ML20086D703

Telecopy Ro:On 770223,while Withdrawing in-sequence Control Rod to Bring Reactor Critical,Reactor Period of Less than 5 Obtained

ML20086D703
Person / Time
Site:	Monticello, 05000000
Issue date:	02/24/1977
From:	Eliason L NORTHERN STATES POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19289B550	List: 05000000/LER-1977-012, :on 770620,during Investigation of Cycle 5 Max Critical Power Ratio Limits,Ge Found That Pump Trip Delay Time Assumed in Original Cycle 5 Transient Analysis Not Appropriate.Amend Request Will Be Submitted 05000000/LER-1977-020-03, /03L:on 770404,RCS Leakage Determined to Be Greater than 10 Gpm.Caused by Packing Leakage Past Stems on RTD Bypass Throttle Valves 13RC20 & 14RC20.Valves Placed on Backseat & Stem Leakage Decreased 05000000/LER-1977-038-03, /03L:on 770519,RCS Leakage Determined to Be Greater than 10 Gpm from Stem Leakoff on Manual Isolation Valves 1PS24 & 1PS28 for Pressurizer Spray Valves.Caused by Packing Leakage.Valves Will Be Repacked at Next Outage ML20086D481 ML20086D514 ML20086D520 ML20086D537 ML20086D550 ML20086D554 ML20086D557 ML20086D561 ML20086D567 ML20086D606 ML20086D642 ML20086D691 ML20086D703 ML20086D760 ML20086D788 ML20086D818 ML20086D823
References
NUDOCS 8312020461
Download: ML20086D703 (1)

Text

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BiKSRB NORYHERN STATES POWER COMPANY F0hTICEll/> h'lCLEAR GDT: RAT 1h'G PlJdG FOhTIG11/), FrIhWESOTA 55362 gg

• PILE 0000, February 24, 1977 Mr. J. G. Keppler, Director Region III~

Office of Inspection and Enforcement  ;

United States hbclear Regulatory Corrassion l 799 Roosevelt Road I Glen Ellyn, Illinois 60137 l

Dear Mr ~Keppler:

I FONTICELID NIELEAR GDFutATING PIN!f Docket No. 50-263 License No. DPR 22 On Febniary .25,1977, sdille withdrawing an in-sequence control rod to bring i the reactor critical, a reactor period of less than 5 seconds was obtained, '

Analyses perfonned by the NSP core analysis group shows that the corbination of high temperature and hip,h renen concentration at the time of the occurrence, established conditions such that criticality occurred on an unusually high reactivity worth control rod notch. The obsenred period was consistent with the core analysis data.

Yours very truly,

,-s .

L.'R. E11 on Plant Fhnager LRE/kik cc: Director, Office of Mwiagement Infonnstion 6 Program Control G. Charnoff '

Minnesota Pollution Control Agency l Attn: J. W. Ferman  !

File Copy sent to telecopier to Mr. Keppjer.

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