Information Notice 1985-54, Teletherapy Unit Malfunction

Teletherapy Unit Malfunction

ML031180217
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill, Barnwell
Issue date:	07/15/1985
From:	Partlow J NRC/OE
To:
References
IN-85-054, NUDOCS 8507110078
Download: ML031180217 (3)

SSINS No.: 6835 IN 85-54 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 July 15, 1985 IE INFORMATION NOTICE NO. 85-54: TELETHERAPY UNIT MALFUNCTION

Addressees

All NRC licensees authorized to use teletherapy units.

Purpose

This information notice is intended to alert users of teletherapy units of a

recent incident involving an Atomic Energy of Canada Limited (AECL) Theratron

60 unit. It is expected that licensees will review the information for

applicability to their facilities and consider actions, if appropriate, to

preclude a similar problem occurring at their facilities. However, suggestions

contained in this information notice do not constitute NRC requirements; there- fore, no specific action or written response is required.

Description of Circumstances

A pressure regulator switch (S15) on the pneumatic system to an AECL Theratron

60 teletherapy unit failed. As a result, the compressor in the unit continued

to run causing an overpressure condition in the holding tank. This condition

prevented the source drawer from immediately closing on command.

After treating a patient, the operator noticed that the compressor kept running

and that there was an unusual odor at the back of the machine. The machine was

then turned off. The operator notified management, but no maintenance was

ordered at the time. When more patients arrived, the machine was turned back

on and the treatments continued. After several patients had been treated, the

teletherapy unit failed to automatically return its cobalt-60 sealed source to

the shielded position. The operator observed that the indicator light on the

radiation monitor in the treatment room remained on after the unit timer reached

its zero setting. Attempts to turn off the unit by using the console controls

failed. The operator immediately removed the patient from the treatment room.

The pneumatically operated source drawer independently returned to the closed

position approximately an hour later.

Discussion:

An AECL representative has evaluated the incident and has concluded that this is

an isolated incident resulting from a failure to follow prescribed maintenance

8507110078

IN 85-54 July 15 , 1985 procedures on the unit. In this case, prompt emergency response by licensee

personnel to remove the patient from the treatment room after the failure

rather than continue efforts to return the source to the "off" position avoided

unnecessary radiation exposure.

No specific action or written response is required by this information notice.

If you have any questions regarding this matter, please contact the Regional

Administrator of the appropriate NRC regional office or this office.

Jame G. Partlow, Director

Division of Inspection Programs

Office of Inspection and Enforcement

H. Karagiannis, IE

(301) 492-9655 Attachment: List of Recently Issued IE Information Notices

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Attachment 1 IN 85-54 July 15, 1985 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

85-53 Performance Of NRC-Licensed 7/12/85 All power reactor

Individuals While On Duty facilities holding

an OL or CP

85-52 Errors In Dose Assessment 7/10/85 All power reactor

Computer Codes And Reporting facilities holding

Requirements Under 10 CFR an OL or CP

Part 21

85-51 . Inadvertent Loss Or Improper 7/10/85 All power reactor

Actuation Of Safety-Related . facilities holding

Equipment

• an OLor CP

85-50 Complete toss Of Main And 7/8/85 Allpower reactor

Auxiliary Feedwater At A PWR facilities holding

Designed By Babcock & Wilcox an.OL or CP

85-49 Relay Calibration Problem 7/1/85 All power reactor

facilities holding

an OL or CP

85-48 Respirator Users Notice: 6/19/85 All power reactor

Defective Self-Contained facilities holding

Breathing Apparatus Air an OL or CP, research, Cylinders and test reactor, fuel cycle and

Priority 1 material

licensees

85-47 Potential Effect Of Line- 6/18/85 All power reactor

Induced Vibration On Certain facilities holding

Target Rock Solenoid-Operated an OL or CP

Valves

85-46 Clarification Of Several 6/10/85 All power reactor

Aspects Of Removable Radio- facilities holding

active Surface Contamination an OL

Limits For Transport Packages

OL = Operating License

CP'= Construction Permit