ML20056B706
| ML20056B706 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 03/05/1970 |
| From: | Mcelroy D NORTHERN STATES POWER CO. |
| To: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 9102080392 | |
| Download: ML20056B706 (1) | |
Text
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1 MSP NORTHERN STATES POWER COMPANY
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g7 MAR 91970*- ;2 Dr. Peter A. Morris, Director Division of Reactor Licensing a,t nag United States Atomic Energy Commission 8Murma Washington, D.C.
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Dear Dr. Morris:
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MONTICELLO NUCLEAR GENERATING PLANT E-5979 Docket No. 50-263 Regulator" File Cy.
The ACRS, as set forth in its report letter of Janua$y 10, 1970, has determined that a limited program of vibration monitoring is appropriate for the Monticello j
reactor during preoperational tests and initial operation. We met with members of your staff on February 25 and described the vibration monitoring program that will be undertaken in response to the ACRS request. Subsequently we were in-formed that the proposed program is acceptable to the DRL staff.
The vibration monitoring program for the Monticello reactor will utilize eight displacement sensors located in two areas of the reactor internals as,1) shroud flange, and 2) jet pump assembly. The primary intent is to measure, both hot and cold, the most important vibration characteristics.
The specific locations of the sensor instruments are as follows:
- 1) Four (4) displacement sensors located at 90* positions near the shroud flange and measuring relative motion between the shroud and the pressure i
vessel tmder hot and cold conditions.
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- 2) Two (2) displacement sensors located at two individual jet pump risers and indicating tangential motion of the risers with response to the pres-sure vessel, measured under hot and cold conditions.
- 3) Two (2) displacement sensors on a single jet pump assembly, located on each of the two jet pump throat areas and measuring the relative radial motion between the jet pump throats and pressure vessel, under hot and cold conditions.
Installation work is proceeding for the equipment required under this program so that vibration monitoring data collection can begin during the preoperational test period.
Yours very v,
MID/
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