Information Notice 1985-81, Problems Resulting in Erroneously High Reading with Panasonic 800 Series Thermoluminescent Dosimeters

Problems Resulting in Erroneously High Reading with Panasonic 800 Series Thermoluminescent Dosimeters

ML031180279
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, 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, 05000262, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill
Issue date:	10/17/1985
From:	Jordan E NRC/IE
To:
References
IN-85-081, NUDOCS 8510150025
Download: ML031180279 (3)

SSINS No.: 6835 IN 85-81 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 October 173 1985 IE INFORMATION NOTICE NO. 85-81: PROBLEMS RESULTING IN ERRONEOUSLY HIGH

READING WITH PANASONIC 800 SERIES

THERMOLUMINESCENT DOSIMETERS

Addressees

All nuclear power reactor facilities holding an operating license (OL) or a

construction permit (CP) and certain materials and fuel cycle licensees who may

use the subject thermoluminescent dosimeters (TLDs).

Purpose

Information Notices IN 82-42 "Defects Observed in Panasonic Model 801 and 802 TLD's" and IN 85-42 "Loose Phosphor in Panasonic 800 Series Badge TLD Elements"

discussed two separate problems with Panasonic TLD's that resulted in erroneous

exposure measurements with the badges.

This information notice is provided to inform the licensees of two additional

problems that have resulted in erroneously high readings with Panasonic

800-series TLDs. It is expected that licensees will review this 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;

therefore, no specific action or written response is required.

Description of Circumstances

1. Self-Irradiation From Contaminated Lead Filters:

Several Panasonic TLD users have recently experienced anomalously high

readings. On investigation, it was determined that the lead filters in

the badges were contaminated with trace amounts of naturally occurring

radioisotopes. The lead filters (on both sides of the TLD elements) are

used to compensate for the energy dependence of calcium sulfate phosphor.

The lead used for these filters appears to be contaminated with radium-226 daughters. Bismuth-210 is a major dose contributor. Low level radiation

from these contaminants contributed up to 15 mrem in 30 days to the TLD

elements. During the initial investigation of the anomalous readings, several TLD badges were counted using a gamma spectroscopy system. This

technique was unable to identify contaminated lead filters because of the

low activity of gamma emitting contaminants. However, when lead filters

were recounted using a thin-window Geiger-Muller (GM) detector, they were

found to be contaminated with beta emitting radioisotopes.

8510150025

IN 85-81 October 17, 1985 Panasonic TLD's can be screened for contaminated filters by placing several

in a low background thin-window GM counter. Licensees wishing to use this

screening technique should select a counting time sufficient to provide an

acceptable lower limit of detection (5 pCi beta per gram of lead) for their

system. Panasonic is currently negotiating the replacement of badges on

a case-by-case basis.

2. Abnormal TLD Readings Caused by Hydrogen Sulfide (H2 S) Gas

On May 6, 1985, an unexpectedly high reading was indicated during a routine

TLD processing of a terminating contract worker leaving the Brunswick Steam

Electric Plant. The worker had been employed to clean marine life out of

the plants intake structure, an area where no radiation is expected. He

was issued a TLD because access to the job site was through the plant's

protected area. The worker's TLD (Panasonic Model UD-802) indicated 13,500

and 457 millirem on elements 1 and 2, respectively (both lithium borate TLD

material), with 1.2 and 1.4 millirem indicated on elements 3 and 4, respectively

(calcium sulfate TLD material). On investigation, the licensee has concluded

that the abnormal TLD response was caused by exposure to H2 S gas given off

by the decaying marine life in the intake structure. Extensive testing by

the licensee indicates that exposure to H2 S causes gross over-response from

lithiui borate TLD material. Multiple exposures to concentrations as low

as 10 parts per million (ppm) over a 12-hour period caused responses that

correspond to 250 millirem of radiation exposure. Indication as high as

7487L-ilTTi-ii-mwere obtained fro-mai4-hour-exposure to-114 ppm-H2 S. -

Several agents (such as chemical contaminants, ultraviolet light or extreme

humidity) are known to cause abnormal TLD responses. Licensees may wish to

provide appropriate means of protecting the TLD when exposure to these

agents is likely. However, licensees should ensure that protective coverings

or containers do not inhibit the TLDs ability to properly respond to actual

radiation exposure.

No specific action 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 regional office or this office.

ayrecto

Divisio f Emergency Preparedness

and Engineering Response

Office of Inspection and Enforcement

Technical Contacts: Roger Pedersen, IE

(301)492-9425 Jim Wigginton, IE

(301)492-4967 Attachments: List of Recently Issued IE Information Notices

Attachment 1 IN 85-81 October 17, 1985 .

LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

85-80 Timely Declaration Of An 10/15/85 All power reactor

Emergency Class Implementa- facilities holding

tion Of An Emergency Plan, an OL or.CP

And Emergency Notifications

85-17 Possible Sticking Of ASCO 10/1/85 All power reactor

Sup. 1 Solenoid Valves facilities holding

an OL or CP

85-79 Inade4uate Communications 9/30/85 All power reactor

Between Maintenance, facilities holding

Operations, And.Security -an OL or CP; research

Personnel and nonpower reactor

facilities; fuel

fabrication and

processing facilities

85-78 Event Notification 9/23/85 All power reactor

facilities holding

an OL or CP

85-77 Possible Loss Of Emergency 9/20/85 All power reactor

Notification System Due To facilities holding

Loss Of AC Power an OL or CP

85-76 Recent Water Hammer Events 9/19/85 All power reactor

facilities holding

an OL or CP

85-75 Improperly Installed Instru- 8/30/85 All power reactor

mentation, Inadequate Quality facilities holding

Control And Inadequate Post- an OL or CP

modification Testing

85-74 Station Battery Problems 8/29/85 All power reactor

facilities holding

an OL or CP

84-70 Reliance On Water Level 8/26/85 All power reactor

Sup. 1 Instrumentation With A facilities holding

Common Reference Leg an OL or CP

OL = Operating License

CP = Construction Permit