ML19260D239
| ML19260D239 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 01/31/1980 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Pilant J NEBRASKA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 8002080170 | |
| Download: ML19260D239 (1) | |
Text
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CENTRAL FILES PDR:HQ UNITED STATES LPDR f'ed arow%,
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- January 31, 1980 Docket No.
50-298 Nebraska Public Power District ATTN:
J. M. P11 ant, Director Licensing & Quality Assurance Post Office Box 499 Columbus, Nebraska 68601 Gentlemen:
This IE Information Notice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the informa-tion for possible applicability to their facilities.
No specific action or response is requested at this time.
If further NRC evaluations so indicate, an IE Circular or Bulletin will be issued to recommend or request specific licensee actions.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely,,
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'Karl V. Seyfrit Director
Enclosures:
1.
IE Information Notice No. 80-03 2.
List of IE Information Notices Recently Issued cc:
L. C. Lessor, Superintendent Cooper Nuclear Station Post Office Box 98 Brownville, Nebraska 68321 sooaoso (3 0
UNITED STATES SSINS No.:
6870 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT 7912190666 WASHINGTON, D.C.
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a IE Information Notice No. 80-03 Date: January 31, 1980 Page 1 of 2 MAIN TURBINE ELECTR0 HYDRAULIC CONTROL SYSTEM Description of Circumstances:
On September 6, 1979, while performing a routine startup of the Trojan Nuclear Plant, a speed control problem was encountered during warmup of the General Electric turbine and increase of turbine speed to normal operating speed (1800 RPM). Technicians were notified and trouble shooting in accordance with the technical manual was commenced to resolve the apparent oscillation between the primary and backup speed control circuits which was hindering normal turbine startup operations.
The technical manual indicates that it is permissible to remove either the primary or backup low value gate circuits which contain speed and acceleration error amplifiers.
Upon removal of the primary low value gate circuit card, the backup card amplifiers, coming from a saturated condition, became the controlling circuit. During the shift in control circuits (primary to backup), the speed / acceleration error signal went to maximum which resulted in a full open signal to the turbine control valves. Under existing plant conditions this appeared to the safety injection system as a major steam break downstream of the main steam isolation valves which resulted in a safety injection system actuation and reactor trip.
The Electrohydraulic Control System (EHC) technical manual indicated that slight load changes are likely when a low value gate card is removed.
The effect on an unloaded turbine appears to be much more significant and tests conducted by Trojan personnel indicate that the transient is initiated whether the turbine is at a set speed or in an acceleration mode to a set speed.
Discussions with General Electric personnel by the licensee have been initiated in an attempt to verify the phenomenon observed and, if applicable, alert other facilities which operate a turbine with a MK 1 EHC System regarding the potential operation of the control valves when trouble shooting the speed control unit in accordance with existing instructions.
- GEK Instruction Book 11381-D, " Speed Control Unit," Maintenance Section, Page 4.
IE Information Notice No. 80-03 Date: Janua ry 31, 1980 Page 2 of 2 This information is provided as an early notification of a possible significant matter.
It is expected that recipients will review the information for possible applicability to their facilities. No specific action or response is requested at this time.
If further NRC evaluations so indicate, an IE Circular or Bulletin will be issued to recommend or request specific licensee actions.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
IE Information Notice No. 80-03 Janua ry 31, 1980 LISTING OF RECENTLY ISSUED IE INFORMATION NOTICES Inf o rmation Subject Date Issued To Notice No.
Issued 79-33 Improper Closure of 12/21/79 All power reactor Primary Coctainment facilities holding Access Hatches Operating Licenses (OL) and Construction Permits (cps) 79-34 Inadequate Design of 12/27/79 All holders of of Safety-Related Heat power reactor Exchangers Operating Licenses (OLs) and Con-struction Permits (cps) 79-35 Control of Maintenance 12/31/79 All power reactor facilities and Essential Equipment with an Operating Licenses (OLs) and Construction Permits (cps) 79-36 Computer Code Defect 12/31/79 All holders ci power reactor Stress Analysis of Piping Operating Licenses (OLs)
Elbow and Construction Permits (cps) 79-37 Cracking in Low Pressure 12/28/79 All holders of power reactor Turbine Discs Operating Licenses (OLs) and Construction Permits (cps) 80-01 Fuel Handling Events 1/4/80 All holders of power reactor Operating Licenses (OLs) and Construction Permits (cps) 80-02 8X8R Water Rod Lower 1/25/80 All BWR Facilities End Plug Wear holder of power reactor Operating Licenses (0Ls) or Construction Permits (cps)
Enclosure
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