Information Notice 1987-29, Recent Safety-Related Incidents at Large Irradiators

Recent Safety-Related Incidents at Large Irradiators

ML031190114
Person / Time
Issue date:	06/26/1987
From:	Cunningham R NRC/NMSS/IMNS
To:
References
IN-87-029, NUDOCS 8706220303
Download: ML031190114 (6)

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Attachment 2 IN 89-82 December 7, 1989 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS

WASHINGTON, D. C. 20555 June 26, 1987 NRC INFORMATION NOTICE NO. 87-29: RECENT SAFETY-RELATED INCIDENTS AT

LARGE IRRADIATORS

Addressees

All NRC licensees authorized to possess and use sealed sources in large

irradiators.

Purpose

i--

This notice is being issued to inform recipients of recent safety-related

incidents at large irradiators, which could have been prevented by proper

management aictions and attention to preventative maintenance programs. It:

is suggested that recipients review this information and their procedures

and consider actions, if appropriate, to ensure both proper preventative

maintenance programs and proper management actions at their facilities.-

However, suggestions contained In this Information Notice do not constitute

NRC requirements; therefore, no specific action or written response is required.

Description of Circumstances

A description of each of six events is provided in Attachment 1. In summary, these events included:

o hose failure resulting in a leak, failure to report the incident to NRC,

and deliberate cover-up of this incident when NRC tried to investigate, leading to company fines and personnel probation;

o intentional bypass of safety interlocks, resulting in'license suspension

and other enforcement actions by NRC;

o improper pipe routing and inadequate piping material, which broke and

caused partial loss of pool water;

o source unable to retract to its fully shielded position, due to a frozen

solenoid valve;

o a stuck source plaque, due to failure to promptly replace a frayed lift

cable; and

o a stuck source plaque, due to interference from the product carriers and

shroud.

8706220303

IN 87-29 June 26, 1987 Discussion:

These incidents illustrate a failure by management to assure that proper

safety and maintenance procedures are followed. It is suggested that super- visory personnel, particularly the Radiation Protection Officer and maintenance

personnel, be reminded of their responsibilities to assure safe operation at

their facilities. The incidents discussed in Attachment 1 demonstrate the

importance of:

1. prompt reporting of incidents to the NRC, as required by regulations or

license conditions

2. safety training and periodic retraining of personnel

3. not bypassing interlock systems or other safety systems

4. attention to proper plumbing installation and use of appropriate piping

material

5. proper maintenance of cables, carrier systems, and other components that

• could prevent radioactive sources from being retracted to a shielded

position.

No specific actions or written response is required by this Information

Notice. If you have any questions about this matter, please contact the

Regional Administrator of the appropriate NRC regional office or this office.

Richard E. Cunningham, Director

Division of Fuel Cycle, Medical, Academic, and Commercial Use Safety

Office of Nuclear Material Safety

and Safeguards

Bruce Carrico, K1SS

(301) 427-4280

Attachments:

1. Events That Occurred at Large Irradiator Facilities

2. List of Recently Issued NRC Information Notices

Attachment 2 IN 89-82 December 7, 1989 Attachment I

IN 87-29 June 26, 1987 EVENTS THAT OCCURRED AT LARGE IRRADIATOR FACILITIES

1. While the licensee was attempting to decontaminate pool water because of

a leaking source, a hose on a filtration system ruptured. Contaminated

pool water was then pumped onto the facility floor and leaked outside into

the surrounding soil. The licensee failed to report the incident to NRC,

and made deliberate efforts to prevent NRC's discovery of this incident.

"Subsequently, the licensee was indicted by a Federal Court. *Aconviction

resulted in a $35,000 fine for the company and two years probation for a

management employee. Licensee failure to make required reports prevents

the HRC from performing its radiological health and safety function and

from making a timely assessment of the nature and severity of an incident.

2. A licensee deliberately bypassed the safety interlock systems. The NRC

subsequently learned that licensee personnel had willfully violated

requirements, and that senior licensee management knew, or should have

known, of these violations. When NRC attempted to inspect and investigate

these suspected violations, senior licensee management knowingly provided

false information to the NRC. Subsequent enforcement action included

suspension of the license.

3. A water line fractured in the pool circulation system which resulted in

the loss of 5 feet of pool water. The line break led to a loss of

shielding water because the intake and outlet pipes were misaligned

during maintenance. The pipe break appears to have occurred because

the pipe was made of polyvinyl chloride, designed for cold water, rather

than for the heated water temperatures typical for the irradiator. The

piping was replaced with polypropylene pipe.

4. A night shift operator noticed that the travel time for the source to

reach the fully unshielded position was excessive. After completing

the next phase of irradiation, the source would not retract to the fully

shielded position, even using emergency equipment. The operator discovered

that the solenoid valve, that was supposed to retract the source to a

shielded position, was frozen due to weather conditions. The valve was

in a room above the irradiator facility. The operator went there and

turned on a room heater to thaw out the valve so that it would operate.

The operator violated license requirements to (1) notify the Radiation

Safety Officer (RSO) that the source had not returned to Its shielded

position because of the frozen valve, and (2)obtain RSO permission to

enter and heat the room housing the valve.

5. A licensee had identified a frayed lift cable a few days previously, but

instead of immediately replacing the cable, the licensee decided to wait

for scheduled maintenance. The cable Jammed and froze the source plaque

in a less than fully shielded position. Employees cut the cables and let

the source plaque free-fall into the pool. The incident could have been

prevented by replacing the frayed cable imuediately, and selecting cable

material with fray-resistant qualities.

Attachment 2 IN 89-82 December 7, 1989 6. A source plaque became stuck In the exposed position. Conveyors stopped,

'.A :ojirce DOWN 'ight came on, but cell radiation levels remained high.

Cable slack data indicated that the plaque was stuck about five and a half

feet down from its full-up position. The RSO attempted some raising and

lowering maneuvers, but the plaque then stuck in a full-up position. The

RSO, able to run the product containers out of the cell, saw some were

misaligned on the carrier. The RSO notified a State Inspector, who arrived

in the afternoon. It was determined that the plaque cable was off its pulley.

The bottom of a splice in the cable was resting on the lip of the tube

leading to the cell. After the cable was set on its pulley, the cable was

guided through the tube, and the plaque was lowered, until it caught again.

--A borrowed radiation-resistant camera arrived the next morning. An adequate

view of the plaque was obtained by midnight. Apparently the stationary

aluminum shroud between product containers and plaque had been deflected

and caught on the plaque frame. The plaque was carefully raised and dropped

to break the Jam. On the second try, the plaque broke free and dropped

into the pool. Analysis revealed that a product container had probably

tipped onto the shroud, causing interference with the plaque.

This incident was apparently caused by inadequate design of the shroud.

This led to the shroud deforming, which interfered with plaque motion.

Inadequate maintenance contributed to the problem. The cable should

have been replaced instead of spliced. A few months later, the entire

source hoist mechanism failed and had to be replaced. This failure oc-

• curred when the source plaque was submerged.

Attachment 2 IN 89-82 December 7, 1989 -2-

$ I

Attachment 3 IN 89-82 December 7, 1989 LIST OF RECENTLY ISSUED

NMSS INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

89-78 Failure of Packing Nuts on 11/22/89 All U.S. NRC licensees

One-Inch Uranium Hexafluoride authorized to possess

Cylinder Valves and use source material

and/or special nuclear

material for the heating, emptying, filling, or

shipping of uranium

hexafluoride in 30- and

48-inch diameter cylinders.

89-60 Maintenance of Teletherapy 08/18/89 All U.S. NRC Medical

Units Teletherapy Licensees.

89-47 Potential Problems with 05/18/89 All holders of operating

Worn or Distorted Hose licenses or construction

Clamps on Self-Contained permits for nuclear power

Breathing Apparatus reactors and fuel

facilities.

89-46 Confidentiality of 05/11/89 All holders of licenses

Exercise Scenarios for fuel cycle facilities

and byproduct material

licensees having an

approved emergency

response plan.

89-37 Proposed Amendments to 40 04/04/89 All U.S. NRC licensees.

CFR Part 61, Air Emission

Standards for Radionuclides

89-35 Loss and Theft of Unsecured 03/30/89 All U.S. NRC byproduct, Licensed Material source and special

nuclear material licensees.

89-34 Disposal of Americium 03/30/89 All holders of U.S. NRC

Wel1-Logging Sources specific licenses

authorizing well-logging

activities.

89-25 Unauthorized Transfer of 03/07/89 All NRC source, byproduct, Ownership or Control of and special nuclear

Licensed Activities material licensees.

t . a

4 Attachment 4 IN 89-82 December 7, 1989 Page 1 of I

LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

--- e --

DJAWOf

Inrormaliw

001_____. <_

Subject Issuance Issued to

Notice No.

89-59, Suppliers of Potentially 12/6/89 All holders of OLs

Supp. I Misrepresented Fasteners or CPs for nuclear

power reactors.

899C1 Inadequate Control af 12/6/89 All holders of OLs

Temporary Modifications or CPs for nuclear

to Safety-Related Systems power reactors.

89-80 Potential for Wdater Hanmre 12/1/89 All holders of OLs

Thermal Stratification, and or CPs for nuclear

Steam Sinding in High- power reactors.

Pressure Coolant Injection

Piping

89-79 Degraded Coatings and 12/1/89 All holders of OLs

Corrosion of Steel or CPs for LkRs.

Containment Vessels

89-56, Questionable Certification 11/22/89 All holders of OLs

Supp. 1 of Material Supplied to or CPs for nuclear

the Defense Department power reactors.

by Nuclear Suppliers

89-78 Failure of Packing Nuts 11/22/89 All NRClicensees

on One-Inch Uranium authorized to possess

Hexafluoride Cylinder and use source material

Valves and/or special nuclear

material for the heating, emptying, filling, or

shipping of uranium

hexafluoride In 30-

and 48-inch diameter

cylinders.

89-77 Debris in Containment 11/21/89 All holders of OLs

Emergency Sumps and or CPs for PURs.

Incorrect Screen

Configurations

89-76 Biofouling Agent: Zebra 11/21/89 All holders of OLs

1Nussel or CPs for nuclear

power reactors.

OL

• Operating License

CP

• Construction Permit

UNITED STATES PIRST CLASS MAIL

IPOSTAGE & FEES PAID

NUCLEAR REGULATORY COMMISSION USNAC

WASHINGTON, D.C. 20555 PERMIT No. 0 p

OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, 5300

-U Sup SvCs -' -. 4 1 A HVCS SVCS SECT

OC 20555