ML031110177

E-mail from J. Strosnider to A. Thadani, Regarding Decision on Davis Besse RPV Head

ML031110177
Person / Time
Site:	Davis Besse
Issue date:	10/22/2002
From:	Strosnider J Office of Nuclear Regulatory Research
To:	Mayfield M, Thadani A Office of Nuclear Regulatory Research
References
FOIA/PA-2003-0018
Download: ML031110177 (1)

Text

LRobert Tregoning - DECISION ON DAVIS-BESSE RPV HEAD.^ Page 1 From: Jack Strosnider,, 4t.--

To: Ashok Thadani; Michael Mayfield Date: 10/22/02 1:28PM

Subject:

DECISION ON DAVIS-BESSE RPV HEAD Ashok, Mike; I had a call this afternoon from Brian S., John Z., Tad M., and Bill D. regarding the subject we discuss this morning about whether or not we need additional material from the Davis Besse RPV head. The licensee is pushing for a decision from NRC, as they want to get the head off site. I explained that if we want to provide a full probabilistic evaluation (with uncertainties, etc.) of the probability of failure of an RPV head with degradation like Davis Besse that additional information would be necessary on cladding properties and the flaw distribution in the cladding. Per our discussion this morning, I noted that this would probably cost several hundred K and that the data would take a significant amount of time to generate. The NRR folks indicated that they didn't really think this was necessary to support the SDP. They also indicated that they wanted to know if there was any value in removing nozzles #24 and #46. There has been some discussion about the possibility that these nozzles could provide information on the potential for penetration cracking without visible leakage indication. It was noted that a plan on exactly what would be done with the nozzles and how the information would be used would be needed to support their removal.

Finally, Bill Dean said that there has been some recent discussion about removing additional material from different heats of nozzles, I assume for crack growth studies. Bottom line of the conversation was that NRR would like to know Wednesday morning if we think getting any additional material from the Davis Besse head is justified. If not, they want to send the licensee a letter releasing the hold on the head. We need to discuss Wednesday morning.

thx, Jack CC: Brian Sheron; Nilesh Chokshi; Richard Barrett; William Dean