 (WCPIP).
Thank you for providing us with an opportunity to 1

- =svie,v the Revision 6.0 of the WAC. If you have any questions or concerns, please contact Rajani Joglekar (202-343- 9462) or Ed Feitcorn (202-343-9422).


### Sincerely,

Juan 1?eves, Dirrcto. Raoa.F0:1P°ott 'tio;. D;Visio3:

cc: (Electronic Distribution) Lloyd I'iper, CBFO Vernon Daub, CBFO Courtland Fesmire_ CBFO Ava Holland, CBFO Norma Castaneda, CBFO Martin Navarrete, CBFO Dennis Miehls, CBFO Allison, Pangle, CTAC Wayne Ledford, CTAC