ML19253A494
| ML19253A494 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 08/13/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Millen C PUBLIC SERVICE CO. OF COLORADO |
| References | |
| NUDOCS 7909100154 | |
| Download: ML19253A494 (1) | |
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UNITED STATES OM E *[ s. c W' h NUCLEAR REGULATORY COMMISSION gR
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,11 g 611 RYAN PLAZA DRIVE, SUITE 1000 AR LitJCToN, TEX AS 76012 August 13, 1979 Docket No. 50-267 Public Service Company of Colorado ATTN: M. C. K. Millen Senior Vice President P. O. Sox 840 Denver, Colorado 80201 Gentle =en:
The enclosed IE Bulletin 79-21 is forwarded to you for information. No written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely,
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'. Seyfrit/
Director
Enclosures:
- 1..IE Bulletin No. 79-21 2.
Listing of IE Bulletins Issued in Last 6 Months cc:
D. W. Warembourg, Nuclear Production Manager Fort St. Vrain Nuclear Station P. O. Box 368 Platteville, Colorado 80651 L. Brey, Manager, Quality Assurance O,
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UNITED STATES NUCLEAR REGULATORY C0m!ISSION OFFICE OF INSPECTION AND ENFORCEMF3T WASHINGTON, D.C.
20555 IE Bulletin No. 79-21 Date: August 13, 1979 Page 1 of 2 TEMPERATURE EFFECTS ON LEVEL MEASUREMENTS Description of Circumstances:
On June 22, 1979, Westinghouse Electric Corporation reported to NRC a potential substantial safety hazard under 10 CFR 21.
The report, Enclosure No. 1, addresses the effect of increased containment temperature on the reference leg water column and the resultant effect on the indicated steam generator water level. This effect would cauce the indicated steam genert or level to be higher than the actual level and could delay or prevent protection signals and could also provide erroneous information during post-accident monitoring. Enclosure No. I addresses only a Westinghouse steam gearrator reference leg water column; however, safety related liquid level measuring systems utilized on other steam generators and reactor coolant systems could be affected in a similar manner.
Actions To Be Taken By Licensees:
For all pressurized water power reactor facilities with an operating license:*
1.
Review the liquid level measuring systems within containment to determine if the signals are used to initiate safety actions or are used to provide post-accident monitering information. Provide a description of systems that are so employed; a description of the type of reference leg shall be included, i.e., open column or sealed reference leg.
2.
On those systems described in Item 1 above, evaluate the effect of post-accident ambient temperatures on the indicated vater level to determine any change in indicated level relative to actual water level. This evaluation must include other sources of error including the eff ects of varying fluid pressure and flashing of reference leg to steam on the water level measure-ments. The results of this evaluation should be presented in a tabular form similar to Tables 1 and 2 of Enclosure 1.
3.
Review all safety and control setpoints derived from level signals to verify that the setpoints will initiat a pv tha plant safety analyses throughout the range o instrumentation, including acci DUPLICATE DOCUMENT
$$({.1 these setpoints.
Previously entered
.in t sys e under
- Boiling water reactors have been the NRC to provide similar inform ANO ~790 M FO/ U No. of pages:
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