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Bano, MahmoodaFrom: Scott, MichaelSent: Saturday, March 26, 2011 2:15 AMTo: LIA02 Ho cCc: LIA03 Hoc; Casto, Chuck; Monninger, John; Dorman, Da nSubject: RE : ACTION - Decommissioning,/Type Information for Ops Center

I think this is more what they were looking for, rather than the licensing discussionpreviously sent. Please advise me when this is fully vetted and can be released to theJapanese. Thanks.

From: LIA02 HocSent: Friday, March 25, 2011 12:25 PMTo: Scott, MichaelCc: LIA03 HocSubject: FW: ACTION - Decommissioning Type Information fo r Ops CenterSome more information.Steve----. riginal Message -----From: Richards, StuartSent: Wednesday, March 23 , 2011 6:51 PMTo: Camper, Larry; Bowman, Gregory; Rini, BrettSubject: FW: ACTION - Decommissioning Type Information fo r Ops Center

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From: Rahimi, MerajSent: Wednesday, March 23, 2011 5:50 PMTo: Ordaz, Vonna; Benner, Eric; ET05 Hoc; RST01 Hoc; Richards, StuartCc: White, Bernard; Mohseni, Aby; Davis, Jack; Weaver, Doug; Doolittle, Elizabeth; Waters,Michael; Kinneman, John; Bailey, Marissa; Tschiltz, MichaelSubject: RE : ACTION - Decommissioning Type Information fo r Ops CenterHere is the proposed SFST/FCCS/HLW coordinated response:We would not recommend early entombment considerations due to the high thermal loads andassociated negative effects on entombment material properties. In fact, we believe it mightnot be prudent to entomb at all. We believe that Japan should consider waiting until thecore or spent fuel debris can be cooled sufficiently and then removed similar to TMI. Wewould initially recommend pumping continuously borated water into the molten core or spentfuel pool. Longer term, if entombment is considered by Japan, it is our opinion thatentombment would be less problematic (with respect to criticality issues) if the entombmentis around the molten core or pool, rather than directly onto the fuel and in the primarycontainment vessel. We believe that heat transfer will be a significant challenge and thusit would be best if the entombment was built with low and high vents that would enable thetransfer of heat through air convection. If the entombment is considered by pouring sometype of material on the molten core or spent fuel pool the system reactivity and heattransfer capability is highly dependent on the material of use. We believe, the temperaturein the reactor core or the dried spent fuel pool is too high fo r the concrete to cure. Bothconcrete (especially wet) and sand would be a neutron moderator and could raise criticality

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,doncerns. Whatever is used should be carefully evaluated. Due to the unknown configurationin the core, any medium should conservatively be heavily borated. Another option maybe theuse of sand with boron frits which would turn into glass when contacted with the molten core.This would immobilize the radionuclides. However, the temperature at which the sand is added*must be at the point that the glass can solidified. This may require longer cooling time.In the interim while options are considered, it might be advisable to confine the core or thepool with filtered flexible enclosure.

Meraj RahimiChief of.Criticality, Shielding, an d Dose Assessment Branch Division of Spent Fuel Storageand Transportation Office of Nuclear Materials Safety and Safeguard U.S. Nuclear RegulatoryCommission6003 Executive Blvd., Suite 301Rockville, MD 20852Phone: 301-492-3338Fax: 301-492-3348e-mail: meraj.rahimi@nrc.gov

From: Ordaz, VonnaSent: Wednesday, March 23, 2011 3:21 PMTo: Benner, EricCc: White, Bernard; Mohseni, Aby; Davis, Jack; Weaver, Doug; Rahimi, Meraj; Doolittle,Elizabeth; Waters, Michael; Kinneman, John; Bailey, Marissa; Tschiltz, MichaelSubject: ACTION - Decommissioning Type Information for Ops CenterImportance: HighEric,SFST has the lead to coordinate a response with HLW an d FCSS, an d respond to the ReactorSafety Team, the ET Response Coordinator, and Stu Richards in the Operations Center with a CCto Dan Dorman by 6pm.Thanks,VonnaFrom: Ordaz, VonnaSent: Wednesday, March 23, 2011 3:13 PM-To: Richards, Stuart; Weaver, Doug; Mohseni, Aby; Davis, JackCc: RSTO1 Hoc; Bowman, Gregory; Hickman, John; Lee, Richard; Rini, Brett; Case, Michael;McConnell, Keith; Watson, Bruce; Camper, Larry; Deegan, George; Waters, MichaelSubject: RE: Decommissioning Type InformationThanks, Stu. We'll get back to you.VonnaFrom: Richards, StuartSent: Wednesday, March 23, 2011 2:32 PMTo: Weaver, Doug; Mohseni, Aby; Davis, JackCc: RST01 Hoc; Bowman, Gregory; Hickman, John; Lee, Richard; Rini, Brett; Case, Michael;McConnell, Keith; Watson, Bruce; Camper, Larry; Deegan, George; Ordaz, Vonna; Waters, MichaelSubject: RE: Decommissioning Type InformationImportance: High

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.Dan Dorman has asked the Ops Center to respond to a number of questions related to theJapanese event.Can NMSS respond to the following?8. What should they be considering with respect to criticality prevention and decay heatremoval during the entombment period?The goal is to provide the response to the Ops Center by 6 pm tonight.I will forward you the original request, which may help.ThanksStuFrom: Deegan, GeorgeSent: Wednesday, March 23, 2011 2:05 PMTo: Richards, Stuart; Camper, LarryCc: RST01 Hoc; Bowman, Gregory; Hickman, John; Lee, Richard; Rini) Brett; Case, Michael;McConnell, Keith; Watson, BruceSubject: RE: Decommissioning Type InformationStu- As your email came in, Brett Rini and I were speaking with one another. I indicatedthat FSME will be working on #7 (licensing requirements) and #9 (whatever relevant info wecan pull together from the TMI event), but that the best shop fo r criticality type issues(Question #8) is probably NMSS.From: Richards, StuartSent: Wednesday, March 23, 2011 1:51 PMTo: Camper, LarryCc: Deegan, George; RST01 Hoc; Bowman, Gregory; Hickman, John; Lee, Richard; Rini, Brett;Case, MichaelSubject: RE : Decommissioning Type InformationLarryRES might be able to help you with Question #8. Richard Lee in DSA is our POC on this one.We'can provide you some thoughts on enclosures, but I agree that a good answer will take alo t of time and a lo t more information on the status of the units.StuFrom: Camper, LarrySent: Wednesday, March 23, 2011 12:49 PMTo: Dorman, DanCc: Deegan, George; RSTO1 Hoc; Bowman, Gregory; Hickman, JohnSubject: Decommissioning Type InformationDan,Greetings! Trust you are holding up well over there! Regarding your message of earlier today,we will be able to provide feedback on Question number 6 today by the 18:00 timeframe.Questions 6,8 and 9 will require a bit of review and interface with RES but we will startthat process today. Standby fo r a better timeline on those. The staff did some work on theentombment issue via a couple of SECY's but the approach died out because it became clearthat industry was not going to utilize it in the US. Of course, the situation in Japan isquite different etc. Regardless, our earlier work should be of some benefit but we just have

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.to resurrect it and review etc. In thinking ahead just a bit, I suspect that we will need toput together some sort of Task Force or think tank type group to analyze possible pathsforward for the overall decommissioning of the site an d for the related waste management etc.Of course, we have some time to think about this issue but not too long etc.

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