Information Notice 1986-30, Design Limitations of Gaseous Effluent Monitoring Systems

Design Limitations of Gaseous Effluent Monitoring Systems

ML031220651
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
Issue date:	04/29/1986
From:	Jordan E NRC/IE
To:
References
IN-86-030, NUDOCS 8604280122
Download: ML031220651 (4)

SSINS No.: 6835 IN 86-30 UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF INSPECTION

AND ENFORCEMENT

WASHINGTON, D.C. 20555 April 29, 1986 IE INFORMATION

NOTICE NO. 86-30: DESIGN LIMITATIONS

OF GASEOUS EFFLUENT MONITORING

SYSTEMS

Addressees

All nuclear power reactor facilities

holding an operating

license or a con-struction

permit.

Purpose

This notice is provided to alert licensees

to two design limitations

noted in the use of Eberline's

SPING-4 (system particulate

iodine and noble gas) gaseous effluent monitoring

systems. The first deals with the limitations

of the detection

capability

of the SPING-4 monitoring

system. Some licensees

are incorrectly

relying on the SPING-4 to meet all of the post-accident

require-ments of NUREG-0737.

The second deals with noble gas adsorption

that could interfere

with routine operational

low-level

monitoring.

It is expected that recipients

will review this information

for applicability

to their facilities

and consider actions, if appropriate, to preclude problems related to these limitations

at their facilities.

However, suggestions

con-tained in this notice do not constitute

NRC requirements;

therefore, no specif-ic action or written response is required.Description

of Circumstances:

The Eberline SPING-4 is designed to monitor radioactive

noble gasses, particu-lates and iodines in plant gaseous effluents.

By using three overlapping

channels, the noble gas (NG) monitor has a detection

capability

of 10-7 to 105 pCi/cc (Xe-133 equivalent).

The low-range

channel employs a beta scintillation

detector.

The mid- and high-range

channels of the NG monitor use energy-compensated

GM tube detectors.

Conformance

to NUREG-0737 II.F.1: Item II.F.1.1 of NUREG-0737, "Clarification

of TMI Action Plan Requirements," issued November 1980, requires licensees

to have the capability

to detect and measure concentrations

of NG fission products in plant effluents (up to lo5 pCi/cc for undiluted

containment

exhaust) during and following

an accident.Recent NRC regional inspections

of NUREG-0737 implementation

indicate that 8604280122 IN 86-30 April 29, 1986 some licensees

have installed

SPING-4 monitors and mistakenly

consider them adequate to meet all of the requirements

of Item II.F.1.1.

Although the SPING-4 does have an upper detection

capability

of 105 pCi/cc, its associated

microcomputer

is vulnerable

to radiation

damage from a total integrated

dose greater than 1000 rads. Therefore, it is unlikely the SPING-4 would survive the course of an accident.

Eberline has indicated

that the SPING-4 was designed primarily

as a normal-range

monitor with extended capabilities

for brief excursions

to concentrations

greater than 102 pCi/cc. Full-range

moni-toring consistent

with Item II.F.1.1 can be achieved by using the SPING-4 in conjunction

with an accident monitor (with a remote microprocessor)

such as Eberline's

model AXM-1. The accident monitor comes on line when excessively

high activity levels are sensed while the SPING-4 isolates itself and goes into a purge cycle.Noble Gas Adsorption:

Eberline has noted noble gas adsorption

with the plastic scintillator

while performing

a SPING-4 calibration.

This calibration

compared the SPING-4 output with a GeLi detection

system output, as the concentration

of a reference

gas (Xe-127) was decreased.

The concentration

of Xe-127 (initially

at 210 pCi/cc)in the closed test loop was decreased

by vent and dilution operations.

Cali-bration was interrupted

after 2 days to correct problems with the GeLi system.The system was allowed to stand idle for 10 days with 0.3 pCi/cc Xe-127 concen-tration. When the calibration

resumed, the response of the beta scintillator

did not decrease in the expected proportions.

An investigation

indicated

that both the inner and outer mylar sheets that cover the plastic scintillator

had adsorbed Xe-127 gas.Although the levels of activity used in this calibration

were much higher than those normally encountered, the noble gas adsorption

noted on the low range of the detection

system could indicate a generic operational

concern. The high background

resulting

from the adsorbed gas could cause overestimations

in any effluent release calculations

that are based on the monitor output. This is particularly

true if low-level

monitoring

is resumed following

either a large activity excursion

(3 or 4 orders of magnitude

above normal) or an extended moderate increase (1 order of magnitude

for a week or more). Following

such releases the monitor should be purged and a new background

taken. It should be noted that this gas adsorption

phenomenon

is probably not unique to SPING-4 monitoring

systems. Other manufacturers

of plastic scintillation

detectors

use similar construction

techniques.

Any effluent monitor that employs a plastic scintillation

detector may experience

the same difficulties.

IN 86-30 April 29, 1986 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.ward L. Jordan Director i Division of Emergency

Preparednes

and Engineering

Response Office of Inspection

and Enforcement

Technical

Contact: Roger L. Pedersen, IE (301)492-9425 James E. Wigginton, IE (301)492-4967 Attachment:

List of Recently Issued IE Information

Notices

Attachment

1 IN 86-30 April 29, 1986 LIST OF RECENTLY ISSUED IE INFORMATION

NOTICES Information

Date of Notice No. Subject Issue Issued to 86-29 86-28 86-27 Effects of Changing Valve Motor-Operator

Switch Settings Unauthorized

Transfer and Loss of Control of Indus-trial Nuclear Gauges Access Control at Nuclear Facilities

Potential

Problems In Generators

Manufactured

By Electrical

Products Incorporated

Traceability

And Material Control Of Material And Equipment, Particularly

Fasteners 4/25/86 4/28/86 4/21/86 4/17/86 4/11/86 86-26 86-25 All power reactor facilities

holding an OL or a CP All licensees

author-ized to possess and use industrial

nuclear gauges.All power reactor facilities

holding an OL or CP, research and nonpower reactor facilities, and fuel fabrication

& pro-cessing facilities

All power reactor facilities

holding an OL or CP All power reactor facilities

holding an OL or CP All power reactor facilities

holding an OL or CP; research and test reactor facilities;

fuel cycle licensees

and Priority 1 material licensees All power reactor facilities

holding an OL or CP All power reactor facilities

holding an OL or CP and research and test reactors 86-24 Respirator

Users Notice: 4/11/86 Increased

Inspection

Frequency For Certain Self-Contained

Breathing

Apparatus

Air Cylinders 86-23 Excessive

Skin Exposures

Due To Contamination

With Hot Particles Underresponse

Of Radition Survey Instrument

To High Radiation

Fields 4/9/86 3/31/86 86-22 OL = Operating

License PIr r,.^-,4>.

n,.