ML19296B401
| ML19296B401 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 02/13/1980 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0312, RTR-NUREG-312 NUDOCS 8002200508 | |
| Download: ML19296B401 (2) | |
Text
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400 Chestnut Street Tower II February 13, 1980 Director of Nuclear Reactor Regulation Attention:
Mr. Thomas A. Ippolito, Chief Branch No. 3 Division of Operating Reactors U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Ippolito:
In the Matter of the
)
Docket No. 50-296 Tennessee Valley Authority
)
This letter provides information regarding modifications to the feedwater nozzle and feedwater sparger inspection performed on the Browns Ferry Nuclear Plant unit 3 during the fall 1979 refueling outage.
This information is provided in accordance with NUREG-0312.
In accordance with plans submitted by letter from J. E. Gilleland to you dated May 7, 1979, the feedwater sparger final-fix modification (as described in General Electric Company's Topical Report NEDE-21821), nozzle clad removal, and ultrascnic inspections were performed on the Browns Ferry unit 3 reactor vessel. As part of the c.1 adding removal and new sparger installation, a surface examination was performed on all machined surfaces. No relevant indications were found.
Before performing the in-vessel work all fuel was removed, the in-ves.sel work platform was installed, and lead shielding was installed at the vessel wall in the platform area. The working field was 400-500 mrem /hr at the in-vessel platform. The total number of pecole involved was approximately 110, and the total exposure was approximately 150 man-rem.
In response to the recommended action by GE in SIL No. 208 to provide increased margin against feedwater nozzle crack initiation and propagation, we provide the following status on the measures taken by TVA as of the unit 3 outage.
O u 8002200 0N
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5!r. Thomas A. Ippo.ito February 13, 1980 1.
The reactor water cleanup piping was rerouted during the unit 3 outage to equally distribute the return ficw to all feedwater lines.
2.
Operation procedures have been revised where possible to reduce the temperature differentials between the feedwater and reactor water during all modes of operation.
3.
The addition of a low-flow feedwater control valve in parallel with tha turbine-driven feedwater pumps is now in the design stage. This system redesign will largely eliminate temperature transients induced by on/off operation of feedwater flow at low pcwer levels.
Very truly your,
TENNESSEE VALLEY AUTHORITY
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j, W M. Mills, Manager Nuclear Regulation and Safety