ML20084D756

Ro:On 701119,control Rod Drive J-6 Failed to Move from Position 00 W/Control Rod Drive Pressure.Caused by Teflon Split Ring Spacer Inadvertently Left in Drive.Drive Will Be Monitored Periodically

ML20084D756
Person / Time
Site:	Dresden
Issue date:	12/18/1970
From:	Hoyt H COMMONWEALTH EDISON CO.
To:	Morris P US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084D760	List: ML20084D756 ML20084D767
References
04979, 4979, NUDOCS 8304120319
Download: ML20084D756 (2)

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L - Com monwealth Edison ComI>anv .

ONE F1RST NATOONAL PLAZA

• CHICAGO. ILLINOIS POST OPPICE 80X 747

• C H I C A G O, ILLINO45 40490 Dresden Nuclear Power Sta tica R. it. :j l Morris, Illino is 60450 Decembe: 18, 1970 Dr. Det :c . Por r ia , :)irectot h iv i ; ion o f '

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Dear Dr. ':

orris:

Th ic le t t e r i:: to reper* a con litior. relating to t he opera t ie:: of the station ia anich centrol red i:-ive L .13 (J -6) ' *a s leclared ino;1erable as reynired by section 3.3./.. ci t L e T 2chnical S;'ecif ica tions.

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co::.c- - ' ioa .- .ettiim ir t o tc t. notches in the f. irs t hal' of tts :troke was somewhat slower than normal. This is indicative of increased friction in tr.e drive r.echanism. The drive was stroked several additional times arm was sermi tes ted twice. The scrna tir.es for 907. inse * , ion were 3.00 and .'.96 sco.' - ,. ra - h i c- c:; t,a-- o ,

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1: ..od i ie 'o re.ao' c t E t; arive fro: the r'i 't cr ior inipet . ion at 'ho ext er y , li ,

io _ :h.n 10, l'DO , b:!ve J-6 was removed fro. the renctor. It was disas-m -

v :.< in ;pe ;t eJ c: ecc. r 16, l') 70.

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Dr. I ite r A. ?!orria, Director  ! m c o n.b- r 11:, 1970

) The cause of the erratic operation and apparent increased T-fotion ua; found l

/tobeateflonsplit ring spacer was used in drive reassembly procedure which

/ inadvertently left in the drive during the previous drive ou rhaul. This type

/ of spacer is 'ao longer used in Unit 2 control rod drives.

The reassembly of overhauled drives will be r.iore closely monitored La the tuture to prevent this type of occurrance.

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