ML100750421

Email from J. Bettle to R. Dennig, Subject: Crystal River Teleconference

ML100750421
Person / Time
Site:	Crystal River
Issue date:	10/08/2009
From:	Jerome Bettle Office of Nuclear Reactor Regulation
To:	Dennig R Office of Nuclear Reactor Regulation
References
FOIA/PA-2010-0010
Download: ML100750421 (3)

Text

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/ I Craver, Patti From: Bettle, Jerome Sent: Thursday, October 08, 2009 5:02 PM To: Dennig, Robert

Subject:

RE: Crystal River Teleconference Large RII complement on the call (lead office for the issue), someone from RES, 14-15 from NRR, CR3 Residents, and quite a few CR3 plant and corporate staff.

Plant staff indicated that they were about 11 days into a S/G replacement refueling outage that was scheduled to end sometime in December. They said the were assembling a number of containment, post tensioned concrete structure, and concrete nondestructive testing experts to assist them in determining the extent of the delamination. They think it might be 360 degrees around at the opening height (just above the equipment hatch) but would not guess as to any vertical dimension. They said they were aware of the 1976 dome delamination situation but had not really looked the resulting report and related documentation. They later said that they didn't think the cause(s) of the dome delamination were the same as for the current situation in the cylinder portion of the containment (despite not having determined the cause of the current situation nor looking at the documentation from the construction era problem). They are currently planning on changing the mounting for the S/G transfer device so as not to tax the indeterminate capability of the containment wall around the opening. They said they were also evaluating the impact on the containment polar crane rail support bracket that a delamination in that region of the containment structure might have. They said they detensioned 17 horizontal and 10 vertical tendons for the opening. (horizontal tendons are 120 deg from anchor to anchor overlapping with anchorages every 60 deg around the containment cylinder) The delamination on the drawings shows separation just outboard the horizontal tendon conduits, which are just outboard and essentially in contact with the vertical tendon conduits. The delaminated outer shell of concrete is about 9-12 inches thick and includes a rebar grid that the plant staff said was primarily there to prevent outer surface cracking.

I think I see an argument being made that the structural strength of the containment is from the tendon grid inward and the concrete and rebar outboard the tendons is there for missile shield and environmental protection duty.

My guess is that the tendons were put into tension squeezing the structure from there inward and the concrete and limited rebar grid outboard experienced the daily and seasonal temperature cycles and fatigued and fractured off as a delamination and that radial steel reinforcement probably could have held the concrete outboard of the tendons to the concrete inboard of the tendons. This might not be an issue for post tensioned containments without horizontal tendons. Non-post tensioned or metal containments need not apply.

The plant staff indicated that with their experts assistance they hope to determine the extent of the delamination by NDE and not by core boring (or hydro blasting) at various sample locations. They also said they were keeping all stakeholders informed of the extent of the condition as it became known and cause(s) as they were determined.

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From: Dennig, Robert Sent: Thursday, October 08, 2009 1:18 PM To: Bettle, Jerome

Subject:

FW: Crystal River Teleconference Please listen in From: Paige, Jason )n -

Sent: Thursday, October 08, 2009 1:15 PM To: Skeen, David; Dennig, Robert; Sullivan, Ted; Boyce, Tom (NRR); Ruland, William; Ashar, Hansraj; Brown, Eva; Mendiola, Anthony; Taylor, Robert; Khanna, Meena; Manoly, Kamal; Sheikh, Abdul; Thomas, George; Auluck, Rajender; Kuntz, Robert; Farzam, Farhad; Saba, Farideh; Glitter, Joseph; Howe, Allen; Nelson, Robert; Burnell, Scott; Bernardo, Robert; Hiland, Patrick

Subject:

FW: Crystal River Teleconference Below is the agenda that the Region 2 Branch Chief provided to me for the 3prm call with Crystal River.

Jason From: Sykes, Marvin 1 Sent: Thursday, October 08, 2009 11:43 AM To: Paige, Jason Cc: Ninh, Son; Hamman, Jeffrey; Franke, Mark; Munday, Joel

Subject:

FW: Teleconference

Jason, We are on-track for the 1500 telecon with the licensee. To participate, the NRC staff should call the HOO and ask to be connected to the bridge for the Crystal River containment issue.

2

I intend to provide some introductory remarks, allow each of the groups to introduce themselves and turn to discussion over to the licensee. We do not have a hard and fast schedule for completion of the call but I hope to have the-discussions wrapped within an hour.

This is the proposed meeting agenda.

(1) Introductions (2) Background information (generic discussion of discovery and actions to date)

a. Questions on the condition (3) Strategy

a. Mode 6

b. SG Change-out

c. Containment operability (root cause)

(4) Ongoing analyses

a. Vendor involvement

b. Timelines (5) Questions on actions (6) Recap and action items, including discussion on any required follow-up 3