April 25th, 2011 -Unit 3 100% Leak rate – Updating Source Term – MELCOR analysis

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From: Gauntt, Randall 0 [[email protected]]
Sent: Monday, April 25, 2011 2:10 AM
To: PMT-japan Resource; Hoc, PMT12
Cc: Gepford, Heather; Meighan, Sean; Huffert, Anthony
Subject: RE: RESPONSE: Modification of Source Term; Email Distribution Request

Dear All,

I have been running MELCOR forensic analyses for the past month on the three reactor accidents in order to document and understand what happened.

This necessairly generates predictions of fission product release each time we run the analysis, which we have done dozens of times.

If this is what one calls a source term, then we are generating source terms several times a week for each reactor in addition to revised simulations of reactor and containment pressure response and estimated core damage fractions. But, I don’t think this is what you mean by modifying “The March 24th Source Term”.

We will be attempting to finally estimate a range of likely best estimate releases of fission products from the reactors as we gain better understanding of the sequence progressions and root out errors, bad data etc.

I have received a request from two people at the LLNL NARAC group for a guess at what we think is a most likely release profile from the reactors and they are interested from the standpoint of model validation and forensics examinations on measured downwind doses and land depositions given the weather conditions at the time of the accidents.

Concerning the “March 24 Assumptions” – we actually don’t make any assumptions about % core damage or containment release rate – this is actually what we are trying to simulate based on more fundamental assumptions such as operability and functioning of reactor systems such as isolation condenser and HPCI function in Unit 1, RCIC function and torus failure in Unit 2 and containment performance and water injections in all three reactors.

Let me know what else you might like to know.

From: PMT-japan Resource [[email protected]]
Sent: Sunday, April 24, 2011 10:35 PM
To: Hoc, PMT12
Cc: PMT-japan Resource; Gepford, Heather; Meighan, Sean; Huffert, Anthony; Gauntt, Randall 0
Subject: RESPONSE: Modification of Source Term; Email Distribution Request


Two items:

1. Please contact Dr. Randy Gauntt directly about the question in your email below. Randy’s email address is roqaunt(,sandia.,ov and phone number is 505-263-6849, and we’re ccing him on this email to facilitate your request. [Note to Randy: when responding to PMT12, include the PMT Japan Resource email address also]

2. For all emails that are sent to the “PMT Japan Resource” address, place Heather Gepford, Tony Huffert, and Sean Meighan on distribution also.

PMT Japan
Veather Gepford, Tony Huffert, Sean Meighan

From: Hoc, PMT12
Sent: Friday, April 22, 2011 11:54 AM
To: PMT-japan Resource
Subject: Modification of the Source Term

PMT Japan,

The question has been asked, are any efforts being taken to modify the source term?



The assumptions from the March 24th source term are as follows:

Unit 1: 70%, 10%/day leak rate
Unit 2: 33%, 5inch hold in containment
Unit 3: 33%, 100% leak rate



To your knowledge are any efforts being made? A simple “no” will suffice, but if the answer is “yes,” please define those efforts.

Thank you.
Kimberly Gambone

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