NUREG/CR-1156

Environmental Assessment of

Ionization Chamber Smoke Detectors

Containing Am-241

Prepared by R. Belanger, D. W. Buckley and J. B. Swensen

Science Applications, Inc.

Prepared for

U. S. Nuclear Regulatory

Commission
NOTICE

This report was prepared as an account of work sponsored by

an agency of the United States Government. Neither the

United States Government nor any agency thereof, or any of

their employees, makes any warranty, expressed or implied, or

assumes any legal liability or responsibility for any third party's

use, or the results of such use, of any information, apparatus

product or process disclosed in this report, or represents that

its use by such third party would not infringe privately owned

rights.

Available from

GPO 'Sales Program

Division of Technical Information and -Document Control

U.S. Nuclear Regulatory Commission Washington, D.C. 20555

and

National Technical Information Service

Springfield, Virginia 22161
NUREGriCR-1156

SA1 01379-729LJ

Environmental Assessment of

Ionization Chamber Smoke Detectors

Containing Am-241

Manuscript Completed: October 1979

Date Published: November 1979

Prepared by

R. Belanger, D. W. Buckley and J. B. Swenson

Science Applications, Inc.

(1200 Prospect Street

La Jolla, CA 92038

Prepared for

Division of Fuel Cycle and Material Safety

Office of Nuclear Material Safety and Safeguards

.U.S. Nuclear Regulatory Commission 4'

Washington, D.C. 20555

NRC-02-78-045

EXECUTIVE SUMMARY

Residential fires continue to pose a major problem in the United

States, ranking as the second most frequent cause of accidental death in the

home. Between 7,500 and 12,000 lives are lost in fires every year with 70

percent of these occurring in residential fires. Residential property loss due

to fires is over one billion dollars annually. A key element in reducing loss of

life and property is early detection of fires. Various devices are available

that detect flames, heat, or products of combustion. In recent years devices

that detect products of combustion ha-ve been introduced to the consumer market

and their sales have increased dramatically. These so-called "smoke" detectors

are of two types. The majority have been of the ionization chamber smoke

detector (ICSD) type which contains small amounts of radioactive material. The

remainder have been of the photoelectric type which contains no radioactive

material. A combination detector has been recently marketed that contains both

an ICSD and a photoelectric detector. Based on theoretical studies and case

histories, the estimated percent of residential fire-related deaths that smoke

detectors could save is between 41 and 89 percent.

Most ionization chamber smoke detectors contain americium-241 (Am-241),

a radioactive substance that emits ionizing radiation. Other radionuclides could

be used in place of Am-241.. In the past, radium-226 (Ra-226) has been used in

detectors, but at present it is not'employed in the consumer product. Nickel-63

(Ni-63) is presently being studied for use in consumer smoke detectors, having

already been used in commercial applications such as in large warehouses. The

user of an Am-241 ICSO is exempt from regulations, but the manufacturer must

apply for and obtain a specific license from the Nuclear Regulatory Commission to

distribute the product. The license is granted only after the applicant has

demonstrated that the product is designed and will be manufactured in a manner

such that specific requirements and safety criteria are met.

Since 1972-1973, the residential market for Am-241 ICSDOs has increased

rapidly. Fourteen million units containing a total of 41 curies of Am-241 were

distributed in 1978 and 26 million units have been distributed since 1972. Based
upon present projections, about 90 million units will be distributed by 1986.

The peak year of distribution should be 1978. The average activity per unit in

1978 was 3 uCi and projections indicate this will become lower in the future.

The distribution of photoelectric detectors has been minimal compared

to ICSD's. Early photoelectric units were not as reliable as comparable ICSO's

because of various reasons, in particular, the use of incandescent bulbs. The

introduction of low-power light emitting diodes has improved their reliabil.ity

considerably. The cost of photoelectric units is greater than the cost of

comparable Am-241 ICSD's, basically because of slightly more complex circuitry.

The photoelectric units have been found to react quicker to smoldering or

slow-burning fires while the ICSD's react quicker to fast-burning fires. Both

appear to have responses comparable in terms of saving lives. However, it is.

felt the ICSD units may have a slight edge over the photoelectric units since

response is more critical to fast-burning fires.

The nonradiological impacts due to use of both ICSD's and photoelectric

detectors have been determined to be slight and indistinguishable from one

another. For a typical residential installation, the risk of an occupant being

exposed to nonradtological toxic products, due to burning for example, is judged

to be extremely smai 1.

The use of Am-241 ICSD's does result in exposure of people to low

levels of radiation. Analysis shows that the manufacture, distribution, normal

use, and disposal of 14 million Am-241 ICSD's each containing 3 uCi of Am-241

will result in a collective total body dose of 110C.oerson-rem. The useful life

is assumed to be ten years. Disposal is by either sanitary landfill or

incineration. Fourteen million ICSD's will service about 21 million people.

Analysis also shows the risk to the exposed population is about 0.1 fatal cancer..

The normally-occurring cancer mortality rate for the total population of the

United States is about 370,000 per year or about 35,000 per year for a group of

21 million people.

A comparison of these numbers illustrates the relatively small risk

involved in using an Am-241 ICSD. It should be noted the 370,000 cancer deaths

per year are actual deaths while the 0.1 fatal cancer over ten years of ICSD use

was calculated using conservative assumptions. The ratio of the potential lives

saved to the possible fatal cancers due to use of ICSO's ranges from 15,000 to

51,000.
Analysis of potential accidents with Am-241 ICSD's showed the dose

commitments received by maximally exposed individuals to be significantly within

the safety criteria standards required by the Nuclear Regulatory Commission.

Comparative analyses based upon cost, risk, and benefits, found present

day Am-241 ICSD's to be preferable to ICSDis. with other radionuclides and

preferable to present day photoelectric detectors. The best available unit for

fire protection was found to be the recently marketed combination detector. The

cost of a combination unit is considerably more than the Am-241 ICSD and data is

lacking on how much more sensitive it is. Therefore, the cost-effectiveness of

combination units compared to Am-241 ICSD's is unknown.

TABLE OF CONTENTS

SECTION PAGE

1 SUMMARY ...................... . ......... . -

1.1 Objective .... ........... 1.2 Approach ...........

1.3 Discussion ..........

1.4 Conclusions ....... ........

2 BACKGROUND INFORMATION ON ICSD's

. .... ............ l-1

*................ 1-2 . . . . . . . . . 1.. 1-4

2-1

2.1

2.2

2.3

2.4

2.5

General Discussion ......... Description of ICSD's.....

Regulations and Guidelines. . • Distribution of ICSD's. "

Description of ICSD Life Span

2-1

2-2

2-5

2-9

2-11

3 ENVIRONMENTAL IMPACT ............

3.1 Benefits. . ...... . .....

3.2 Radiological Impacts of ICSD's

During Their Life Span ......

3.3 Non Radiological Impacts ....

4 ALTERNATIVES .... ............

. . . . . . . . . . . . 3-1

3-1

. . . . . . . . . . . .

. . . . . . . . . . . .

3-12

3-70

. . . . . . . . . . . . 4-1

4.1

4.2

4.3

4.4

4.5

4.6

4.7

4.8

ICSD with Am-241 ............ ICSD with Ra-226 ............

ICSD with Ni-63 ............

Photoelectric Detector• ..

Combination Unit•... . _..... ."Tube Bundle" Detector Systemn

Taguchi Semiconductor Gas Sensor.

Thermal Sensors . . . . . ....

4-1

4-2

4-3

4-6

4-10

4-10

4-10

4-11

5 COST AND RISK VERSUS BENEFIT ANALYSIS . . . . . 5-I 

5.1

5.2

5.3

5.4

5.5

General . .... ...............

Costs........... .. .

Benefit Versus Risk for An-241 ICSD's

Analysis for Alternatives ........

Conclusions .... ..............

5-1

5-2

5-3

5-6

5-12

iii
SECTION PAGE

6 FUTURE PRODUCTS ........... .................... .. 6-1

7 REFERENCES ............ ......................... 7-1

APPENDIX A - TOXICITY OF RESIDENTIAL FIRES ........... ... A-1

APPENDIX B - DOSE CALCULATIONAL METHODS ........... .... B-1

APPENDIX C - RADIOLOGICAL HEALTH EFFECTS .............. C-1

iv
LIST OF FIGURES

FIGURE

2.1 Biopolar Ionization Chamber. . . . . . . . . . ....

2.2 Unipolar Ionization Chamber ...................

3.1 Fire Incident Report ...... .................

3.2 Relation of Age and Sex to Death by Fire -

California 1977 ...... ....................

3.3 Am-241 Alpha Source Foil......... . . . . . .

3.4 Pathways of Exposure Resulting form the

Disposal of ICSD's ........ ...... . ... .

3.5 Major Factors Influencing the Contamination of Air

and Ground Water from Landfill Disposal of ICSD's...

3.6 Examples of Transverse Dispersion Patterns of

Contamination Plumes ......................

4.1 Photoelectric Detector Optics .......... ......

4.2 Detector Sensitivity Versus Particle Size for'a

Light-Scattering Type Detector (S-2) and for an

Ionization Type Detector (R-2) . ...........

5.1 Cost of Dose Reduction for Alternatives versus

Am-241 ICSD. ....... .....................

PAGE

* . 2-6

* . 2-6

• . 3-2

* . 3-6

* . 3-14

* . 3-26

* . 3-31

* . 3-37

• . 4-7

4-9

. . . 5-7

6.1 Distribution of Am-241 ICSD Units - Actual (1972-78)

and Projected (1979-86) ............ ......

6.2 Distribution of Am-241 ICSD Activity - Actual (1972-78)

and Projected (1979-86) ..... ................

6.3 Average Activity per Am-241 ICSO - Actual (1972-78)

and Projected (1979-86) ..... .................

* . 6-4

• . 6-5

• . 6-6

V
LIST OF FIGURES

FIGURE PAGE

A.1 Effects of CO on Man as a Function of Concentration

and Time ......... ......................... ... A-2

A.2 Carbon Monoxide Production from Smoldering Fire-Started

by Cigarette Burning Into Sheet and Mattress .... ....... A-3

A.3 Minimum Escape Time for a Healthy, Clothed Person at

Extreme Temperatures . ... ..... ................. ... A-5

A.4 Deposition of Particles in Respiratory Tract ....... A-6

8.1 Gamma-Ray Spectrum of an Unshielded Am-241 Source

Showing Multiplie X-Ray Peaks (Energy Values in keV) . . . B-2

B.2 Gamma-Ray Spectrum of ICSD Containing 3 uCi

Am-241 Source ......... ...................... B-3

vi
LIST OF TABLES

TABLE PAGE

2.1 Radiological Data for Ni-63, Ra-226

and Am-241 . . . . . . . . . . . . . . . . . . . . . . . .

2.2 Organ Doses for Safety Criteria

Evaluation (1OCFR32.28) ... . . . . ..........

2.3 Distribution of Residential Am-241 ronization

Chamber Smoke Detectors ...... .................

2.4 Distribution of Am-241 Ionization Chamber

Smoke Detectors ...... ......................

2.5 Distribution of Residential Ra-226 Ionization

Chamber Smoke Detectors ...... .................

3.1 Fire Statistics (CFIRS) for California

Residences and Apartments ..... ................

3.2 Property Loss Due to Fire.................. .

3.3 Residential and Apartment Loss Due to Fire -

State of California ..... ....................

3.4 Composition of Municipal Solid Waste

Collected from Four Different CitieS. .............

3.5 A Summary of Problems Reported for 11,781

Unacceptable Land Disposal Sites ............. ...

3.6 Results of Tests in which Am-241 Foils Were

Subjected to Various Corrosive Conditions ...

3.7 Fifty-year Dose Commitments Resulting from Intake

of Contaminated Ground Water and Food Crops . . . ....

3.8 Fifty-year Total Body and Organ Dose Commitments

Resulting from Resuspension of Am-241 in Landfills ....

3.9 Size Distribution of Particles in Incinerator

Stack Gas . .-......................

3.10 Particulate Emission for Incinerators of

Various Designs ....... .....................

3.11 Average Air Pollution Control System Removal

Efficiencies ............ . ..............

2-4

2-8

2-12

2-13

2-14

3-4

3-10

3-10

3-27

3-30

3-35

3-40

3-47

3-50

3-51

3-52

vii
LIST OF TABLES

TABLE

3.12 Summary of 50-Year Total Body and Organ Dose

Committments Associated with Incineration of

One Million ICSD's Containing 3 uCi of Am-241.

3.13 Calculated 50-year Dose Commitments

(Rem) Resulting from Am-241 ICSD Source

Ingestion ...... ...................

PAGE

3-55

3-60

3.14 Fifty-year Dose Commitments for

Individuals Involved in Firefighting

or Cleanup Operations ..... ........

3.15 External Doses Associated with

Manufacture and Distribution of

Am-241 ICSD's .............

3.16 Annual External Doses Associated

with Normal Use and Disposal of

Am-241 ICSD's .............

3-62

3-65

3-66

3.17 Summary of 50-year Total Body and

Organ Dose Commitments Associated

with Am-241 ICSD Disposal .........

3.1.8 Summary of Total Body and Organ Doses

(rem) Associated with Annual Manufacture, Distribution, Use and

Disposal of Am-241 ICSD's . . ....

3.1g Summary of Total Health Effects

Expected from Annual Manufacture,

Use and Disposal of Am-241 ICSD's..

3.20 Summary of Doses and Health Effects

from Manufacture, 10 Years of Normal

Use and Disposal of 14 Million Am-241

ICSO's .. . . . ..........

........... . . . . . 3-67

.................. 3-68

*.... .......... 3-69

QQIQ.O . . . . 3-71

4.1

5.1

6.1

Comparison of Inhalation Dose Commitments Resulting from Incineration of

ICSD's with Different Radionuclides .......... . . . . 4-4

Loss of Life Expectancy Due to Various Causes ........ 5-4

Estimated Future Distribution of Residential

ICSD's . ................... QOOm.O .6-3

viii
LIST OF TABLES

TABLE

B.1 Organ Dose Conversion Factors for

External 60 keV Photon Sources ......

B.2 Fifty-year Dose Conversion Factors for

Inhalation of Ni-63, Ra-226 and Am-241.

B.3 Values of the Clearance Parameters for

the Task Group Lung Model ........

B.4 Fifty-year Dose Conversion Factors for

Ingestion of Ni-63, Ra-226 and Am-241

C.l Spontaneous Cancer Mortality Rates

for the United States .... .........

C.2 Comparison of Health Risk Estimates

As ociated with Collective Dose of

100 Organ-rem ..... ............

C.3 Comparison of Health Risk Estimates

Associated with Internally - delivered

Organ Dose of 106 Rem .............

C.4 Health Risk Estimates Used in this

PAGE

. . . . . . . . B-7 8. 

. . . . . . . . . B-7

. . . . . . . . . B-9

. . . . . . . . . B-10

. . . . . . . . . C-2

. . . . . . . . . C-5

. . . . . . . . . C-6

Report ............ . . . . . . . . . . . . . . . . . C-8

ix
4-
1. SUMMARY

1.1 OBJECTIVE

Since the issuance of the National Environmental Policy Act (NEPA) of

1969, all agencies of the Federal Government are required to prepare detailed

environmental impact statements (EIS) on proposals for legislation and other

major Federal actions significantly affecting the quality of the human

environment. The main objective of these studies is the careful consideration of

environmental aspects of proposed actions. Licensing and regulatory policy and

procedures for environmental protection as related to the NRC are stated In the

Code of Federal Regulations, Title 10, Part 51 (1OCFR51).

At present, the Nuclear Regulatory Commission (NRC) is reevaluating the

adequacy of existing policy dealing with the distribution of consumer products

containing radioactive material. One such consumer product is the ionization

chamber smoke detector (ICSD), which in recent years has become widely

distributed.

The objective of this report is the assessment of the impact of ICSD's

on people and the environment. An assessment of benefits and risks is made for

presently-distributed ICSD's and possible alternatives. The work should prove to

be an important source of information for a generic environmental impact

statement iGEIS) on consumer products containing radioactive material which will

be written in the future.

1.2 APPROACH

The approach to be-followed in this report is to cover all topics

necessary to arrive at a comprehensive assessment of ionization chamber smoke

detectors. First a general overview or background information on ionization

chamber smoke detectors and fire detection is given. A discussion of types of

ICSD's, possible radionuclides used, regulations and guidelines, distribution,

and description of life span activities is included.

1-1
A discussion of the environmental impact of the use of ICSO's follows.

The benefits derived from ICSD usage include the saving of lives and property due

to early detection of fires. The adverse impacts include both radiological and

nonradiological aspects. The radiological impacts are expressed in terms of

health effects from exposures and dose commitments acquired during the life span

of the ICSD's. Included in the discussion of radiological impacts is the

disposal of ICSD's at the end of their useful life. The resulting exposures and

dose commitments are estimated for various disposal scenarios including landfill

and incineration. Possible accidents or misuses of ICSD's are discussed as

potential environmental impacts. Calculated dose and dose comnmitments are

compared to NRC safety criteria as found in the Code of Federal Regulations under

Title 10, Energy

The next section deals with alternatives to present day ICSD's. The

discussion includes reduction of activity in detectors, use of different

radionuclides, and various alternatives such as photoelectric detectors that do

not contain radioactive material.

Having discussed both the benefits and impacts of ICSD's and various

alternatives, a cost-and-risk-benefit analysis is performed to assess the Am-241

ICSD's and the different options available. The assessment is both quantitative

and qualitive in nature.

As a final section, a discussion of future products and trends is

given. Such a discussion is, by nature, qualitative and represents little more

than an educated guess as to future trends and products.

1.3 DISCUSSION

Residential fires continue to pose a major problem in the United

States, ranking as the second most frequent cause of accidental death in the

home. Between 7,500 and 12,000 lives are lost in fires every year with 70

percent of these occurring in residential fires. Residential property loss due

to fires is over one billion dollars annually. A key element in reducing loss of

life and property is early detection of fires. Various devices are available

that detect flames, heat, or products of combustion. In recent years devices

that detect products of combustion have been introduced to the consumer market

and their sales have increased dramatically. These so-called "smoke" detectors

are of two types. The majority have been of the ionization chamber smoke

detector (ICSD) type which contains small amounts of radioactive material. The

1-2
remainder have been of the photoelectric type which contains no radioactive

material. A combination detector has been recently marketed that contains both

an ICSD and a photoelectric detector. Based on theoretical studies and case

histories, the estimated percent of residential fire-related deaths that smoke

detectors could save is between 41 and 89 percent.

Most ionization chamber smoke detectors contain americium-241 (Am-241),

a radioactive substance that emits ionizing radiation. Other radionuclides could

be used in place of Am-241. In the past, radium-226 (Ra-226) has been used in

detectors, but at present it is not employed in the consumer product. Nickel-63

(Ni-63) is presently being studied for use in consumer smoke detectors, having

already been used in commercial applications such as in large warehouses. The

user of an Am-241 ICSO is exempt from regulations, but the manufacturer must

apply for and obtain a specific license from the Nuclear Regulatory Commission to

distribute the product. The license is granted only after the applicant has

demonstrated that the product is designed and will be manufactured in a manner

such that specific requirements and safety criteria are met.

Since 1972-1973, the residential market for Am-241 ICSD's has increased

rapidly. Fourteen million units containing a total of 41 curies of Am-241 were

distributed in 1978 and 26 million units have been distributed since 1972. Based

upon present projections, about 90 million units will be distributed by 1986.

The peak year of distribution should be 1978. The average activity per unit in

1978 was 3 uCi and projections indicate this will become lower in the future.

The distribution of photoelectric detectors has been minimal compared

to ICSD's. Early photoelectric units were not as reliable as comparable ICSD's

because of various reasons, in particular, the use of incandescent bulbs. The

introduction of low-power light emitting diodes has improved their reliability

considerably. The cost of photoelectric units is greater than the cost of

comparable Am-241 ICSD's, basically because of slightly more complex circuitry.

The photoelectric units have been found to react quicker to smoldering or

slow-burning fires while the ICSO's react quicker to fast-burning fires. Both

appear to have responses comparable in terms of saving lives. However, it is

felt the ICSD units may have a slight edge over the photoelectric units since

response is more critical to fast-burning fires.

The nonradiological impacts due to use of both ICSD's and photoelectric

detectors have been determined to be slight and indistinguishable from one

another. For a typical residential Installation, the risk of an occupant being

1-3
exposed to nonradiological toxic products, due to burning for example, is judged

to be extremely small.

The use of Am-241 ICSD's does result in exposure of people to low

levels of radiation. Analysis shows that the manufacture, distribution, normal

use, and disposal of 14 million Am-241 ICSD's each containing.3 uCi of Am-241

will result in a collective total body dose of 1100 person-rem. The useful life

is assumed to be ten years. Disposal is by either sanitary landfill or

incineration. Fourteen million ICSD's will service about 21 million people.

Analysis also shows the risk to the exposed population is about 0.1 fatal cancer.

The normally-occurring cancer mortality rate for the total population of the

United States is about 370,000 per year or about 35,000 per year for a group of

21 million people.

A comparison of these numbers illustrates the relatively small risk

involved in using an Am-241 ICSD. It should be noted the 370,000 cancer deaths

per year are actual deaths while the 0.1 fatal cancer over ten years of ICSD use

was calculated using conservative assumptions. The ratio of the potential lives

saved to the possible fatal cancers due to use of ICSD's ranges from 15,000 to

51,000.

Analysis of potential accidents with Am-241 ICSD's showed the dose

commitments received by maximally exposed individuals to be significantly within

the safety criteria standards required by the Nuclear Regulatory Commission.

Comparative analyses based upon cost, risk, and benefits, found present

day Am-241 ICSD's to be preferable to ICSD's with other radionuclides and

preferable to present day photoelectric detectors. The best available unit for

fire protection was found to be the recently marketed combination detector. The

cost of a combination unit is considerably more than the Am-241 ICSO and data is

lacking on how much more sensitive it is. Therefore, the cost-effectiveness of

combination units compared to Am-241 ICSD's is unknown.

1.4 CONCLUSIONS

Based upon the results of this study, a number of conclusions regarding

ICSD's are stated below.

1. A significant amount of uncertainty exists with respect to the total

1-4
population dose and resultant health effects as determined by this study. Due to

the inclusion of conservatism, however, the results of these assessments are of

value in delineating the upper bound of radiological impact. These assessments

also serve to identify the relative importance of the various activities

associated with ICSD use and disposal as sources of exposure.

2. The sum of doses to the population from the annual production,

distribution, use, and disposal of 14 million Am-241 ICSD's is estimated to be

lower than that which would be expected to result in one cancer death or one

serious genetic effect.

3. The environmental assessment of presently-distributed Am-241 ICSD's

indicates dose commitments much lower than the safety criteria found in 10CFR32

for gas and aerosal detectors.

4. The estimated percent of residential fire-related deaths that smoke

detectors could save is between 41 and 89 percent.

5. The use of Am-241 ICSD's is Justifiable as a means to detect fires and

prevent loss of life and property. The estimated benefit-to-risk ratio for units

containing 3 uCi is between 15,000 and 51,000.

6. The use of Ra-226 in ICSD's is not recommended because of a longer

half-life compared to the half-life of Am-241 and because of the emanation of

small amounts of Rn-222.

7, The use of Ni-63 in ICSD's instead of Am-241 is recommended if the cost

and sensitivity of Ni-63 ICSD's can be made comparable to Am-241 ICSD's. They

are not recommended if their cost is higher.

8. Am-241 ICSD's are cost-effective compared to presently-distributed

photoelectric detectors.

9. The best available unit for fire protection is the combination detector

containing both an ICSD and a photoelectric detector. However, data is lacking

as to whether it Is cost-effective compared to Am-241 ICSD's.

1-5

2. BACKGROUND INFORMATION ON ICSD'S

2.1 GENERAL DISCUSSION

Residential fires continue to pose a major problem in the United

States. They remain the second most frequent cause of accidental death in the

home. The rate per capita is greater in the United States than in any other

industrialized nation. Though fire data is often incomplete and inaccurate ittis

estimated between 7,500 and 12,000 people die in fires annually. Another 300,000

fire injuries are incurred and four to five billion dollars in property is

destroyed(I). Residential fires have been found to contribute significantly to

the loss of life due to fires. The main causes of loss of life are burns and

smoke inhalation. Both burns and smoke inhalation can be avoided if early

detection of fires is practiced. Such detection can be made by the use of

various devices to detect flames, heat, or products of combustion. In recent

years detectors that detect products of combustion have been introduced in the

market place and the sale of such devices has increased dramatically. The

majority of the "smoke" detectors have been of the ionization chamber smoke

detector (ICSD) type, while the remainder have bcon of the photoelectric type.

Both types detect combustion products and hence are given the name "smoke

detectors."

The most widely distributed ICSD contains americium-241 (Am-241).

Because of its dominance on the market place, detectors with Am-241 are

considered in this report as the reference.ICSD. Other ICSD's are and have been

manufactured. In particular, units containing radium-226 (Ra-226) have been

available to consumers. At present in the United States the only other

alternative radionuclide being considered is nickel-63 (Ni-63). As in the cases

of Am-241 and Ra-226 units, Ni-63 has been used in commercially available units.

However, Nt-63 ICSD's have not been sold on the residential market as of this

time. For analysis in this report, Am-241 ICSO's will be considered the primary

detector. All other ICSD's will be considered as alternatives with radioactive

material.

2-1
2.2 DESCRIPTION OF ICSD'S

2.2.1 General Operation

Ionization chamber smoke detectors operate in the following simplified

manner. A source of ionizing radiation is positioned between two electrodes with

an electric potential between them. For present day ICSD's the radiation source

emits ionizing radiation in the form of alpha or beta particles depending upon

the radionuclide used in the detector. The emitted particles create positive

ions by removing electrons from gas molecules along their path. Released

electrons attach to neutral gas molecules forming negativ~e ions. The produced

ions flow toward the appropriate electrodes depending upon whether their charge

is negative or positive. The result is a small current through the gap between

the electrodes. The ICSD electronics detect the level of the current that

normally flaws in the circuit. Should a change in current develop it will be

detected by a discriminate portion of the ICSD circuitry, causing an alarm or

warning signal to be sounded.

.The current in the ICSD can be lowered or hindered by two mechanisms:

(1) ionized particles recombining before reaching the electrodes and (2) transfer

of ionized particles out of the space between the electrodes by air flow. Air

flow through ICSD's is normally not limiting and does not affect the detector

current significantly. The basic hindrance of the current is from recombination

of the ions. Normally the recombination rate in the chamber is at an equilibrium

condition. rhe recombination rate and ion density between the electrodes is

constant.

Introduction of foreign particles such as products of combustion into

the chamber results in ion capture by the foreign particles. The increased mass

of the particles to the ions results in a significantly reduced velocity (the

particle-ion pair compared to the ion alone) and some of the pairs are carried by

air flow out of the chamber before reaching the electrodes, whereby the electrode

current is reduced because of a reduction in charge transfer. When the current

drops to the discriminate level, the alarm is sounded indicating the presence of

foreign particles between the electrodes.

2-2
2.2.2 Radionuclides in ICSD's

Essentially any source of ionizing radiation can be used in an

ionization chamber smoke detector. The selection of a radionuclide for use in an

ICSD by a manufacturer requires considerations of both economics and safety. As

will be outlined in Section 2.3, certain regulations and guidelines govern the

manufacture and distribution of ICSO's. Particular radiation safety standards

must be met. Important considerations in selecting a radionuclide for use in an

ICSD are:

1. Radioactive half-life,

2. Ionization potential,

3. Radiological. consequences, and

4. Cost or availability.

The radioactive half-life is important in establishing the useful

lifetime of an ICSD. Radionuclides with extremely short half-lives cannot be

effectively used. The ionization potential refers to the effective current which

might be generated in an ICSD. Here the problem of using an alpha- or

beta-emitter must be addressed. Am-241 is an alpha-emitter while Ni-63 is 'a

beta-emitter. The third item considered in radlonuclide selection is the

possible radiological consequences during use or misuse. The consequences are

essentially external exposure or internal exposure due to inhalation or ingestion

of the radionuclide. Table 2.1 gives important radiological information on the

radionuclides so far identified as possible sources in ICSD's: Am-241, Ra-226,

and Wi-63. Maximum Permissible Concentrations. (MPC) as defined in 1OCFR20 are

included for comparison sake. The cost or availability of radionuclides in an

appropriate form and enclosure will, of course, greatly affect its selection.

2.2.3 ICSD Design and Construction

The design of ICSD's includes variations in the design of the major

components such as the ionization chamber. Am-241 alpha particles have a mean

range in air at STP of approximately four centimeters. Therefore, within four

centimeters of the Am-241 source, approximately the same number of positive and

negative ions will be created. This will be the case between the electrodes for

Am-241 ICSD's with electrode spacing of four centimeters or less. Such a chamber

2-3
Table 2. 1. Radiological Data for Ni-63, Ra-226 and Am-241.

I.'

Energy of Emission, NOV(Z) most Restrictive 1PC

Half Specific .... . ... Life Activity Other

Radionuclide (Years) (CI/g) Alpha Beta Gamma Radiations Air Water

NI-63 92 62 0.067(100) 2E-9 3E-5

Ra-226 1620 1.0 4.78(95) 0.09,0.17 Rn x-rays daughter 2E-12 3E-8

4.60(5) (both e-) 0.19(4), radiations

trace others from RaI-222,

to 0.6 Po-218.

Pb-214,

Di-214,

Po-214

Am-241 458 3.3 5.49(85) 0.02,0.04 Kp L x-rays daughter 2E-13 4E-6

,5.44(13) e 0.05(all e) 0.06(36). radiations

trace others from Pu-241

to 0.07
is referred to as a bipolar chamber. When electrode spacing is greater than four

centimeters, two regions will exist in the ionization chamber. The region within

four centimeters of the Am-241 source will be similar to the bipolar chamber.

The region beyond four centimeters will essentially have ions of only one

polarity present. A space charge region will separate the tw9 regions and act to

stabilize the ion concentration in the unipolar chamber. Figures 2.1 and 2.2

illustrate the two types of'chambers( 2 ).

ICSO's can also vary according to the number of chambers. Dual chamber

devices essentially have a reference chamber and a measurement chamber. The

reference chamber establishes a current based only on the ambient air (no foreign

material). The measurement chamber establishes the current based on the ambient

air plus any foreign material such as combustion products that may be in the

chamber. A triple chamber ICSD (not presently available on the market) is

designed to obtain the best working point for a detector While compensating for

nonfire conditions. Though designed for beta sources, in particular Ni-63,

triple chamber smoke detectors can be made using Am-241.

The remainder of the ICSD consists of the electronics, power source or

battery, alarm horn, and enclosure. The electronics and power source designs are

fairly standard. The enclosure design is important to the successful functioning

of an ICSD. The design of the enclosure may be based on the following factors:

1. Velocity effects on entry and exit from the unit.

2. Current leakage paths on high impedence components or

insulators in the sensing chamber.

3. Adhesion of aerosol particles to plastic pieces that

have acquired a static charge.

2.3 REGULATIONS AND GUIDELINES

Smoke detectors that contain Am-241 are subject to regulation by the

U. S. Nuclear Regulatory Comtission (NRC). The NRC regulates the distribution of

Am-241 smoke detectors in both Agreement and Non-Agreement States. The extent of

regulation is stated in the Code of Federal Regulations under Title 10, Energy.

Am-241 is -considered to be a byproduct material, which Is defined as many

radioactive material (except special nuclear material) yielded in or made

radioactive by exposure to the radiation incident to the process of producing or

utilizing special nuclear material." Part 30 of Title 10 (1OCFR30) states thd

2-5
(D e

(D

e

e 0

(D

Figure 2.1. Bipolar Ionization Chamber

4

8. 9 9

SPACE

CHARS

4cm

E E)

(D

0 G 0D

F m

Figure 2.2. Unipolar Ionization Chamber 2 .

2-6
rules applicable to all persons in the United States governing domestic licensing

of byproduct material under the Atomic Energy Act of 1954, as amended, and

exemptions from domestic licensing requirements permitted by Section 81 of the

Act.

1OCFR3O.20 deals explicitly with gas and aerosol detectors containing

byproduct material. It states "except for persons who manufacture, process,

produce, or initially transfer for sale or distribution gas and aerosol detectors

containing byproduct material, any person is exempt from the requirements for a

license set forth in Section 81 of the Act .. to the extent that such person

receives, possesses, uses, transfers, owns, or acquires byproduct material in gas

and aerosol detectors designed to protect life or property from fires and

-airborne hazards, and manufactured, processed, produced, or initially transferred

in accordance with a specific license issued..."

In order to manufacture, process, produce, or initially transfer gas

and aerosol detectors, a license is required. 10CFR32 covers specific domestic

licenses to manufacture or transfer certain items containing byproduct material.

Gas and aerosol detectors are covered in Section 32.26., The requirements for

application for a license are outlined including information that must be

supplied by the applicant.

The safety criteria for gas and aerosol detectors are covered in

Section 32.27. An applicant for a license is required to demonstrate that a

product is designed and will be manufactured in a manner such that certain

criteria are met. The criteria are as follows:

1. The external radiation dose in any one year or the dose commitment

resulting from the intake of radioactive material in any one year to a

suitable sample of the group of individuals expected to be most highly

exposed due to the normal use and disposal of a single exempt unit and

to normal handling and storage of expected.,quantities of exempt units

accumulated in one. location during marketing, distribution,

installation, and servicing of the product will not exceed the organ

doses specified in Column I of Table'2.2.

2. Wear and abuse of a product due to normal handling and use during its

useful life will not result in a significant reduction in the

effectiveness of safety features such as containment and shielding.

3. The probability should be low that safety features of the product would

fail under use outlined in criterion 1 such that a person would receive

an external dose or dose commitment in excess of the organ doses

specified in Column 11 of Table 2.2. Low probability is stated to be

2-7
Table 2.2. Organ Doses for Safety Criteria

Evaluation (IOCFR32.28).

Col um Col umn Col umn

I II III

Part of Body (rem) (rem) (rem)

Whole body; head and

and trunk; active

blood-forming organs;

gonads; or lens of eye 0.005 0.5 15

Hands and forearms;

feet and ankles; localized areas of skin averaged over areas no larger

than I square centimeter 0.075 7.5 200

Other organs 0.015 1.5 50

2-8
not more than one such failure per year per 10,000 exempt units

distributed.

4. The probability should be negligible that safety features of the

product would fail under use outlined in criterion I such that a person

would receive an external dose or dose commitment in excess of the

organ doses specified in Column III of Table 2.2. Negligible

probability is stated to be not more than one such failure per year per

one million exempt units distributed.

Smoke detectors which may be produced in the future containing

byproduct material other than Am-241 would have to meet the same requirements and

regulations as given above. Detectors with Ni-63 would fall into this category

since Ni-63 is considered a byproduct material.

Smoke detectors which contain Ra-226 are not regulated by the NRC since

Ra-226 is not byproduct, source, or special nuclear material. Ra-226 is

considered to be a naturally-occurring material and as such is not under

regulation by the NRC or comprehensively controlled by any other federal agency.

The regulation of Ra-226 and other naturally-occurring or accelerator-produced

radioactive materials (NARM) on a state level is non-uniform and incomplete. The

Conference of Radiation Control Directors, which is an organization whose

membership is comprised of all directors of radiation control programs in the 50

states, the territories, and some large municipal agencies, established a Task

Force to develop guidance for the individual state's evaluation of NARM products.

Representatives from State Radiation Control Programs, the Bureau of Radiological

Health (BRH), the NRC, and the U. S. Environmental Protection Agency (EPA) were

on the Task Force. The major output of the Task Force was a set of guides for

NARM materials( 3 ). NARM Guide 3 deals with gas and aerosol detectors and

"provides criteria for the evaluation of gas and aerosol detectors containing

radioactive material which are to be distributed to persons exempt . . ." NARM

Guide 3 applies essentially the same standards to Ra-226 smoke detectors as the

NRC applies to smoke detectors with byproduct material.

2.4 DISTRIBUTION OF ICSD's

Ionization chamber smoke detectors have been used in the United States

since 1951(4). The first detectors used foils containing approximately 20 uCi of

Ra-226 in the form of radium sulphate. In 1963 Am-241 was introduced into the

manufacture of ICSD's. The first specific license to distribute ICSD's was

issued by the Atomic Energy Commission (AEC) on September 17, 1963. The first

2-9
license granting exemption was issued September 5, 1969. The ICSD in this case

contained approximately 80 uCi of Am-241.

Nearly all distributed ICSD's in the early years were used in

commercial installations such as factories, public buildings, and warehouses.

Because of the success of ICSD's in commercial installations and the large number

of fires in home residences, authorities began to study the potential benefits

that ICSD's might have in the home residence. For example, one study by the

National Research Council of Canada, Division of Building Research, researched a

series of dwelling fires in Ontario Province and concluded that 41 percent of the

deaths could have been prevented by installation of ICSD's( 5 ). Cost was the

basic limiting factor for use of commercial ICSD units in homes. Commercial

.units were basically too expensive for use by most homeowners.

Manufacturers were able to bring ICSD's into the consumer product

market by developing single station self-contained units, some battery operated,

and by cutting the cost via mass production. In the past years, the advances in

electronic state-of-the-art and competition among manufacturers and distributors

has lowered prices considerably and ICSD's are essentially affordable by nearly

all consumers. Since about 1972-73, the home or residential market for ICSD's

has increased rapidly. This can be attributed to the above reasons, to

promotion by such groups as the National Fire Prevention and Control

Administration, and by vigorous promotion campaigns by the manufacturers.

The distribution of ICSO's with Am-241 is by far the greatest part of

the market today. Few Ra-226 units arre still manufactured. No Ni-63 units have

been marketed in the home or residential market. Based on data supplied to the

NRC by manufacturers and distributors, Table 2.3 illustrates the dramatic rise in

the use of Am-241 ICSD's in the consumer area. Because all the data reported to

the NRC is not clearly divided into commercial and consumer products, the

information in Table 2.3 was developed by talking to various manufacturers to

determine what products might have been commercial. Table 2.4 illustrates the

total distribution of all (commercial plus residential) Am-241 ICSO's for the

same time frame used in Table 2.3. Included in the data is the number of firms

licensed by NRC to distribute each year. The total activity for all units, the

average activity for all units, the average activity per unit, and the range of

activity per unit are included in both Tables 2.3 and 2.4.

2-10
The past distribution of Ra-226 ICSD's is not as easily quantified as

the Am-241 ICSD's. This is a function of the regulation of products containing

NARM. As discussed in Section 2.3, the regulation of NARM materials is not

comprehensively controlled by any Federal agency and is at the option of the

individual states. For this reason no central reporting agency has compiled data

on Ra-226 ICSD distribution. Contact with agencies such as the Bureau of

Radiological Health and identified manufacturers and distributors of Ra-226

ICSD's resulted in the compilation of a list of Ra-226 ICSD distribution that can

only be considered a best effort, and not a complete list. Table 2.5 illustrates

the compilation of Identified Ra-226 ICSD distribution.

2.5 DESCRIPTION OF ICSD LIFE SPAN

The manufacture, distribution, use, and disposal of ionization chamber

smoke detectors will introduce various segments of the population to ICSD's at

various times and places. No all-encompassing description of ICSO life span can

be made in a manner which is easily used. For this reason, it is necessary to

model the life span by grouping similar events or occurrences. The life span of

ICSD's can be divided into the following basic phases:

1. Manufacture,

2. Storage,

3. Distribution, including sale and display,

4. Installation,

5. Consumer use, and

6. Disposal or abandonment.

The consideration of accidents and ICSD misuse will be made for all

phases of the ICSD life span. The detailed description of each ICSD life span

phase is included in Section 3.

2-11
Table 2.3. Distribution of Residential Am-241 Ionization

Chamber Smoke Detectorsa.

N)

N)

No. Units Total Activity (kCi) Per Unit

Year Distributed Activity (mCi) Average Range

1969-71 393 0.39 1.0

1972 12,800 12.8 1.0 --

1973 92,000 92.1 1.0 0.8-1.0

1974 198,000 247 1.2 0.4-12.2

1975 580,000 3,980 6.9 0.3-12.8

1976 3,040,000 15,600 5.1 0.3-13.7

1977 7,900,000 31,000 3.9 0.3-9.8

1978 14,100,000 40,700 2.9 0.2-8.6

Total 25,900,000 91,600 3.5 0.2-13.7

aData

data

estimated on best available information (NRC distribution

files as of May 1, 1979, conversations with manufacturers, etc.)

A
Table 2.4. Distribution of Am-241 Ionization Chamber Smoke Detectorsa.

!.

No. No. Units Total Activity (pCi) Per Unit

Year Distributors Distributed Activity (mCi) Average Range

1969 1 30 1 35.0 --

1970 1 60,000(est.) 4,690 80(est.) --

1971 3 65,400 5,160 78.9 1.0-79.4

1972 3 121,000 8,380 69.3 1.0-77.6

1973 4 254,000 11,100 43.7 0.8-68.0

1974 7 390,000 9,160 23.5 0.4-46.8

1975 10 821,000 12,200 14.9 0.3-34.2

1976 17 3,360,000 21,700 6.4 0.3-19.0

1977 21 8,060,000 37,300 4.6 0.3-40.2

1978 34 14,200,000 45,600 3.2 0.2-29.5

Total 49 27,300,000 155,000 5.7 0.2-79.4

ft. i ýV - Wi i

aData includes smoke detectors used for residential, industrial,

commercial, and military application.
Table 2.5. Distribution of Residential Ra-226

Ionization Chamber Smoke Detectors.

No. Units Activity (uCi) Total Distribution

Company Distributed Per Unit Activity (mCi) Period

1 12,237 0.15 <2 1968-1974

2 1,000,000 0.05 50 1974-1978

3 10,000 1.00 10 1967-1971

4 1,000 0.75 <1 1974-1976

5 15,000- 0.5-0.75 7.5-15 Before 1977

20,000

6 10,000 1.5 15.0 1972-1975

7 22,000 0.5 11.0 1970-1973

8 804,000 0.05 40.2 1975-1978

9 214,000 0.05 10.7 1970-1976

Total Activity 155

2-14
3. ENVIRONMENTAL IMPACT

3.1 BENEFITS

3.1.1 Saving of Life

Occupants of residences in which an uncontrolled fire commences are

exposed to at least three specific life threatening parameters: toxic gases,

smoke particles, and burning fire (for a discussion of each of these parameters

see Appendix A).

In the United States, between 7,500 and 12,000 lives are lost in fires

each year(l). In 1976 the death toll to victims of residential fires amounted to

approximately 70 percent of the total fire deaths that year. Residential smoke

detectors are presently designed to detect smoke particles In the atmosphere and

warn the building occupants of potential danger. An attempt to estimate the

reduction of residential fire deaths due to the presence of smoke detectors is a

difficult task which must reduce to some form of subjective analysis with large

uncertainties to the final probabilities.

The State Fire Marshall's Office in the State of California has

developed the California Fire Incident Reporting System (CFIRS) to which all

fires are reported that have been attended to by a local fire fighting unit( 6 ) .

An example of part of the fire incident report form is illustrated in Figure 3.1.

As information is developed from these forms it goes on to computer data tapes

for annual analysis of all reported fires within the State. At present, not

enough reports have been completed to the point that sufficient information can

be gathered to accurately appraise the effectiveness of residential smoke

detectors. There does appear to be some impact apparently due to smoke detectors

and the State Fire Marshall has included the following pertinent statement in the

1978 CFIRS annual report:

"The most notable (positive signs) relates to residential

building fires. In spite of a continuing increase in the

number of housing units in the State, residential building

3-1
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3-2
fires have declined for the third year in a row. This,

coupled with 19 percent fewer residential fire deaths (deaths

at the scene), leads us to believe we may be witnessing the

first 1 gng range benefits of smoke detectors in California

houses.'~ 7)

A feeling for the impact that residential fires have on the overall

fire fatality picture can be acquired from *the CFIRS data. Table 3.1 is a

-comparison of injuries and deaths related to fires in dwellings and apartments in

California during 1977 and 1978. During these two years the most significant

change for civilians was the reduction in fire-related deaths. For dwellings and

apartments the number of deaths dropped 22 percent (this differs from the Fire

Marshall statement in that dwellings such as mobile homes, hotels, and such are

not included in Table 3.1). Should this- decline in residential fire-related

deaths continue it could be a significant factor for smoke detectors. In

California the number of residences and apartments equipped with smoke detectors

is estimated to be 20 percent(8). From this it would appear that as more houses

are equipped with some form of smoke detector the reduction in civilian

fire-related deaths should continue.

Although the number of apartments and residences increased in

California between the years 1977 and 1978 there seems to be no increase in the

number of reported building fires. This could be indicating an increase in early

detection of potential fires such that they are being suppressed prior to doing

any reportable harm. This is definitely a problem when trying to determine the

efficiency of smoke detectors in residences, especially when official records are

the only information. base.

While civilian fire-related deaths appear to be on the decline in

California it is interesting to note that there has been little change in the

number of fire-related injuries, both to civilians and fire fighters. It appears

that although the early warnings given by smoke detectors may be responsible for

reduction in deaths, there has been little shift in the percent of injuries

reported for residential fires. This presents an interesting problem in that the

Applied Physics Lab of Johns Hopkins University (APO) has estimated at least an

80 percent reduction in this form of civilian injury along with a 71 percent

reduction in deaths(g). It would seem that as fire-related deaths decrease, so

should -fire-related injuries. Apparently, in California at least, smoke

detectors are having an effect on the number of expected residence fires but not

as great an effect in reducing injuries as might be expected.

3-3
Table 3. 1. Fire Statistics (CFIRS) for California 6,7

Residences and Apartments.

Residential and Apartment Total Number Fires - Percent of all

Fire-Related Building Fires

Incidents 1977 1978 1977 1978

Residential and

Apartment Fires 38,690 38,640 67 68

Civilian Injuries 1,414 1,417 55 57

Civilian Deaths 206 160 60 45

Firefighter

Injuries 869 882 49 47

Flrefighter

Deaths 1 0 50 0

3-4
On the average the residential and apartment fires in California claim

about 56 percent of the total fire-related deaths per year (five-year average).

The age bracket for persons involved in residential fire deaths is illustrated in

Figure 3.2. A significant point here is that within-the age group of 18 to 45

years over 40 percent of male fire-related deaths occur. If smoke detectors

continue to reduce the number of deaths in California this could have significant

impact on the number of families that potentially could lose their main wage

earner. This has far ranging implications and must be considered as an extremely

important point towards the benefits of residential smoke detectors.

To date there have been few reports published which describe the

benefits gained from the presence of smoke detectors during a residential fire

occurrence. The Ontario Housing Corporation of Canada (OHC) has published two

documents which describe the consequence of fires that occurred to corporate

dwellings (81,000 rental dwellings, each containing a single ionization type

smoke detector)(10,11). During the 1978 reporting year a total of 97 fire

incidents were reported with smoke detectors responding to 70 percent *of the

events. In 20 percent of these fire incidents smoke detectors were reported to

be i neffectivye in responding to the event and in 10 percent of the events the

smoke detectors failed to operate because they were defective units (one percent)

or inoperative due to being disconnected by the occupants because of false

alarms. In many of the events where smoke detectors were ineffective the units

sounded but the fire had already been discovered. It might also be noted that of

86,509 ionization chamber smoke detectors serviced by the OHC the overall

defective rate was found to be 2.3 percent. A total of four fatal fires occurred

during the 1978 reporting period and the OHC estimates that smoke detectors

possibly prevented fatalities in 27 percent of all fires that occurred.

In 1976 Rexford Wilson presented a paper to the State of Massachusetts

in which he described the results of an analysis of a study by the National

Bureau of Standards(12). In this paper a Life Safety Index was presented which

weighed the value of heat and smoke alarms in reference to a three minute escape

time. For a smoke detector system in which a detector is installed on each level

of the home, Wilson initially established that 86 percent of the time an alarm

would be sounded before a three minute escape time was lost. These values would

be expected, according to the report, as long as all life saving factors were

optimized. A second paper by Wilson, based on a computer analysis of the

3-5
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Figure 3.2. Relation of Age and Sex to Death by Fire - California 1977.
previous data, indicated a Life Safety Index of 89 percent for an every level

system( 13).

Wilson's value of 89 percent is considered as being optimistically high

by some members of the smoke detector industry but It is a value that is used in

some advertising copy. If the OHC values are reconsidered some support is found

for the Wilson value. Of the 97 fires in the 1978 Canadian study only 67 (70

percent) are considered as detected by the smoke detectors. But, as stated by

Wilson, the Life Safety Index value is dependent upon optimized conditions and

any factors that reduce the maximized parameters will reduce the number (percent)

of lives saved. In the OHC report seven detectors were inoperable, two fires

started in basements where no detectors were located, and five other fires were

detected but were not counted due to circumstances such as smoke detectors

alarming after the fire was detected by the occupant, infirm occupant, or being

ignored even when sounding. Under optimum conditions this would give a total of

81 fires detected which gives an 84 percent alarm rate - a value much closer to

that predicted by Wilson. If the three minute escape value can be related to

possible lives saved an even closer approximation of the Wilson value is found in

the OHC data. In the OHC report, possible lives saved, based on events as they

occurred, is estimated as 26 persons. Four persons lost their lives which gives

a total of 30 individuals involved in life threatening circumstances. This would

give a value of 87 percent (26/30) as the percent of lives saved due to the

presence of smoke detectors. There is no way to prove that the lives of the 26

persons were actually saved by the smoke detector warnings but they all were in

such circumstances that if they did not become aware of the situation in time

they could have lost their lives.

The estimation of the life saving factor for smoke detectors is a

subjective analysis at best. An early (1962) Canadian study, commonly referred

to an the McGuire report, gave an estimation of 41 percent as the expected

reduction in fire fatalities that could be expected due to the presence of smoke

detectors(S). In 1968 the Applied Physics Laboratory of John Hopkins University

published its study of fire fatalities that occurred in a series of fires in the

State of Maryland and Washington, D.C. The APL study indicated a 71 percent

reduction in lives lost if a minimum number of detectors are installed in

accordance with the guidelines set down in Code RFPA-74-1. As with the Wilson

study, the APL values require that all systems are designed, Installed, and

maintained properly and that all occupants respond correctly to an alarm. The 71

3-7
percent reduction in lives lost is considered as that for definite saves. An

even more optimistic value of 86 percent is offered in the APL report when the

"possible lives saved" are added to the "definite saves."

The above data and estimates can now be surmmarized as follows:

0 70% The percent of residential fire-related deaths

among all fire-related deaths in the United States.

* 41-89% The various estimates that have been published

regarding the life saving factor for installation

of smoke detectors.

a 70% The percent of fires detected by smoke detectors in

structures of the Ontario Housing Corporation.

* 87% The percent of lives saved in potential life

threatening situations of the Ontario Housing

Corporation, 100 percent of residences equipped

with smoke detectors.

* 22% The noted reduction in lives lost to residential

fires in California, with 20 percent of residences

containing smoke detectors.

It is still too early in the accumulation of data to establish a life

saving factor for smoke detectors based on actual case histories. The most

extensive records to date are those of the Ontario Housing Corporation. Should

these OHC values hold true for residential and apartment units in the U. S.

there is bound to be a distinct reduction in deaths related to fires in these

dwellings. At the present time the National Bureau of Standards is predicting a

reduction of-50 percent for fire-related fatalities(1 4). It would appear from

the data presently available, that this level of reduction is quite likely to

occur and in time there may be even a greater reduction in residential

fire-related deaths due to the presence of smoke detectors.

For a bottom line estimate as to the life saving benefit of residential

smoke detectors a value of 50 percent reduction in fire related fatalities will

be utilized. Also, an assumption of two-thirds will be used for the eventual

number of residences with functioning smoke -detectors. This would produce a

range of values between 1750 and 2800 for annual lives saved due to the presence

of smoke detectors. This is based on the estimate that 70 percent of fire

related deaths are due to the residential fires and a total annual fire related

death toll between 7500 and 12,000 persons.

3-8
3.1.2 Property Savings

In the United States many fire insurance companies offer a small (one

to two percent) reduction in residential fire premiums when the insured has

installed smoke detectors. A two percent reduction in residential property loss

would amount to an annual savings of approximately $29,000,000(15). That the

fire insurance companies are willing to offer this premium reduction would seem

to indicate that they have some substantial knowledge of the functions of smoke

detectors and their ability to reduce property damage via early warning. A

number *of inquiries into insurance companies, national insurance company

associations, and insurance information associations, revealed that the estimated

reduction in property losses was simply a number "pulled from the air" for a

competitive sales position.

Property loss due to fire can reach staggering proportions in regards

to dollar amounts involved. Table 3.2 is a comparison of monetary loss to

property fires in three advanced countries and serves to illustrate this

point(16). For Great Britain an estimated 50 percent reduction is predicted for

property loss should there be a wide spread installation of smoke detectors. For

Switzerland, the average fire loss has been shown to be reduced by one-third for

buildings with smoke detectors. For the United States, the amount of property

loss is indicated to be $4.17x109 . This figure is higher than the amounts shown

in the Statistical Abstracts for the United States for 1975 (17) but serves to

illustrate the staggering losses that occur due'to-fire. Since 1975 inflation

alone has caused the monetary loss to increase dramatically. This can be

illustrated in data from CFIRS for 1977 and 1978, see Table 3.3. During these

two years the number of residential and apartment fires in California decreased

by 1.4 percent yet the dollar amount of structural damage went up 53 percent,

almost 41 million dollars. It is evident from this that any method of reducing

the potential loss from property fire will lead to large reductions in monetary

loss.

The Applied Physics Laboratory has estimated that the proper

installation of smoke detectors could result in 68 percent reduction in property

loss. This value was based on the analysis of 117 residential fires in the

Maryland/Washington 0. C. area. In the OHC report for 1978 an estimation of

reduction in property loss was made based on a group of residences (81,000)

containing ionization type. smoke detectors. Their findings indicate that a 67

percent (65/97) reduction in property damage occurred that 'year due to the

3-9
Table 3.2. Property Loss Due to Fire.

Country Period Fire Loss

Switzerland 1960-1967 250 x 106 (Swiss Francs)

United Kingdom 1969-1974 860 x 106 (Pounds)

United States 1975 4.17 x 109 (Dollars)

o Table 3.3. Residential and Apartment

State of California.

Loss Due to Fire -

Total Number of Fires Dollar Amount of Loss

Structure 1977 1978 1977 1978

Dwellings 27,655 27,536 55,807,046 82,673,332

Apartments 11,035 11,104 20,801,784 34,797,236

TOTAL 38,690 38,640 76,608,830 117,470,568
presence of the smoke detectors. For Cal iforni a, there appears to be only a

slight drop in number of residential and building fires but this, in fact, may

not be so. It must be remembered that for California, there is a very large

annual increase in dwelling structures, all of which, by law, must be equipped

with smoke detectors. When this is considered it appears that there has been a

larger reduction in dwelling fires in California than the 1.4 percent as

indicated.

From the scant amount of available data, as presented above, it appears

that residential smoke detectors are playing a definite role in reducing property

loss due to fire. A summary of the estimated or actual observations follows:

a 50% - Great Britain - Estimation

* 33% - Switzerland - Measured

* 68% - APL - Estimation

o 67% - OHC - Measured

The percent of homes that will eventual~ly have functioning smoke

detectors is not known. This factor must be combined with the estimate for

reduction in loss upon installation of smoke detectors to reach an estimate of

the impact of these fire warning systems. Other factors exist which will

influence the estimate of property loss reductions. The major factor here is the

number of fires that are signaled by the smoke detectors, subsequently

extinguished, and never reported by the residential occupant. If we assume that

eventually two-thirds of the residences in the United States have functioning

smoke detectors, we could make the following estimates as to the eventioal

potential dollar amount of residential property savings, based on the range of

reductions indicated above:

$1.4 x 19x 0.33 x 0.67 = $310 x 106

$1.4 x 109 x 0.68 x 0.67 =$638 x 106

This savings, from $310,000,000 to $638,000,000 is based on the amount

of residential fire losses for the United States for 1976(15). As numbers of

houses and inflation continue to increase, so will the dollar amount of the

3-11
potential savings with the installation of smoke detectors. Again as with lives

saved, there are hidden savings in such things as reduced calls to the fire

department, paramedics, hospital and medical costs, work and wages, and a host of

others that can quickly add substantial amounts to this dollar figure. It would

appear, as a conclusion, that with a functioning system and correct response of

residential occupants, there will be substantial property savings with the

installation of smoke detectors.

3.2 RADIOLOGICAL IMPACTS OF ICSD'S DURING THEIR LIFE SPAN

3.2.1 General Approach

The radiological impacts of ICSD's must be summed over their total life

span. For normal usage the radiological impacts will be from external doses to

exposed individuals and from inhalation or ingestion of the radioactive material

where possible. In order to evaluate the radiological impacts, the dose to the

maximally exposed individual and the collective dose to the exposed population

are reported for each specific life span activity. The maximally exposed

individual is defined as the individual who receives the largest dose or dose

commitment of any person in the exposed population associated with the specific

life span activity. All assumptions regarding the maximum individual are

outlined In each section to follow.

For dose commitments resulting from inhalation or ingestion of

radionuclides, 50-year dose commitment factors are utilized. Fifty-year dose

commitment factors relate the dose an individual will receive as a result of

retention of radioactive material in the body during the fifty years following

the intake. Estimates of dose commitments to the major organs as determined by

the radionuclide inhaled or ingested are made where appropriate. The

calculational methods used to estimate doses are described in Appendix B.

The following sections describe the processes Involved, people

Involved, and assumptions made in order to estimate dose and dose commitments

during each life span activity. A summation of all data is given following the

life span sections. Only the reference ICSD, namely the Am-241 unit, is

considered in this section. Alternative ICSD's with Ra-226 and Ni-63 are

discussed in Sections 4 and 5; Where collective or average individual doses are

3-12
assessed, the average activity per ICSD is taken to be 3 uCi. In some instances,

however, 5 uCi per detector is used in order to assess doses to maximumly exposed

indi vi dual s.

In the broad, sweeping series of assessments presented below, it is

evident that lack of specific information exists concerning many important

factors. Thus, assumed values are employed in a number of calculations. Every

effort has been made to use values which are best estimates, and which, if in

error, are erroneous on the conservative side. Also' the reference cases which

are analyzed are considered reasonable scenarios. However, should. better

information become available for incorporation into these assessments, the

results can easily be adjusted in either direction to reflect these calculational

refinements.

3.2.2 Manufacture

The manufacture of Am-241 ionization chamber smoke detectors

essentially involves two processes by which occupational doses are possible. The

first process involves the manufacture of the Am-241 source used in the ICSD.

The second process involves the actual manufacture of the ICSD itself.

The Am-241 alpha sources are essentially a rolled foil with the Am-241

contained in a gold matrix sealed between a silver backing and a thin gold alloy

cover. The radioactive americium is in an oxide form, AmO2 . The following

discussion pertains to one manufacturer, but is considered appropriate to all

manufacturers.

The manufacture of the alpha sources starts with AmO2 being uniformly

mixed with gold and formed into a briquette. The briquette is sintered at above

8000C. The briquette is then mounted between a backing of silver and a front

cover of gold and sealed by hot forging.

The composite briquette is then cold rolled in several steps until the

required active area is achieved. The result is the gold cover ends up about

0.002-0.003 mm in thickness and the total piece thickness is 0.2 mn. The strips

normally are 20 mn wide and cut into 1 m long pieces. Figure 3.3 illustrates one

manufacturer's alpha source foil(18).

Sources are then made by either cutting strips from the foils or by

punching them out. When strips are cut, they are usually between 1 and 3 mnm

3-13
A - COVER LAYER

B - ACTIVE LAYER

C - BACKING LAYER

D - SUBSTRATE

A - GOLD - PALLADIUM ALLOY 0.002MM

B - AMERICIUM OXIDE PLUS GOLD 0.002MM

C - GOLD 0.001MM

D - SILVER 0.20MM - 0.25MM

Figure 3.3. Am-241 Alpha Source Foil. 18

3-14
wide. They are fixed to metallic or plastic holders by mechanical means such as

crimping, soldering, welding, or by using epoxy glues.

Most sources, however, use a circular disc 5 mm or more in diameter.

These discs are punched out of the foil sheets. Normally the discs are mounted

in metal holders with a thin metal rim which can be rolled over to seal the cut

edges completely.

The sources are then either placed in a smoke detector ionization

chamber designed by the foil manufacturer and sold as a unit or sent to ICSD

manufacturers for incorporation into their own chamber designs.

The general case Involves ICSD manufacturers receiving the sources

either simply as discs or in holders (at present nearly all are in holders). The

workers who manufacture the ICSD's can be classified into two groups: (1) those

who handle the sources and (2) those who work on the product which has the source

already in an ionization chamber. Both groups may be exposed, but the first

group has a higher chance of being exposed.

Exact numbers on actual exposure data are not easily reproduced for the

manufacture of foils and smoke detectors. Estimates must be made in order to

arrive at adequate values to assess the occupational exposures.

Conversation with one manufacturer of Am-241 foils revealed a

cumulative external dose of 0.8 person-rem per curie of Am-241 processed in 1977.

Approximately 150 workers were involved and the total amount of Am-241 used was

16.6 curies. The maximum dose for an individual was approximately 800 mrem.

Another manufacturer reported 0.2 person-rem per curie of Am-241 processed in

1977. In order to account for the possibility of higher collective doses in

other years, the exposure rate was assumed to be one person-rem per curie of

Am-241 processed.

For 1978, with 14.1 million detectors distributed, containing a total

of 40.7 curies of Am-241, the total dose is found to be 41 person-rem during the

manufacture of the Am-241 foils. It is assumed the exposure occurs while the

foils are being stamped and cut, washed, weighed, and installed in housings where

appropriate.

Internal exposure data on workers is not available. However, the

practices utilized as required by the NRC to manufacture Am-241 makes the

potential for internal contamination small. Discussion with one manufacturer

indicated workers wear shoe covers, lab coats, and gloves. Weekly wipe tests of

floors, counters, etc., are performed. -All employees were given a general

3-15
indoctrination presentation including radiation exposure information upon

employment.

During the manufacture of the actual ICSD units workers are exposed to

the units during various operations or tasks. As mentioned earlier, there are

basically two groups: (1) those that handle the sources and (2) those that work

on ICSD construction and testing. Observation of the assembly of ICSO's by two

manufacturers was made and these two groups were evident. The use of conveyor

belts and modern assembly techniques passed the ICSD's in various stages of

completion past the assembly workers.

Because of the low exposure level from individual sources

(1.2x10" 2 uR/hr per uCi at one meter for an unassembled or uncovered ICSD) the

external exposures expected at a manufacturer's facility are low. Conversation

with one manufacturer revealed the yearly (1978) external dose to individual

badged workers was as follows:

40% No measurable dose

40% Less than 100 mrem

15% Between 250 and 500 mrem

4% Between 500 and 750 mrem

One Individual Between 750 and 1,000 mrem

These numbers correspond to a collective dose of 2.7 to 8.8 person-rem. The

range is given to correspond with the manner in which the doses are reported.

Smith et al.(19) estimated the collective external dose for the entire

ICSD industry during manufacture by using data reported from three manufacturers.

One company used a factor of 2.05 in estimating doses to unbadged workers

compared to badged workers. Based on this number, the total corresponding dose

to unbadged workers for the above data is 5.5 to 18 person-rem. The amount of

Am-241 processed by the manufacturer was 22.5 Ci for 1978. The total activity in

all ICSD's with Am-241 was 40.7 Ci for 1978. Therefore, using the above

assumptions the total occupational dose accumulated in the ICSO manufacturing

industry in 1978 has a range of 15 to 48 person-rem. A value of 48 person-rem

will be used in this report. The maximum dose for an individual is taken to be

1,000 mrem. This is based on the badge data given above. It is noted here that

3-16
the one individual receiving the dose between 750 and 1,000 mrem may have

received the dose from other sources, such as a dentist, doctor, etc. The total

dose was received in a short time (one reporting period) according to the

manufacturer. It is extremely unlikely the dose came from Am-241 foils.

3.2.3 Manufacture Warehousing/Storage

The ideal situation for a manufacturer is not to have to store any

final products in their warehouses. This ideal situation, however,. is very

seldom ever achieved. Storage of goods is norm,ally required for a short time

period. The occupational doses resulting from storage operations has already

been included in the previous section.

3.2.4 Distribution

The distribution of ICSO's is similar to the distribution of any

consumer product. Once the product leaves the manufacturer, it must be

trahsported to various locations for storage and/or local distribution. For

retail sale, the product will end up in storage and eventually be sold to the

consumer. Some products will. end up going to what is identified here as

contractor sales. For ICSD's this is the market in which new homes in locales

requiring smoke detector installation are being built. The contractor may buy

the ICSD's in large quantities. This code market is approaching two million

units per year.

It is important to indicate at this point that not all ICSO's

distributed in the United States are manufactured here. Some are imported from

abroad and then distributed in the United States.

3.2.4.1 Transportation

Because of the complexity of the transportation matrix associated with

ICSD distribution, both in terms of exposure times and geometries, it is not

possible to model the exposures from this mode in any easy fashion. Study has

led to the conclusion that the methodology used by Smith, et al.( 19 ) is as

acceptable as can be found. That approach is repeated here. The Final

Environmental Statement on the Transportation of Radioactive Material by Air and

3-17
Other Modes( 20 ) is intended to serve as background material for regulations

dealing with transportation of radioactive materials. The report goes into

detail on many forms of radioactive materials that are transported. The report

states ". . . assessment of the environmental impact of radioactive material

transportation requires a detailed knowledge of the package types, the principal

transport modes, the number of packages transported per year, the average

quantity of material per package, the average 'transport index' or 'TI' (a

measure of the external radiation level), and the average distance traveled per

shipment." One TI is defined as being equal to 1 mrem/hr at 3 ft from the surface

of a package containing radioactive material. In order to make the assessment

more manageable, a list of "standard shipments" was compiled and given in the

report.

The estimated total TI for limited shipments, which would include

ICSD's, for 1975 was estimated to be 7740. The total collective dose for these

limited shipments was found to be 63.3x10- 3 person-rem.

The dose rate at one meter from an assembled ICSD is assumed to be

8.0x10- 3 uR/hr or 7.4x10"3 urem/hr per uCi of Am-241. In 1978, the total amount

of Am-241 distributed in residential ICSD's was found to be 40.7 curies. A total

transport index for 1978 ICSD distribution can be formulated by taking the total

Am-241 distributed times the dose rate at one meter. The total transport index

is equal to

(40.7 Ci)(106 uCi/Ci)(7.4xlO" 3 urem/hr-uCi)(iO-3 mrem/urem)

(1 mrem/hr-TI)

= 300 TI.

In practice, the actual dose rates would be much lower due to the presence of

packaging. However, for this analysis 300 TI's will be used. Therefore, the

estimated collective dose due to 1978 shipment of Am-241 ICSD's is

(63.3x10" 3 person-rem)(300 TI)

(7740 TI)

= 2.5x10"3 person-rem.

3-18
3.2.4.2 Distributor Warehousing

The exposures resulting from distribution warehousing and storage

activities are estimated in this section. The reference case involves a

warehouse which stores 1,000 units at a time and employs 20 workers. If the

average turnover time for this amount of detectors is 50 days, almost 2,000 such

warehouse operations would be needed to account for an annual sale of 14 million

units.

The exposure rate at three meters from an array containing up to 1,000

ICSD's (3 uCi per unit) is estimated to be about 0.25 uR/hr. (The basis for this

estimate is given in Section 3.2.4.3.) If each worker spends 2,000 hours per year

at an average distance of three meters from this array, the dose to the total

worker population would be about 20 person-rems. The average individual dose

would be about 0.5 mrem. This average dose is undoubtedly on the conservative

side since few, if any, of the warehouse workers would spend most of their time

in such close proximity to the detector array. However, the values arrived at in

this assessment serve to illustrate the fact that, even for worst-case

situations, exposures to the distributor warehouse population are minimal.

3.2.4.3 Retail Sales

This section assesses the radiological impact associated with the

display and purchase of ICSO's in retail outlets. Two specific cases are

analyzed:

1. The dose to store workers and shoppers resulting from an

array of displayed ICSD's, and

2. The dose to a consumer who purchases an ICSD and carries it

on their person for one hour.

Peterson(21) has measured exposure rates from horizontally and

vertically stacked arrays of ICSD's, each containing 5 uCi Am-241. He found that

the maximum exposure rate occurred from 17 horizontal and seven vertical

detectors, and that the total exposure rate was about a factor of three greater

than the maximum value obtained from readings observed for individual detectors.

3-19
These results cannot be conservatively applied here, however, since exposure

rates from a rectangular array would be expected to be greater.

Smith, et al.( 1 9 1 has calculated an exposure rate of 0.3 uR at two

meters from a stacked display containing up to 100 detectors. General Electric

Company( 2 2 ) conservatively estimated the exposure rate at one meter from a

stacked array of 384 units containing a total of 1.15 mCi Am-241 to be 1.5 uR/hr.

This assessment assumes that the exposure rate at one meter from a retail store

array is 1 uR/hr, decreasing to 0.5 uR/hr at two meters, and 0.15 uR/hr at three

meters.

The dose to a maximum individual consumer is assessed by assuming that

the person spends 0.5 hr at one meter from a stacked array of ICSD's, and then

carries two purchased units (5 uCi Am-241 each is used for maximum individual

assessment) at a distance of 10 cm for 0.5 hr. The total body dose in such a

scenario would be about 4.2 urem.

The population dose is assessed by assuming that, on the average, the

entire population spends 0.25 hr at two meters from an ICSD display, and that 14

million purchased detectors (3 uCi Am-241 each is used for average individual or

population assessments) are carried at a distance of 25 cm for 0.5 hr. This

results in a total body dose of 28.1 person-reins to the population from the sale

of ICSD's during a peak year.

The dose to retail clerks working in the vicinity of an ICSD display

can be assessed by assuming an average distance of three meters over a period of

2,000 hours. This results in an individual dose of about 0.5 mrem. If one clerk

was exposed in such a manner for every 1,000 detectors sold, the total dose to

this group of people in a peak sales year would be about seven person-reins.

3.2.5 Use By Purchaser

This section assesses the radiological impact of ICSD use including

transport, installation, testing, maintenance, and operation.

A- Transpor-t

The amount of radiation received by the consumer in the process of

transporting the purchased ICSO's home depends on source strength, duration of

transport, distance. from the source during transport, and amount of intervening

3-20
shielding. This assessment assumes that the purchaser transports two units, each

containing 3 uCi Am-241, at an unshielded distance of one meter for a duration of

one-half hour.

Utilizing the exposure rate constant at one meter for Am-241 in ICSD's

(8.0-x10"3 uR/hr-uCi), the whole body dose contribution from this activity would

be

(6 uCi)(8.Oxlo0 3 uR/hr-uCi)(0.93 urem/uR)(0.5 hr)

2.2x10" 2 urem.

Assuming that, on the average, one person is exposed under similar

conditions for each detector sold, the collective dose resulting from the

transport of the number of ICSO's purchased during a peak year (14 million) would

be

(14x10 6 ICSD's)(1.lxlO"2 urem/ICSD)(0.5 person-hr)

0.15 person-rem.

3.2.5.2 Installation and Operation

Activities related to the normal use of ICSO's which warrant

radiological assessment are installation, operation, and testing and maintenance

activities, including changing batteries and cleaning.

The installation of ICSD's in residences is assessed by assuming an

average installation time of one-half hour and an average source-to-body distance

of 50 cm. The resultant dose to an individual per ICSO would be

(3 uCi)(8.OxlO"3 uR-m 2 /hr- uCi)(0.5 hr)(O.93 urem/uR)

(O.Sm) 2

3-21
= 4.5x10"2 urem.

The installation of 14 million ICSD's would result in a total body population

dose of about 0.6 person-rem..

The dose to the hands of the installer can be estimated by using the

results of contact exposure rate measurements reported by General Electric

(22) Company . The maximum surface exposure rate was found to be 1.3 uR/hr for an

ICSD containing 3 uCi. Thus, the hand dose would be about 0.6 urem per unit

installed. The corresponding hand dose to the population resulting from the

installation of 14 million units would be about 8.4 person-rem.

The average annual individual dose and the dose to the population

resulting from normal ICSD operation are assessed based on the following

assumptions:

1. 100 million detectors with an average activity of 3 uCi are

installed in 50 million residences.

2. 90 percent of the detectors are installed in hallways and ten

percent in bedrooms.

3. Two people are exposed to each bedroom-mounted detector for

eight hours per day at an average distance of 3 m.

4. Three people are exposed to each hallway-mnunted detector for

one hour per day at an average distance oC 2 mu

The annual whole body dose to an individual (D iin urem/yr) would be

0b 0h

d b d h

where

A = Average Am-241 activity per detector (uCi),

0 = Occupancy factor in bedroom,(hr/yr),

0 = Occupancy factor in hallway (hr/yr),

db = Average source-to-subject distance in bedroom (m),

dh = Average source-to-subject distance in hallway (m);

3-22
r = Exposure rate at one meter from an Am-241 source within an ICSD

(8.0x10" 3 uR-m 2 /hr-uCi), and

k = Constant relating dose rate in tissue to exposure rate

in air(O.93 urem/uR).

Thus, assuming the individual has one detector in both the hallway and bedroom,

the annual dose would be

(8.OxlO3 uR-m 2 /hr-uCi)(3 uCi)(o.93 urem/uR)( 92 hryr + 4 m 2

9 m2 4my

=9.3 urem/yr.

.The collective dose to the population (D in person-rem/yr) is given by

o r nk nbnb 0 b n h nh 0 h

p db dh

where

n b

nhp

= Number of

=. Number of

Number of

= Number of

detectors in bedroom,

detectors in hallway,

people exposed per bedroom, and

people exposed per hallway.

Based on the

as follows.

assumptions listed above, the annual population dose is calculated

rAk = (8.0O04" 3 uR-m 2 /hr-uCi)(3 uCi)(0.93 urem/uR)

(2.2x10- 2 urem-m2/hr)(10 6 rem/urem)

3-23
= 2.2x10-8 rem-m2/hr.

Therefore, (2.2xi0-8 rem-m2 /hr) ((lOxl06)(2 people)(2920 hr/yr)

9 M2

+ (90x10 6 )(3 people)(365 hr/yr)

4 m2

= 695 person-rem/yr.

In order to assure reliability and to prevent spurious alarms, smoke

detectors must be periodically checked for proper operation, cleaned, and in some

cases have the batteries replaced. It is assumed here that activities such as

these will result in user exposures averaging one hour per year at a distance of

0.5 meter. The resultant dose to an individual possessing two units would be:

(8.0x10- 3 uR-m 2 /hr-uCi)(6 uCi)(0.93 urem/uR)(1 hr)

(0.5m) 2

= 0.18 urem/yr

The dose to the hands in the above case would be about 1.2 urem/yr.

The whole body dose to the population resulting from the testing and

maintenance of 14 million ICSD's would be 1.3 person-rem. The associated hand

dose to the population would be about 17 person-rem.

3.2.6 End of Life (Disposal)

Since little information exists concerning the rate at which ICSD's may

be returned to the manufacturer for proper disposal, the environmental impact

resulting from normal disposal of ICSD's (e.g., incineration or burial) must be

assessed. Figure 3.4 schematically presents the pathways by which ICSD disposal

3-24
activities may result in external or internal human exposure. These pathways of

exposure are assessed in the following sections.

3.2.6.1 Disposal with Refuse

It is estimated that as many as 100 million smoke detectors may be sold

during the peak sales decade of 1977 to 1986(23). Assuming for the sake of

analysis that all of these detectors are ICSD's, and that these detectors have an

average useful life of ten years, ICSD's would be disposed of at a rate of up to

ten million units per year for several years after the peak sales period. The

disposal rate will gradually decline in the ensuing years reflecting the decline

in sales after the peak years of 1978-79. It is also assumed that the average

activity per unit will be 3 uCi for Am-241 detectors.

3.2.6.1.1 Municipal Solid Waste Practices

Municipal solid waste from residential, commercial, and institutional

sources amounted to 130 million metric tons in 1976 (1.8 kg per capita), and the

yearly total is expected to increase to 180 million tons by 1985(24). The

composition of municipal refuse varies widely, but a typical composite has been

summarized in Table 3.4. Most of thesewastes are collected and transDorted to a

processing or disposal site. Approximately nine percent of municipal refuse is

incinerated, seven percent is recycled, six percent is disposed of in sanitary

landfills, and less than one percent is used for producing compost. The largest

fraction of municipal solid waste, approximately 78 percent of the total amount

collected, is deposited in open dumps which do not meet the minimum

qualifications of a sanitary landfill( 24 ' 2 6 ' 2 7 ). A significant amount of the

solid waste generated is not collected but rather is disposed of in apartment

house, institutional or backyard incinerators, in sewer systems or in

unauthorized dumping areas. This is apparent due to the fact that in certain

urban areas the amount of waste collected per capita is significantly less than

the estimated amount of per capita generation( 27 ). Municipal waste only accounts

for about seven percent of the total volume of solid waste generated nationally.

Agricultural wastes such as animal carcasses, manure and crop harvesting residues

account for about 59 percent of the annual generation, while mineral wastes such

as mill tailings and slag represent 31 percent of the waste. The remaining 37

3-25
Discarded

ICSD's

Refuse KNafbcturer 1614W

Sou, cI e Proper oMaufacturer Disposal

Ccaiost Resource

€,J Int Production Recovery incineration

DIeposition Aironm CQtro

SAuleeses Release$

(nSanItary III

PAResidue or ImWIAL EiDWU S"mt Slg

Figure 3.4. Pathways of Exposure Resulting from the Disposal of ICSD's.
Table 3.4. Composition of Municipal Solid Waste 25

Collected From Four Different Cities.

% Composition of Municipal Waste

Item Range Average

Paper 40-54 45

Wood 1.5-3.5 3

Plastic 2-3 2.5

Glass 3.5-10 6

Metal 7-13 9

Stone, sand 7-8.5 7.5

Organics (food and yard wastes) 20-27 22.5

Rags 1.5-8 4.5

3-27
percent is due to waste generation in the manufacturing industry( 4 1 ). Although

70 to 80 percent of these industrial wastes are disposed of on the generator's

property, a significant fraction will ultimately be desposited in landfills with

municipal wastes(2 4 . The individual steps in the practice of waste collection,

processing and disposal are discussed separately below with regards to their

importance as pathways of exposure.

3.2.6.1.2 Collection

Approximately 175,000 people and 138,000 vehicles are directly involved

in the practice of municipal solid waste collection in this country. Of these

vehicles, approximately 78,000 are of the large, compactor variety while the

remaining 60,000 are classified simply as vehicles other than compactor trucks.

An additional 165,000 operators and 115,000 vehicles are involved in the

collection of industrial wastes( 2 4 2 7 ).

It is difficult to conceive of any credible scenario which could result

in significant exposure of solid waste operators to ionizing radiation as a

result of the collection and transport of ICSD's in municipal refuse.

Considerable shielding from the gamma radiation, the levels of which are Tow even

without shielding, would be provided by the steel walls of the truck bin as well

as the contained refuse. Compaction of the trash could increase the margin of

protection by increasing the degree of shielding and the distance between source

and operator.

The dose to the municipal waste collection population can be assessed

by assuming the following:

1. The number of ICSD's collected annually is ten million with

an average activity of 3 uCi per detector.

2. The averaged time that a collected ICSD spends in a truck is

two hours at an average detector-to-operator distance of two

meters.

3. An average shielding factor of 0.5 is used to account for

attenuation by the truck bin, other refuse, etc.

4. The waste collection population consists of 175,000 people

and 138,000 vehicles, or an average of 1.3 persons per

vehicle.

3-28
The total activity collected per year would be 3x10 7 uCi or 220 uCi per

vehicle. The annual exposures assocfated with each vehicle would be:

(220 uCi)(8xlO" 3 uR-m 2 /hr-uCi)(O.93 urem/uR)(2 hr)(1.3 persons)(0.5)/(2 m)2

0.5 person-urem/yr

= S.Ox10 7 person-rem.

The average annual individual dose would be about 0.4 urem. This

represents a collective dose to the refuse collection population of about 0.07

person-rem.

It is not possible to quantitatively assess the magnitude of the

internal exposure hazard, if it does indeed exist, posed by the collection of

ICSD's in refuse. It would seem, however, that this hazard would be minimal due

mainly to the high degree of Am-241 source integrity which is maintained under

normal and stress conditions. Waste packaging, compaction and coverage by other

refuse would also tend to minimize the possibility of internal exposure.

3.2.6.1.3 Disposal in Landfills

According to a 1976 EPA report to Congress on the effects of waste

disposal practices on ground water, municipal wacXes in the U. S. are currently

disposed of in about 18,500 land disposal sites, only about 20 percent of which

are considered "authorized"(2 g). Only about 20 sites are lined and only 60 or so

have provisions for leachate control. Most of the 18,500 sites are open dumps

which are unacceptable because of burning, water pollution, lack of daily cover,

or some combination of these factors. Only about six percent meet the minimum

requirements for bei-ng considered a sanitary landfill. Table 3.5 summarizes the

results of a national survey of land disposal site problems. Of the total sites

surveyed, 93 percent had insufficient or no daily cover, 84 percent burned some

of their waste, and 45 percent had an existing or potential water pollution

problem. Most of these sites also received some industrial wastes.

The disposal of ICSD's in solid waste landfills can result in the

exposure of population groups through direct radiation exposure, ingestion of

contaminated ground water or food crops, and inhalation of resuspended

radioactivity (Figure 3.5). Due to the dilution of ICSO's in *large amounts of

3-29
Table 3.5. A Sunmary of Problems Reported for 11,781

Unacceptable Land Disposal Sites. 2 7

Problem Number of

Sites Percent

No cover 1,046 8.9

Burning 304 2.6

Water pollution 320 2.7

Burning and no cover 5,393 45.8

Water pollution and no cover 764 6.5

Burning and water pollution 199 1.6

Burning water pollution and

no cover 3,755 31.8

11,781

3-30
Figure 3.5. Major Factors Influencing the Contamination of Air

and Ground Water from Landfill Disposal of ICSD's.

3-31
other waste and/or cover materials, the low levels of penetrating radiation

emitted by detector sources, and the absence of persons in close proximity to a

landfill site for long periods of time, direct radiation should not be considered

a significant mode of exposure. The ingestion and inhalation pathways are

assessed separately below.

3.2.6.1.3.1 Groundwater Contamination

Municipal waste disposal in landfills can result in groundwater

contamination through the generation of leachate formed when water percolates

through cover material and refuse. Precipitation which falls on the site can

either run off, return to the atmosphere by evaporation or transpiration, or

infiltrate the landfill. Surface runoff from surrounding areas, moisture

contained in or produced by the decomposition of the refuse, and water entering

the landfill from the bottom or sides also contribute to the generation of

leachate. The problem of ground water contamination by landfill disposal

practices is compounded by the frequent location of landfills or dumps at sites

which are particularly susceptible to this type of contamination. Examples of

such contamination - prone sites are marshlands, abandoned sand or gravel pits,

old strip mines or limestone sinkholes. The EPA estimates that 70 percent of the

municipal solid waste landfill sites are in ground water surplus areas, and that

the average infiltration of precipitation is ten inc-es per year. Thus, assuming

that the average site comprises an area of 25 acres, the total estimated leachate

generation is 90 billion gallons per year, most of which enters the groundwater

system( 2 9 .) 

Contaminants that have entered the ground water can move horizontally

or vertically, depending on the comparative density and natural flow pattern of

the water in the aquifer. The contaminants do not mix readily with native water

but tend rather to move as a well-defined slug or plume. The concentration of

contaminants in ground water are usually reduced with time and distance by such

mechanisms as adsorption, ion exchange, dispersion and decay( 29 ).

Almost half of the U. S. population depends on ground water for

drinking water supplies. The U. S. Geological Survey estimates that the total

withdrawal of ground water for domestic purposes in 1970 was 9.4 billion gallons

per day (35.6 million m3 /day)( 29 ). Of this amount, it is estimated that five

percent (470 million gallons per day) Is used for drinking and- six percent (564

3-32
million gallons per day) for kitchen use. Most domestic water is Used for

flushing toilets (41 percent) and for washing and bathing (37 percent)( 3 1 ). An

additional 44.6 billion gallons per day (169 million m3/day) was withdrawn from

ground water sources in 1970 for irrigation purposes. Although the total ground

water withdrawal is expected to more than double by the year 2020, the domestic

use portion of the ground water supply will grow approximately at the same rate

as the population(29)

The environmental health impact resulting from the contamination of

ground water by disposal of ICSD's in landfills is assessed below in three

different ways. The first assessment is a straightforward calculation, based on

conservative assumptions, of the transport of ICSD source contaminants from the

landfill to the ground water system to man. The second assessment is the method

used by Johnson( 32 ) in which he compares resultant Am-241 levels in soil and

water with those of naturally occurring Ra-226. Wrenn(33) has assessed the

Am-241 disposal impact by comparing the return to people via diet with the

dietary intake of Am-241 fallout from atmospheric weapons tests. The latter two

assessments employ methods and assumptions which are somewhat different than

those used in this report. Their results are included for the sake of

comparison.

An accurate calculation of the transport of Am-241 contamination from

landfill to man, and the subsequent radiological impact, is not possible due to

lack of specific data concerning many important factors. Although the mechanisms

involved are fairly well-understood, a large degree of uncertainty exists in the

quantitative aspects of source leaching, transport in soil and water systems,

plant uptake, and deposition, translocation and elimination processes in humans.

A conservative utilization of the available data, however, can be applied to

yield an upper bound or "worst case" estimate.

In the ground water contamination pathway, the first mechanism of

importance is the leaching of contamination from ICSD sources. Long term

exposure of Am-241 sources to corrosive environments has indicated that

deterioration of the foils is linked to corrosion of its silver backing and that

the effect increases with the activity loading of the foil( 18 ). However, even

sample foils near the maximum activity loading used in ICSO's showed very slight

leakage. The greatest amount released was about 0.01 percent in an immersion

uest after exposure to a corrosive SO2 environment for two years. Table 3.6

3-33
summarizes the results of the corrosive environment and other source integrity

tests.

Since incinerator residue is also disposed of in landfills, incinerated

ICSO's must also be assessed for source leakage. Results of 12000C temperature

tests on Am-241 sources indicate that post-test source wipes normally yield loose

contamination levels which are less than one percent of initial source

activlty( 3 4 ). Incinerated sources which are subjected to percolation in

landfills for long periods of time can be expected to release higher levels of

loose contamination. This assessment assumes that ten percent of ICSD's disposed

of in landfills have previously been incinerated and that these sources can lose

up to ten percent of their initial activity in a year. The remaining 90 percent

of ICSD's are assumed to lose up to 0.01 percent of their activity in a year.

Here, as in previous analyses, it is assumed that ten million units may be

disposed of in a year, and that the average source activity is 3 uCi of Am-241.

Once in the leachate, Am-241 will migrate at a rate dependent on the

physical and chemical composition of the soil and the chemical form of the

americium' Cline(35) has shown that the downward migration of Am-241(N0 3 ) 4 is

largely dependent on soil pH. His results indicated that, after leaching with

100 inches of irrigation water, 98 percent of the americium was retained in the

top one centimeter of acid (pH=4.5) soil, whereas only 76 percent remained in the

top layer of basic (pH=7.5) soil. Maximum americium penetration was observed to

be 20 centimeters in the basic soil and five centimeters in the acid soil. The

percolating water can experience one of four types of interactions as it moves

through the unsaturated zone above the aquifer. It can either (1) move virtually

unchanged, (2) experience' a net gain of solute or suspended matter, (3)*

experience a net loss of solute or suspended matter, or (4) maintain the same

total ionic concentration with net exchange of ions with the sorption medium.

Adsorption is strongly influenced by particle size of the sorption medium; the

more finely divided the solid, the greater the surface area per unit volume.

Thus, clays and silts have much greater adsorptive capacities than do sands or

gravels. HaJek( 36 ) has reported that the fraction of soil-bound americium which

can be readily moved by an invading solution is quite low. The ratio of solution

movement to americium movement is reported to be of the magnitude of 104

indicating a very slow leach rate.

3-34
Table 3.6. Results of Tests in Which Am-241 Foils Were

Subjected to Various Corrosive Conditions.18

Zw

Activity Activity Corrosive Wipe Test Immersion Total Activity

Sample Loading Atmosphere Lost

OCi pCi/2c nCi nCt %

Foil type 160 128 H2S thT.() n.T. N.T.

Ai-241 so2 1.0 17.0 0.01

I cm long strip NtHt 6.9 13.6 0.01

HCl 1.6 7.6 oO

Salt Spray 2.0 0.4

Foil Type 500 400e H2S 7.5 13.9 0

Pe-241 H S 26.8 33.7 0.01

I cm long strip SN 10.3 56.9 0.01

OH N.T. N.T. 0

8CI 0.5 38.5 0.01

Salt Spray 56.3 10.0 0.01

Platinum based 4 44 "2S 3.5 1.5 0.13

foil Am-241 . ,S 2.1 0.7 0.07

3 m x 3 mS02 0.7 0.1 0.02

square S02 0.6 0.1 0.02

t113 N.T. N.T. 0

HC1 1.0 2.4 0.09

HICI 1.5 2.4 0.10

Salt Spray 0.4 0.1 0.01

Sal Spray O.S 0.1 0.02

Gold based 442S 0.2 0.2 0.01

foil Am-241 1h2S 0.2 0.2 0.01

10 M x 10 m S02 0.3 0.1 0.01

square S 0.2 0.1 0.01

sHM3, H N.T. N.T. 0

Salt Spray N.T. N.T. 0

Notes: (1) H. T. a Not Tested (2) 0 - 'CO.005%
Another important parameter concerning the movement of contaminants in

ground water is the degree to which the contamination is dispersed both

longitudinally (in the direction of ground water flow) and transversely. The

dispersion coefficient of an aquifer is a measure of the actual dispersion as

determined by aquifer permeabilities and hydraulic gradients. The U. S.

Geological Survey has determined that, under a gradient of 2 m/km, the rate of

ground water flow can vary from 18 m/day in gravel to 0.3 m in 30,000 years for

clay 3. The transverse dispersivity, which may be described as the inherent

capability of the aquifer to cause dispersion in a transverse direction is

dependent primarily on the complexity (on a microscopic level) of the paths taken

by the fluid, and (on a macroscopic level) inhomogeneities within the

aquifer(29). Figure 3.6 depicts two examples of contamination plumes in aquifers

with different transverse dispersivities. Since contamination plumes are

observed to travel in a rather well-defined manner, it is evident that dilution

by the surrounding body of ground water is not a major factor.

From the above discussion, it is apparent that definite statements

cannot be made concerning the distance and direction that contamination will

travel due to the wide variability of aquifer types and contaminant

characteristics. This problem is further compounded by the scarcity of data

related to the behavior of americium in soil and plant systems. (See Reference

38 for a review of this subject.) There is reason to believe, however, that the

migration of americium in the zone of aeration is a very slow process in which

most of the americium will be adsorbed on soil particles( 3 6' 3 8 ). Once in the

zone of saturation, the contamination plume will travel in a well-defined state,

the degree of dispersion depending on aquifer conditions.

This assessment will assume the following:

1. Ten million ICSO's are disposed of in one year with an

average source activity of 3 uCi.

2. Ten percent of ICSD's disposed of in landfills have been

previously incinerated and these sources can lose up to ten

percent of their initial activity in one year.

3. The remaining 90 percent of ICSD's lose up to 0.01 percent of

source activity in one year.

4. One-half of the total activity leached from americium sources

in one year eventually enters the ground water during a

similar interval.

3-36
/ DISPOSAL--.--

DIRECTION OF

GROUND-WATER FLOW

... .....

IL....S......

IlI

I

a) CHLORIDE PLUME, INEL, IDAHO

Transverse dispersivity: 450 feet

Time: 16 years

DIRECTION OF

GROUND-WATER FL I

'I'

(1

t

I I

I I

ow( .1

I I

1 1

4-1000 ft, 2

.

:::...~i

\~ /

I

0

0

0

- t

b) CHROMIUM PLUME, LONG ISLAND

Transverse dispersivily : 14 feet

Time: 13 years

Figure 3.6. Examples of Transverse DOfpersion Patterns

of Contamination Plumes.B'e

3-37
5. The volume of

gallons, all

available for

leachate generated per year is 90 billion

of which enters the ground water system and is

withdrawal.

6. There is no significant dilution of the zone of contamination

from surrounding ground water.

7. One percent of the contaminated water is withdrawn for

domestic water supply and live percent of that amount is

consumed as drinking water .

The concentration (uCi/ml)of americium in

enters the zone of saturation would be

the leachate (A,) as it

A2 A J2 1f22/V2

where

At - Total activity in the landfill (uCi),

= Fraction of total activity leached,

-S Fraction of activity in the leachate is not

removed before entering the zone of saturation, and

Total volume of leachate produced over the time of

interest(ml).

Thus, under the assumed conditions, the average americium concentration in all of

the leachate generated in one year would be

(3x10 7 uci)(0.5)((0.1)(0.1) + (0.9)(0.0001))

(90xIO 9 gal)(3.8xlO3 ml/gal)

4.4x10"0 uCi/ml.

In light of Environmental Protection Agency recommendation that all ground water

withdrawal points should be located a "safe distance from sources of pollution"

or "where water resources are severely limited, ground water aquifers subject to

contamination may be used for water supply if adequate treatment is provided,"

this estimate of the fraction of contaminMI ground water which, reaches drinking

water supplies may be grossly exaggerated '

3-38
Since the concentration guide (10CFR20, App. B) for americium in water

is 4x10 6 uCi/ml for soluble forms and 3x10" 5 uCi/ml for in soluble forms (the

latter is probably the more relevant case here), the concentration of this

nuclide in the leachate is a very small fraction of the allowable limits: about

0.01 percent of the soluble limit and 0.001 percent of the insoluble limit.

The amount of activity ingested (A in) as a result of contaminated

water in the drinking water supply can be estimated by

A1 ng V2 fdlfd2Af

where

v - Volume of leachate generated in one year (ml),

fd, = Fraction of contaminated ground water which is

withdrawn for domestic water supply (0.01), and

fd2 = Fraction of domestic water supply which is consumed as

drinking water (0.05).

The dietary intake by the entire U. S. population, Aing, in this scenario would

be:

A = (9OxlO9gal)(3.8xlO3ml/gal)(0.01)(0.05)(4.4x10"10 Aing uCi/ml)

= 75 uCi.

The 50-year dose commitment (0 ng) to the exposed population from

ingestion of contaminated water is estimated by

Ding = (Aing) (DCFi)

where

DCF1 = Dose conversion factor for organ i (rem per uCi ingested).

Table 3.7 shows the results of this calculation utilizing the dose conversion

factors from the INREM computer code The dose commitment to the maximally

3-39
Table 3.7 . Fifty-year Dose Commitments Resulting from Intake

of Contaminated Ground Water and Food Crops.

I

0

Dose

Reference Intake

Case (NOC) Total Body Skeleton Liver Kidneys

Ground Water

Maximally Exposed 1.6E-4 8.7E-6 l.3E-4 4.6E-5 6.5E-5

Individual (rem)

Total Population 7.5E+l 4.1E+O 6.2E+1 2.1E+l 3.lE+l

(person-rem)

Food Crops

Average 1.OE-8 5.7E-10 8.2E-9 2.9E-9 4.1E-9

Individual (rem)

Total Population 2.3E+O 1.2E-1 1.9E+O 6.6E-1 9.4E-1

(person-rem)
exposed individual is assessed in the same manner, except that it is assumed that

the annual dietary intake of water (Iw) is 370 liters and consists entirely of

ground water contaminated with Am-241 at the same concentration as calculated for

leachate (i.e., 4.4x10"I0 uCi/ml):

A1 ng m lw A

(370 1)(4.4x 10-10 uCi/ml)(103 ml/l)

= 1.6 x 10-4 uCi.

The dose commitments arrived at in this manner are extremely low when compared to

total body doses received from natural background radiation over the same period

*of interest. For the entire ground water-dependent population (48 percent of the

total U. S. population), this figure would be approximately ten million

person-rem, or about two million times that received in the above assessment (4.1

person-rem). In the case of the maximally exposed individual, the total body

dose that person receives from a one-year ingestion of contaminated water

represents an amount equal to about 10- 4 the amount due to natural background.

Skeletal doses are also lower by several orders of magnitude.

Johnson(32) has assessed the impact of landfill disposal of ICSD's by

comparing the resultant Am-241 concentration in soil and water to that of

naturally-occuring Ra-226, a bone-seeking alpha emitter similar to Am-241. He

assumed that a steady state U.S. inventory of 156 Ci of Am-241 exists (one ICSD

per dwelling, 2.5 uCi per ICSD), and that all detectors are disposed of in

landfills after a mean life time of five years, and arrived at a concentration-of

Am-241 in landfill refuse of 0.11 pCi/g. This estimate does not assume any

dilution by soil and is therefore a "worst case" estimate of the concentration.

Despite this conservatism, the resultant soil concentration is several times

lower than the average concentration of naturally-occurring Ra-226 (about 0.6

pCi/g). Johnson goes on to assume equal solubilities and transfer from soil to

diet for radium and americium and arrives at a uworst case" dose rate to the

.skeleton of 0.002 mrem/yr.

Wrenn( 3 3 ) has applied the findings of Bennett( 4 1 ) to show that

americium in the environment is very poorly returned to man via diet. The

cumulative deposition of Am-241 on the surface of the U. S. as a result of

atmospheric weapons testing is now about 5000 Ci, and the current annual average

3-41
per capita dietary intake isabout 0.4 pCi. Thus, assuming no dramatic changes

in these figures over the next 70 years, the lifetime intake of an individual

would be about 28 pCi. For a population of 200 million people, this represents

an integrated lifetime intake of 5.6 mCi, or roughly 10-6 of the total americium

distributed. Using this value and assuming that ten percent of the AM-241 from

ten million detectors (Wrenn assumed 2 uCi each) leaches or otherwise becomes

available to move about in the environment, the collective intake would be

(107 detectors)(2 uCi/detector)(0.1)(10 6 ) = 2 uCi.

This figure corresponds to 50-year dose commitments to the entire

population of 0.11 person-rem for total body, 1.64 person-rem for bone, 0.52

person-rem for liver, and 0.81 person-rem for kidneys.

Contamination of food crops grown on reclaimed landfill sites or on

lands adjacent to landfills can result from irrigation with water withdrawn from

a contaminated ground water source. Radioactive material can be transferred to

the plant by either deposition (as in the case of sprinkler irrigation) or by

root uptake. The transfer coefficients describing the movement of americium in

the food chain vary widely depending on crop and soil type, climate, method of

irrigation, etc.

Although irrigation is used on only about 11 percent of U. S. cropland

acreage, irrigated areas contribute about 25 percent -,f the total crop production

value. About 85 percent of the irrigated acreage is in the 17 Western states,

and underground aquifers provide for about two-thirds of the irrigated acreage

nationwide( 4 2 ). The two principal methods of application consist of sprinkler

systems such as center pivot, side roll, and hand or mechanical move systems, and

surface systems such as ditch or grated pipe networks. Approximately.30 percent

of irrigated acreage receives water from sprinkler systems, while surface

application systems account for about 70 percent of the irrigation.

Radionuclides which are deposited on the exterior surfaces of crops by

sprinkler irrigation will be removed by weathering forces such as wind and rain,

and by mechanical forces such as subsequent irrigation. Literature values for

the fraction of radioactive fallout (Sr-90, Cs-137, etc.) which is intercepted

and deposited on crop surfaces range from 0.3 to 0.6 with a reduction of that

fraction by a factor of four after a thirty-day period( 4 3 -48 ). Assuming an

average deposition-to-harvest period of thirty days, this results-in a range of

3-42
0.075 to 0.15 for the fraction of the deposited activity remaining on the plant

surface at the time of harvest, For Am-241 uptake by root systems literature

values are on the order of 10-4(49,50).

There are many other factors which tend to reduce the fraction of

deposited activity eventually consumed. Among the more important of these

factors are the partitioning between plant surfaces and edible portions, losses

due to harvesting and food processing, and removal by kitchen activities such as

washing or cooking. The partitioning coefficient (i.e., the ratio of deposited

activity on the edible portion of the plant to activity on the exterior plant

surface) may be as high as unity for leafy green vegetables such as lettuce or

spinach, or as low as a small fraction of unity for.crops in which the edible

portion is protected by a non-edible layer (e.g., nuts, grains or citrus fruits).

Other factors such as the different uses to which crops may be put (animal feed,

seed production, food products and by-products, etc.) also tend to reduce the

fraction of deposited activity which is ultimately consumed by humans.

The assessment of human consumption of contaminated food crops grown on

or near landfill sites assumes the following:

1. Ten percent of the 500,000 acres currently used for landfill

disposal is reclaimed for the purpose of raising food crops,

and an equal amount of land used for raising food crops is

located close enough to landfill sites that irrigation with

contaminated ground water is likely.

2. 25 percent of the crop acreage is irrigated, and sprinkler -

type systems account for 30 percent of this irrigation.

3. The crop acreage receives an average of 36 inches of

irrigation water per.year. Ground water provides the source

for 70 percent of this irrigation, and ten percent of the

ground wateri•s contaminated with Am-241 at a concentration

of 4.4 x 10- uCi/ml.

4. Half of the Am-241 in sprinkler irrigation water is deposited

on plant surfaces, and ten percent of this deposition occurrs

on edible portions .of the plant.

5. 25 percent of the activity deposited remains on plant

surfaces at time of harvest, and 25 percent of this residual

activity remains on edible portions after harvesting,

processing, etc.

6. The plant uptake factor for Imertcium deposited on the soil

surface by irrigation is 10-", and ten percent of this uptake

is deposited in edible portions.

3-43
7. The amount of deposition on plant surfaces I

drip irrigation is negligible, as is

americium in the sub-surface soil system.

8. Eighty percent of the edible portions of the

is consumed.

The total amount of activity ingested from consumption

(Ic) is estimated by:

From surface

flant uptake

or

of

harvested crop

of contaminated food crops

=c AwVw(fd + fs) fc

where

Vw

Concentration of Am-241 in contaminated ground water (uCi/ml),

= Volume of contaminated ground water used for irrigation (ml),

Fraction of activity in sprinkler irrigation water which is

deposited and retained on edible portions until consumption,

Fraction of activity deposited on soil which is taken up by

edible portions of the plants, and

fs

fc = Fraction of harvested crops which are consumed.

Using the above assumptions, the activity ingested is

Ic - (4.4x10- 10 uCi/ml)(6.3x1O1 2 ml)(lxlO" 3 + 1x10" 5 )(0.8)

2.3 uCi.

This figure represents a 50-year dose cormnitment to the exposed

population of 0.12 person-rem for total body, 1.89 person-rem for bone, 0.66

person-rem for liver, and 0.94 person-rem for the kidneys. If it is assumed that

the exposed population in this scenario is the entire U. S. population, the

3-44
average individual intake would be about 0.01 pCi, which is a factor of forty or

so less than the Am-241 dietary intake from weapons testing fallout. Average

individual organ dose commitments would be 5.7 x 10-10 rem for total body, 8.2 x

10-9 rem for bone, 2.9 x 10-9 rem for liver and 4.1 x 10-9 rem for kidneys.

3.2.6.1.3.2 Resuspension

Loose Am-241 contamination may become an inhalation hazard if left

uncovered at landfill disposal sites. Airborne contamination can result from

suspension of particulate matter by open burning, weather, or other factors.

Johnson(32) has estimated the degree of resuspension which can be expected by

comparing the landfill concentrations of americium (assumed to be uniformly

distributed and undiluted by added fill) with soil concentrations of natural

uranium. Mean soil concentrations of uranium average 0.93 pCi/g and

concentrations in air range from 3.3xlO'6.pci/m3 to 5x10" 4 pCi/m 3 . Using the

more conservative figure for air concentration, and applying this ratio to the

0.11 pCi/g value previously determined for Am-241 landfill concentration, the

resulting Am-241 concentration in air around landfill sites would be 5.9x10"5

pCi/m3. A person residing in the vicinity of the landfill and breathing 20

m3 /day air at this concentration would have an annual Am-241 intake of 0.43 pCi.

Wrenn(33) has used this same approach to arrive at an estimate of the

resuspension of buried incinerator residue. He calculates an air concentration

of 4x10 6 pCi/m 3 , the inhalation of which would result in an annual individual

intake of 0.3 pCi.

Since open burning is a common problem contributing to the dispersal of

contaminants at landfill sites (see Table 3.5), an assessment of the hazard posed

by suspension of loose contamination by this mode is performed below.

Mishima and Schwendiman( 5 1 ) have determined that the burning of

combustible solid wastes contaminated with uranium (to simulate plutonium)

resulted in low fractional releases Measured-airborne concentrations in the test

chamber indicated the presence of from 0.003 to 0.05 percent of the uranium used

in the source. Since the uranium forms used were conducive to easy removal

(e.g., powders or residues from drying solutions), these values probably

represent worst case estimates when related to americium sources, even those in

incinerator residue. Using the 0.05 percent value, and assuming that one-half of

3-45
the ten million detectors disposed of in the reference case are subjected to open

burning in landfills, the total amount of americium released would be

(107 detectors)(3 uCi/detector)(0.5)(0.0005) = 7500 uCi.

Assuming that the number of disposal sites with open burning is ten

thousand, the amount of released activity per site would be about 0.75 uCi. Most

of this activity will probably be associated with particles less than ten microns

mass median aerodynamic diameter.

The amount which is returned to people via diet can be estimated using

the previously stated fraction of 10-6 of the total environmental americium. The

lifetime intake for a population of 220 million people which would result from

the release of 7500 uCi would therefore be 7.5 x 10-3 uCi, or about 3.4 x 10-5

pCi per person.

The amount of resuspended americium that is inhaled can be estimated

from the data reported by Bennett regarding plutonium fallout( 5 2 ). About 16,000

Ci of Pu-239 have been deposited on the U. S. as a result of atmospheric weapons

testing. The cumulative inhalation intake from 1954 to 1972 was about 42 pCi per

person. Thus, assuming that americium availability is similar to plutonium, the

total per capita inhalation by the U. S. population would be 1.5 x 10-4 pCi/yr

per Ci available. The average individual inhalation rate resulting from the

resuspension of 7500 uCi would be 1.1 x 10-6 pCi/yr. This represents a

population inhalation rate of 250 pCi/yr. The doses resulting from these

exposures are presented in Table 3.8.

3.2.6.1.4 Incineration

Approximately 13 million metric tons of municipal solid waste are

incinerated annually in this country. Most of this incineration occurs in the

300 or so large municipal incinerators currently operating. A significant amount

also occurs in thousands of intermediate or apartment complex incinerators which

are prevalent in many large urban areas such as New York and Philadelphia. The

relative importance of conventional incineration as a means of waste processing

in the near future is questionable at this time. Stricter air quality standards

3-46
Table 3.8. Fifty-year Total Body and Organ Dose Commitments Resulting

From Resuspension of Am-241 in Landfills.

!

4•

Dose

Reference

Case Intake (pCi) Total Body Kidneys Liver Bone Lungs

Inhalationa

Individual .E-12 1.OE-8 2.OE-10 3.3E-10 3.6E-10 5.6E-10

(rem)

Population 2.5E-4 6.2E-3 4.4E-2 7.8E-2 8.2E-2 .3E-l

(person-rein)

Ingestion

Individual 3.4E-11 1.8E-12 1.4E-11 8.9E-12 2.9E-11

(rem)

Population 7.5E-3 4.ME-4 3.2E-3 2.OE-3 6.2E-3

(person-rem)

a. Inhalation dose assumes particle size of 1 micron and solubility class Y.
and increased capital and operating costs are combining to drive up the overall

cost to prohibitive levels. One review recently reported that, despite the

increased sophistication of present-day incinerators in the U. S., none is

apparently operating in a wholly satisfactory manner

The primary function of an incinerator is to reduce the municipal waste

volume to a compact, sterile residue. Some incinerators also have secondary

functions such as the generation of steam or some other utilization of waste

heat. Non-conventional incineration methods such as pyrolysis result in the

production of a storable, transportable fuel from municipal solid waste. These

methods, however, are still in early developmental stages in this country.

In conventional incinerators, refuse is either pretreated for size

reduction (e.g., shredding or grinding) or fed directly into the combustion

chamber via some continuous-feed or batch-feed process. The refuse is oxidized

in the combustion chamber in which the temperature is usually regulated by using

excess air (i.e., air that is in excess of the amount theoretically required to

completely burn the combustible portion of the refuse). Typical furnace gas

temperatures are controlled to around 1000-11000C, although the actual

temperature of the flame is approximately 13000C. These conditions will usually

result in reducing the bulk by oxidation to 20-25 percent of the original weight

and 10-12 percent of the original volume 27 . The residue which remains consists

mostly of metals, glass, ceramics, stones, ash and unburned combustibles. if

temperatures in the furnace are maintained at about 16500C or more, the residue

will be reduced to a molten state called slag. Incinerator residue is

essentially sterile and compacts well. Thus, if used for landfill, the land can

be immnediately reclaimed. Alternatively, the metallics in the residue can be

separated out for salvage and the residual ash can be used as a valuable

substitute for sand and aggregate in building-or road construction (

27 ) ' Most large incinerators require water in various. parts of the

incineration process (e.g., gas scrubbing and residue quenching). The water

usually becomes contaminated with dissolved or suspended matter and in most cases

requires treatment before discharge to prevent or control pollution of surface or

ground water systems. The most serious environmental problem associated with

incinerators, however, is pollution of the air.

When refuse is burned, large quantities of fine ash particles, water

vapor, carbon dioxide and other *gases are released. Recently constructed

incinerators control the amount of particulate emission by such measures as high

3-48
efficiency combustion and particulate collection systems such as electrostatic

precipitators and gas scrubbers. Table 3.9 shows the particle size distribution

obtained from measurements of stack gases in a large municipal incinerator.

Particle size and other physical properties of the particulate emissions such as

density, depend on many factors such as refuse composition, incinerator design and

operation and air pollution control systems. The particle size distribution in

Table 3.9, for example, is typical of stack gases that have passed through a

cleanup system consisting of a combustion settling chamber and a wet baffle

3

system. The density of these particles is about 1.85 g/cm

The concentration of particulates in stack gases and the total amount

of particulate releases for several different types of large incinerators are

given in Table 3.10. The particle concentration or "dust loading" is expressed

in limits of grains (7,000 grains equals one pound) per standard cubic foot of

gas normalized to 12 percent CO2.

Various processing systems have been used to remove particulates and

other pollutants from incinerator effluents. Older incinerators used such

methods as settling chambers, wet baffle systems or cyclone collectors.

Collection efficiencies for these systems vary from around 35 to 75 percent, an

insufficient amount of removal for compliance with current emission standards.

Efficiencies of 90 to 99 percent are available in currently used systems such as

gas scrubbers and electrostatic precipitators. Some average removal efficiencies

for various types of air pollution control systems are given in Table 3.11. It

is noteworthy that about 70 to 75 percent of the incinerators in the United

States were built before 1960 with many dating back to the 1940's and

beyond( 26 ' 5 6 ). These incinerators require air pollution control retrofitting in

order to comply with current regulations.

Prediction of the amount of airborne radioactivity released as a result

of incineration of ICSO's with municipal refuse depends on knowledge of ICSD

source behavior under conditions of thermal stress. Results of high temperature

(1200 0C) tests performed on Am-241 ICSO sources indicate that between 0.01 and

0.2 percent of the source activity (with an average value of 0.05 percent) may be

released as airborne contamination. Tests involvIng whole smoke detectors at the

same temperature resulted in the release of less than 0.06 percent of source

activity( 34 . It can be expected, therefore, that incineration of ICSD's should

not result in the release of more than about 0.1 percent of source activity.

3-49
Table 3.9. Size Distribution of Particles in Incinerator Stack Gas. 2 7

Slze(vm) % by Weight

>30 31.3

>20 52.8

>10 79.5

>5 94.0

<5 6.0

3-50
Table 3.10. Particulate Emission for Incinerators

of Various Designs. 5 4

3-51
Table 3.11. Average Air Pollution Control System Removal Efficiencies (Weight Percent). 55

Mineral Combustible Polynuclear Volatile

Air Pollution Control System Particulates Particulate Hydrocarbons Metals

None (flue settling only) 20 2 10 2

Dry Expansion Chamber 20 2 10 0

Wet Bottom Expansion Chamber 33 4 22 4

Spray Chamber 40 5 40 5

N Wetted Wall Chamber 35 7 40 7

Wetted, Closed-Spaced Baffles 50 10 85 10

Mechanical Cyclone (dry) 70 30 35 0

Medium-Energy Wet Scrubber 90 80 95 80

Electrostatic Precipitator 99.9 99 67 99

Fabric Filter 99.9 99.9 97 99

& 4 A
Three reference cases are assessed here concerning the environmental

health impact of Incineration of discarded ICSD's:

1. The calculated dose to an individual at the point of maximum

exposure to the emission plume from a large municipal

incinerator.

2. The calculated dose to the population feeding one incinerator

disposal route.

3. The calculated dose to the total U. S. population residing

in the environs of large municipal incinerators.

The assumptions used to estimate the amount of Am-241 in incinerator

emissions and resultant exposures are as follows:

1. There are a total of 300 municipal incinerators, each

processing 300 tons of refuse per day at 50 percent excess

air.

2. The number of ICSD's incinerated per year is one million

(i.e., ten percent of the ten million which may be disposed

of in peak years).

3. The average Am-241 activity per detector is 3 uCi.

4. The fraction of Am-241 released during incineration is 0.1

percent.

5. The efficiency of Installed air pollution contol systems for

particulates is 90 percent.

6. The aerodynamitc mean activity diameter (AMAD) of the released

particles is one micron.

7. The number of persons feeding one incinerator disposal route

(assumed to be the exposed population) is

(220x10o)(0.1)/(300) = 73,000 persons.

The total activity released in a year (Q) would be

Q = Qifsfr

3-53
where

Q = Initial Am-241 source activity (uCO),

fs = Fraction of Am-241 released during incineration, and

fr = Fraction of released activity which escapes with stack gases.

Based on the assumptions listed above,

Q = (3 x 106 uCi)(O.OO1)(0.1)

= 300 uCi

or about 1 uCi per incinerator.

The concentration of americium in the stack gas (Xs) would be

XS=

VaWr

where

Va 50 percent excess of the theoretical volume of air required for complete combustion of one pound of refuse (cm /lb),

Wr Weight of refuse incinerated (ib).

The average annual stack gas concentration that would result from the

scenario above would be

X £ (1 uCi)/((2.0xl06 cm3 /lb)(2.2xlO8 lb))

= 2.3x10"15 uCi/cm3 .

The concentration of americium in the stack gas would be about two orders of

magnitude below the most restrictive standard for Am-241 concentrations in air.

Using the atmospheric dispersion data-of Martin( 57 ) and assuming a constant wind

speed of 1 m/s under moderately stable meteorological conditions, the maximum

downwind concentration (X) can be estimated by

3-54
X M Q'(X/Q)

where

Q = Release rate in (uCi/sec), with release constant over one year,

X/Q Atmospheric dispersion coefficient (sec/n 3 ).

Thus, for this case, the maximum downwind Am-241 concentration would be

(3.2 x 10- uCi/s)(2 x 10-5 s/m3 ) = 6.4 x 10-13 uCi/m 3 .

Assuming an average daily breathing rate of 20 m3 per day, the maximum

exposed individual would inhale about 4.7x10°9 uCi per year. If it is

conservatively assumed that the average person in the exposed population takes in

an amount of Am-241 equal to one-third of that at the point of maximum

concentration, the average incinerator population intake would be 1.2x10" 4 uCi.

Summing this over the entire exposed population (i.e., about 20 million persons),

the total intake would be about 3.5 x 10-2 uCi. The doses resulting from the

above exposures were calculated using the DACRIN( 5 8 ) computer code, and are

presented in Table 3.12.

The intake of dispersed Am-241 via the ingestion pathway is assessed on

the basis of the dietary intake factors discussed previously. Since it has been

estimated that 106 of the total environmental americium will eventually be

returned to man via dietary intake, the total amount of Am-241 ingested by the

exposed population would be about 3.0 x10 4 uCi, or about 1.3 x 10-11 uCi per

individual. Dose commitments associated with these intakes are listed in Table

3.12.

3.2.6.2 Abandonment in Buildings

As long as ICSD sources remain intact, the external radiation

represents the most significant mode of exposure. The abandonment of ICSO's in

buildings, therefore, is unlikely to constitute a unique hazard situation since

the conditions of exposure are not unlike normal residential exposures. The main

3-55
Table 3.12. Summary of 50-year Total Body and Organ Dose Commitments

Associated with Incineration of One Million ICSD's Containing

3 uCi of Am-241.

Dose

Reference Io.Knsg Case Intake (NCi) Total Body Kidneys Liver I Bone Lungs

Ch

Inhalationa

Maximally Exposed

Individual (rem)

Population Around

Incinerator

(person-rem)

Total Exposed

Population

(person-rein)

Ingestion

Avg. Individual

(rein)

Population Around

Incinerator

(person-rem)

Total Exposed

Population

(person-rem)

4. 7E-9

1. 2E-4

3.5E-2

1.3E-11

1 .OE-6

3.OE-4

1.lE-7

2.9E-3

8.2E-1

7.2E-13

5.4E-8

I .6E-5

8.7E-7

2.2E-2

6.1 E+O

5.4E-12

4.1E-7

1.2E-4

1.5E-6

3.7E-2

1. lE+l

3.8E-12

2.9E.7

8.6E-5

1.6E-6

3.9E-2

1. 1E+lI

1.1E-11

8.2E-7

2..5E-4

2.6E-6

6.1E-2

1.7E+1

I A .a 1 J

a. Assumes particle size of 1 micron and solubility class Y.
difference, of course, is the fact that there will be fewer person-hours of

exposure in the case of the abandoned buildings.

Demolition of buildings containing ICSO's is another situation which

should be considered. Tests have shown that a high degree of source integrity is

maintained under conditions of chemical or physical stress( 18 , 3 4 ). For example,

impact tests (sources dropped -from a height of nine meters onto a flat, rigid

surface) and percussion tests (a 1.4 kg steel billet is dropped from a height of

one meter onto the sample placed on a sheet of lead supported by a smooth solid

surface) have shown that less than 5x10"7 and 5x10"6 uCi, respectively, were

removed in post-test wipe and immersion tests. Abrasion tests in which sources

were subjected to impact from a stream of sand particles (SiC grade 120) falling

from a height of one meter through a one cm bore glass tube also showed that a

high degree of integrity is maintained under severe conditions. After about 8.3

hours of abrasion, 5x103 uCi (0.001 percent of source activity) was removed by

wipe tests. The test fO-l did not start leaking badly until after about 14 hours

of abrasion at which point the active layer was exposed. It is evident, then,

that the severe physical forces to which ICSD's may be exposed in the course of

building demolition will probably not result in a significant release of

radioactivity. Internal doses to personnel involved in the demolition or rubble

removal operations will in all likelihood be minimal.

The situation becomes

been subjected to a substantial

extent the integrity of ICSD

thermal and mechanical stresses

follows, then, that severely

inhalation hazards and should bi

demolition operations such as

of the crew regarding potential

internal contamination. This a

more complex if the building being demolished has

amount of fire damage. It is not clear to what

sources would be maintained after a combination of

such as would be expected in these instances. It

burned ICSD's should be considered as potential

e handled with caution. It is evident that in

those involving fire-damaged ICSD's, an awareness

inhalation hazards would minimize the risk of

SIpect is discussed further in Section 3.2.7.2.

3.2.7 Accidents or Misusage

During the use of any consumer product, it is anticipated that

accidents or misuse of the product will occur. This is true of ionization

chamber smoke detectors. Past experience has shown that accidents do occur. For

ICSD's with Am-241 the following accidents are postulated to occur:

3-57
1. Ingestion of foil source.

2. Storage fire.

3. Residential fire.

The list is not all inclusive but does represent a variety of accidents

or abnormal occurrences. For all cases the doses and dose commitments are

calculated in a conservative fashion.

3.2.7.1 Ingestion of Sources

During the manufacturing process of ICSD's, workers can come into

direct contact with the small Am-241 foils used in the detectors. It is

anticipated that during operations dealing with the foil sources, a foil or two

may be misplaced. A case of two foils being accidentally swallowed by a woman

working with the sources has been documented( 59 ). For this study, the swallowing

of sources is considered to be the accident of most concern on the assembly of

ICSD' s.

The documented case involved a woman swallowing two sources of Am-241

each containing a nominal 2.5 uCi of activity. The two sources were passed by

the woman after 16 and 24 days respectively. Analysis showed a little less than

one percent of the total activity of the two sources was found in the fecal

material after removal of the sources. Am-241 was detected in the urine until

the second source had been passed. The systemic burden was estimated to have

been "very much less" that 1.5 percent of the activity released from the sources.

The authors of the journal article concluded "this was not significant from the

point of view of radiological protection." They also stated "if the sources of

Am-241 involved in this incident are representative of those incorporated in

domestic smoke detectors, then the most important conclusion that can be drawn is

that they are remarkably secure. Furthermore, what activity is released under

these circumstances in so inert that there is negligible (much less than 1.5

percent) absorption into the blood. This is an important and comforting finding

in view of the growing numbers of. smoke detectors available to the general

public."

To calculate the dose commitment the woman will receive from the

incident, it is assumed, conservatively, that one percent of the activity was

released from the sources and ingested by the woman. Using the dose commitment

3-58
conversion factors for ingestion given in Appendix B, the 50-year dose

comuitments to organs of importance are given in Table 3.13.

3.2.7.2 Fires

3.2.7.2.1 Warehouse Fires

The primary radiological concern regarding fires in warehouses where

large numbers of ICSD's are stored is the inhalation of released Am-241. The

50-year dose commitment to firefighters involved in the extinguishment, cleanup,

and salvage operations is assessed according to the following assumptions:

1. The maximum number of ICSO's to be stored in any distribution warehouse

is 1,000 units, each containing 3 uCi Am-241.

2. The volume of air in the warehouse is 3 x 103m

3. The breathing rate of persons involved is 1.2m3/hr.

4. 0.1 percent of Am-241 activity is released as airborne particulates

having a mean diameter of one micron.

Since it is unreasonable to assume that firefighters. would enter a

burning building without first ventilating it, there will be a number of air

changes resulting in a significant reduction in Am-241 concentration in building

air. Also, fires of the magnitude required to release this fraction of americium

will also release large amounts of other noxious materials. It is unlikely,

therefore, that firefighters would enter the involved building without

respiratory protection. It is also unreasonable to assume that the building will

not be well ventilated during the salvage and cleanup operations. This

assessment assumes that the net effect of the above and other factors is a

hundred-fold reduction in Am-241 inhalation.

The average concentration of Am-241 in building air would be

(3x10 3 uCi)(0.001)/(3xlO3 m3)=lxlO" 3 uCilm3 .

3-59
Table 3.13. Calculated Fifty-year Dose Commitments (Rem)

Resulting from Am-241 ICSD Source Ingestion.a

Total Body Bone Liver Kidneys

2.7E-3 4.lE-2 1.5E-2 2.1E-2

a. Based on the assumption that 1.0% (0.05 pCi) of the

swallowed source activity (5pCi) was ingested.

3-60
The total intake over an eight hour period would be

(Ix10" 3 uCil/m3 )(9.6 m3 )(0.01) = 9.6x10-5 uCi.

This intake, which should be considered an upper level estimate, would result in

the organ doses in Table 3.14.

Inventories of detectors at a manufacturer's warehouse can be

substantially larger than those at distribution warehouses. At such warehouses,

however, firefighters are probably much more likely to be aware of potential

hazards involved. It is common practice among most fire departments to

familiarize themselves with any industrial or warehouse materials within their

area of response which constitute significant exposure hazards. It is also

likely that posted warnings or verbal communications from plant personnel will

increase the probability of the firefighters being made aware of the presence of

radioactive materials. These factors, together with the conservatism included in

the distribution warehouse scenario, make it highly unlikely that substantially

greater exposures would result. Nevertheless, an assessment is made here for a

fire involving 105 detectors (3x10 5 uCi) in a warehouse of 3.5x104 m3 . Results

of this assessment are presented in Table 3.14.

The salvage and cleanup operations following a large warehouse fire can

be a source of significant internal depositi6-1 if performed in a careless or

unsuspecting manner. Wipe tests performed in the interior and exterior of ICSD

source mounting areas after high temperature (1200 0C) testing of the detectors

resulted in the removal of up to 0.2 percent of the source activity, although

only aboat 0.015 percent of the activity was on the accessible areas outside of

the source housing( 1 8 ). Suspension of up to 0.001 uCi per detector could

conceivably result from mechanical disturbance of the charred debris. The amount

of resuspended material that is inhaled and deposited internally depends on many

factors such as the volume of air in which the americium is suspended and the

size of the suspended particles. Assuming that one percent of the resuspended

material is inhaled, and that this activity consists mostly of particles of

respirable size (about one micron), the dose commitments listed in Table 3.14

would result. It should once again be emphasized, however, that it is likely

that salvage or cleanup operations after fires involving large numbers of ICSD's

3-61
Table 3.14. Fifty-year Dose Commitments for Individuals

Involved in Firefighting or Cleanup Operations.

Dose (rem)

Intake Total

Activity a (NCi) Body Liver Bone Lung

Firefighting

Distribution 9.6E-5 2.3E-3 3.2E-2 3.2E-2 5.OE-2

Warehouse

Manufacturers 8.2E-4 2.OE-2 2.6E-1 2.7E-1 4.3E-1

Warehouse

Residence 1.4E-7 3.5E-6 4.8E-5 4.8E-5 7.8E-5

Salvage and b

Cleanup l.OE-5 2.4E-4 3.2E-3 3.3E-3 5.2E-3

a. See text for assumed conditions

b. Intake per detector involved.

3-62
would be conducted with some awareness of the potential hazards and with some

measure of protection.

3.2.7.2.2 Residential Fires

This assessment deals with possible internal exposures to residents or

firefighters as a result of firefighting, salvage and cleanup operations. The

50-year dose commitment to persons involved is estimated based on the following

assumptions:

1. Two residential ICSD's are involved, each with 3 uCi Am-241.

2. The volume of house air is 500m3 .

3. The breathing rate of persons involved is 1.2m3 /hr and the operation

lasts for one hour.

4. 0.1 percent of Am-241 activity is released as airborne particulates

having a mean diameter of one micron.

As in the case with warehouse fires, credit must be taken for the

degree of protection afforded the involved persons by ventilation or the use of

respiratory protection. This assessment assumes that the net effect of these and

other protective features will be hundred-fold reduction in the amount of Am-241

inhaled. The total Am-241 intake over one hour would be

(6 uCi)(0.001)(1.2 m3 )(0.01)/(500 m3) = 1.4 x 10" 7 uCi.

0ose commitments associated with the amount of Inhaled activity are given in

Table 3.14.

As mentioned previously, salvage and cleanup operations can constitute

a potential inhalation hazard if conducted in a careless or unsuspecting manner.

Disturbance of charred debris can result in the suspension of up to 0.001 uCi of

Am-241 per detector involved.

3-63
3.2.8 Summnary of Radiological Health Impact

A summnary of the doses determined for the reference cases analyzed

above, and an estimation of the total number of resultant somatic and genetic

health effects are presented in this section. Tables 3.15 through 3.18 summnarize

the dose assessments, and Table 3.19 lists the number of health effects which are

estimated to result from these doses.

It is worth repeating here that one should not place a great deal of

confidence in the estimated doses due to the number of assumptions and

generalities which had to be made in the dose estimation process. These

estimates, however, should be considered of value in delineating the upper bound

of the total dose delivered to the population as a result of the manufacture, use

and disposal of the number ofAm-241 ICSD's distributed in peak sales years. The

largest total body dose contribution (about 100 person-rem) results from external

exposure of the population to the ganmma radiation emitted by the ICSD source,

while the greatest amount of internal exposure probably results from the

inhalation of airborne contamination released during incineration of discarded

ICSO's and from the ingestion of drinking water from contaminated aquifers.

Internal doses received from ingestion of contaminated food crops are estimated

to be less than those resulting from the incineration inhalation and drinking

water pathways.

The total number of fatal cancers which would be expected to result

from the population dose arrived at in this study 4s 0.03, and the total number

of genetic effects is 0.02. Thus, even though the calculated doses represent

upper level estimates, a single cancer death or serious genetic effect is not

expected to result from a yearly exposure of the occupational work force and the

general population to ionizing radiation from activities associated with Am-241

ICSD use.

The total number of health effects which could result from accidental

exposures (such as may be incurred from fires or demolition of buildings) is not

estimated here since the degree of uncertainty involved is large. However, since

the number of individuals involved in such instances represent a small fraction

of the population, and since the individual doses resulting from these exposures

are small, the radiological health impact from accidental exposure situations is

expected to be less than that from normal production and use.

3-64
Table 3.15. External Doses Associated with Manufacture

and Distribution of Am-241 ICSD's.

Dose

Activity Individual Population

_(rem) (Derson-rem)

Manufacturea l.OE+O 4.8E+1

Transportation 2.5E-3

Distributionb 5.OE-4 2.OE+l

Retail Sales

Consumers 4.2E-6 2.8E+l

Retail Clerks 5.OE-4 7.OE+O

Total 1.OE+2

"a.

b.

Includes Warehousing and Storage at Manufacturers

Includes Storage at Distribution Warehouses

3-65
Table 3.16. Annual External Doses Associated with

Normal Use and Disposal of Am-241 ICSD's.

Dose

Activity Individual Population

Activity _(rem) (person-rem)

Transport 2.2E-8 l.5E-l

Installation 4.5E-8 6.3E-l

Maintenancea 1.8E-7 1.3E+O

Operation 9.3E-6 9.7E+1

Waste Collection 4.0E-7 7.OE-2

Total 9.9E+1

a. Includes testing, cleaning, changing batteries, etc.

3-66
Table 3.17. Summary of 50-year Total Body and Organ Dose

Commitments Associated with An-241 ICSD Disposal.

w

Dose

Total Body Liver Bone Lungs

Reference a

Case II II 11

Inhalation

Incineration lE-7 8.2E-1 1.5E-6 1.1E+1 1.6E-6 1.1E+l 2.6E-6 l.7E+l

Resuspension l.OE-8 6.2E-3 3.3E-10 7.8E-2 3.6E-10 8.2E-2 .5.6E-10 1.3E-1

Ingestion

Incineration 7.2E-13 1.6E-5 3.8E-12 8.6E-5 1.1E-11 2.5E-4 - -

Contaminated 8.7E-6 4.lE+O 4.6E-5 2.lE+l 1.3E-4 6.2E+l - -

Groundwater

Irrigation 5.7E-10 1.2E-1 2.9E-9 6.6E-1 8.2E-9 1.9E+O - -

Resuspension 1.8E-12 4.1E-4 8.9E-12 2.OE-3 2.9E-11 6.2E-3 - -

a. Column I represents either maximum or average individual dose (see text for details)(rem).

b. Column II represents total population dose (person-rem).
Table 3.18. Summary of Total Body and Organ Doses(person-rem)

Associated with Annual Manufacture, Distribution,

Use and Disposal of Am-241 ICSD's.

Internal External

Organ Source Source Total

Liver 3.3E+I 8.8E+14 1.2E+2

Bone 7.5E+1 1.1E+2b 1.9E+2

Lung 1.7E+l 1.lE+2b 1.3E+2

Gonads 2.5E+1 9.9E+1c 1.2E+2d

Total Body 5.OE+O 2.OE+2 2.1E+2

a. Derived by multiplying external exposure (2.2E+2 R) by 0.4

(see Appendix B)

b. Derived by multiplying external exposure by 0.5

c. Derived by multiplying external exposure by 0.45

d. Total gonadal dose to the population. The genetically

significant dose (GSD) would be somewhat less

3-68
iable 3.19. Summary of Total Health Effects Expected

from Annual Manufacture, Use and Disposal

of Am-241 ICSD's.

T Dose Total Cancer Mortality

Tumors (person-rem) Or Genetic Defects

Liver 1.2E+2 1.8E-3

Bone 1.9E+2 9.5E-4

Lung 1.3E+2 3.3E-3

Total Body 2.1E+2 2.1E-2

Total 2.7E-2

Genetic Defects 1.2E+2 2.4E-2

3-69
The cancer mortality risk resulting from all life span activities

(including manufacture, ten years of use, and disposal) associated with 14

million ICSO's is presented in Table 3.20. It is conservatively estimated that

less than one fatal cancer is expected to result from exposures associated with

the number of ICSO's sold in a peak sales year. For comparison, the spontaneous

cancer mortality rate in the United States is about 1700 mortalities per year per

million people. (See Appendix C). For a total population of 220 million people,

the corresponding number of cancer mortalities per year in the United States is

about 370 thousand. The benefits derived from the use of Am-241 detectors, in

terms of life and property savings, are discussed in Section S.

The regulations and guidelines concerning smoke detectors containing

Am-241 are discussed in Section 2.3. An applicant for a license is required to

demonstrate their product is designed and will be manufactured such that certain

criteria are met. The criteria deal with dose and dose commitments during normal

use, effectiveness of safety features, and dose and dose commitements from low

and negligible probability events. Based upon the dose assessments performed in

this section, a comparison to the safety criteria follows.

First, wear and abuse of the Am-241 ICSD's during normal handling and

use was found not to result in a significant reduction in the effectiveness of

safety features. Two reasons are responsible for this conclusion: (1) the

external radiation levels are very low and (2) the containment of the Am-241 in

foils is very effective.

In regards to normal usage, excluding manufacturing, all calculated

doses and dose commitments were found to be less than Column I in Table 2.2. For

accident or abnormal situations all calculated doses and dose commitments were

found to be less than both Columns II and II. From this standpoint, it is

apparent that Am-241 ICSO's, as manufactured, easily are within the criteria set

forth in 10CFR32.27.

3.3 NON RADIOLOGICAL IMPACTS

The single major bulk component of both ICSO and photoelectric smoke

detectors is the plastic housing that surrounds the unit. This material is a

thermoplastic phenylene-oxide based resin which has a functional temperature

3-70
Table 3.20. Summary of Doses and Health Effects from

Manufacture, 10 Years of Normal Use and

Disposal of 14 Million Am-241 ICSD's.

Dose (person-rem) Estimated

Cancer

Organ Internal External Total Mortality . _Source Source

Liver 3.3E+l 4.8E+2 5.1E+2 7.7E-3

Bone 7.5E+l 6.OE+2 6.8E+2 3.4E-3

Lung 1.7E+1 6.OE+2 6.2E+2 1.6E-2

Total Body 5.OE+O 1.1E+3 1.1E+3 1.1E-1

1.4E-1

3-71
range of, 40°F to above 3000 F. For planning situations this material has the

important characteristic of being self-extinguishing. The material is highly

resistant to aqueous chemical environments and has excellent impact strength( 6 0).

Should this plastic material undergo pyrolytic decomposition or flaming

combustion, a considerable variety of chemical compounds could be produced. The

production and kind of chemicals produced depends upon the amount of heat and

oxygen present during the heating or burning process. The plastic itself

contains no nitrogens or halogens which in turn greatly reduces any possibility

of producing hydrogen cyanide or hydrochloric acid( 6 1 ). As to the actual

products produced during thermal degradation of the plastic no document has been

located that is specific to the major type used in smoke detector housings. No

single substance exists that is completely free of toxic effects to humans under

specific conditions. In a publication on toxicity of plastic combustion products

a hazard ranking was developed for several different polymeric materials and

Douglas Fir (62) The hazard ranking, reading from highest to lowest was

polytetrafloroethylene > polyvinyl chloride > Douglas Fir and flexible

polyurethane foam > fiber glass reinforced polyester > copper coated wire with

mineral insulation. Although the exact chemical compositions of the plastic

housing material is unknown the main thermal decomposition products would be

carbon dioxide and water(61). Carbon monoxide can be expected to be evolved from

the burning plastic but the quantity would depend upon the available oxygen.

These thermal decomposition products place the plastic material slightly above

wood in the human toxicity scale. The fact that the plastic is self

extinguishing makes it unlikely to be a toxic problem under conditions of

potential human survivability. That the plastic would not be undergoing thermal

decompostion under these conditions is somewhat confirmed by information from the

California Fire Marshall's Office( 6 3 . In what few instances that have been

noted by that office, the plastic was damaged by heat, the housing had lost much

of its shape, but little if any of the housing seemed to have been lost to

vaporization. It therefore seems highly unlikely that the plastic material of

the smoke detector will contribute a life or health threat to building occupants.

The other non-radiological components of smoke detectors consist of

circuit boards and semiconductor material, photoelectric apparatus, wiring,

stainless steel plates and screws, and in some units a 9-volt battery. These

electronic components could contain any or all of the following:

3-72
Germanium, Silicon, Zinc, Sulfur, Phosphorous,

Cadmium, Mercury, Lead, Arsenic, Copper, Silver,

Gold, Selenium, Tellurium, Thallium, Phenolic Resins

Some of the elements in these electric components are highly toxic

(e.g., Cd, Hg, Pb, As) and for industrial exposures, can have slow cumulative

action.

In the smoke detector units the average circuit board is no more than

three inches by three inches and weighs about three grams (0.1 ounce). The

boards are made of epoxy resin and glass with copper on their surface. These

boards are made to pass UL tests and therefore, do not support combustion. The

basic semiconductor material is silicon which is doped with specific elements in

molecular amounts. Silicon is a vital trace material in the human body (0.026

percent per body weight( 6 4 ), When silicon is combined with oxygen it becomes

silica (silicon dioxide), a material which is responsible for silicosis, a

chronic fibrotic pulmonary disease. For this disease to develop, prolonged

exposure is required, an exposure situation which is not the type that would

develop under the presently considered circumstances.

Slight, if any potential nonradiological impact can be seen for

residential smoke detectors. For a typical residential installation (two

detectors) the event probabilities involved in exposing the building occupant to

toxic nonradiological products from the smoke detector would be an occurrence of

extremely small consequences.

3-73
41.
4. ALTERNATIVES

The previous section dealt with the environmental impact of ICSD's with

Am-241. This section deals with alternatives to present day Am-241 ICSD's.

Those alternatives considered are as follows:

1. ICSD with less Am-241

2. ICSD with Ra-226

3. ICSD with Ni-63

4. Photoelectric detector

5. Combination unit

6. "Tube bundle" detector system

7. Taguchi semiconductor gas sensor

8. Thermal sensors

4.1 ICSD WITH Am-241

An obvious way to reduce the radiological hazards of Am-241 ICSD's is

to scale down the amount of activity in each detector. Any reduction in activity

would reduce the radiological environmental impacts in a linear fashion. Table

2.3 illustrates the reduction that has taken place in average ICSD activity since

1975. It appears that 1 uCi per unit will become standard in general. Reduction

below this level is not easily quantified at this time.

It has been pointed out that to develop a smoke detector with minimum

amounts of radioactive material, specifically 0.3 uCi, there is a demanding

engineering requirement to the electronics of the unit in that the sensitivity

must be increased to 3 to 5 times that of todays commercial product( 6 5 1 . Since

the ion current at 0.3 uCi will be very low it is felt that the physical design

of the unit will have to be fairly open. This becomes a particle entry problem

in terms of false alarms which in turn requires very sophisticated electronics.

An approach to developing units that contain less radioactive material requires a

more precise understanding of smoke detection and smoke detectors. Mathematical

4-1
approaches to this level of understanding are becoming more important as the

smoke detector field gains maturity. Charles D. Litton of the

U. S. Bureau of Mines has published a series of reports that is based on a

mathematical approach to the design and function of smoke detectors( 6 6 "

6 8 ). In

one of his latest publications( 6 7 ). Litton has employed reduced source

approximations to a somewhat standardized ICSD chamber and has shown the optimum

source for the unit to be 0.3 uCi of Am-241. This is a signftcant reduction in

Am-241 and points to the importance of developing and refining the theories of

fire and fire detection.

4.2 ICSO WITH Ra-226

Ra-226 ICSD's have been distributed in the past. Table 2.5 illustrates

the past distribution of Ra-226 ICSD's by company. The range of activity is from

0.05 to 1.5 uCi per unit. The majority of the units contained 0.05 uCi per unit.

Am-241 ICSD's today have essentially replaced Ra-226 ICSO's in the market.

Ra-226 ICSD's are very similar in design to their Am-241 counterparts. The

source foils are constructed in much the same way as the Am-241 foils. The basic

difference is the activity compound is radium sulfate instead of americium oxide.

The radiological parameters for Ra-226 are listed in Table 2.1. The

dose rate at one meter for an uncovered Ra-226 source is 8.3 x 10-1 uR/hr per uCi

of Ra-226. For Am-241 it is 1.2x10"2.uR/hr per uCi. The ratio of the two is

about 70. The calculated mean weighted gamma-ray energy of Ra-226 in equilibrium

with its daughter products is about 0..75 MeV. Thus, the amount of attenuation

occuring within the ICSD housing and components would be somewhat less than that

of the 0.06 MeV gamma-ray of Am-241. The organ dose conversion factors for

external radiation sources would also be higher for Ra-226. The net effect of

the above factors is that the external radiation dose from a Ra-226 ICSD is about

90 times higher than the external radiation dose from a similar Am-241 ICSD

containing the same amount of activity.

Tests have shown that less than five percent of Ra-226 activity is

released from incineration at 9250C( 6 g). The incineration of one-tenth of the

Ra-226 ICSD's disposed of at the rate of 106 per year is assessed here assuming

the same conditions as in the Am-241 case, except for the average activity per

detector (0.05 uCi) and the maximum activity release (five percent).

4-2
The total activity released in a year would be

(lxlO6 unlts)(0.05 uCl/unlt)(0.1)(O.05)(0.1) = 25 uCi

or about 0.08 uCI per incinerator. Using the same assumptions for incineration

as used for the Am-241 analysis In Section 3, the concentration of radium in the

stack gases would be about 1.9xi0"16 uCl/cm3 , which is about ten thousand times

lower than the standard for Ra-226 concentrations in air in unrestricted areas.

-The maximum downwind ground level concentration would be

(2.6x10"9 uCi/s)(2x1O- 5 s/m3 )

= 5.2x10-14 uCi/m 3

The amount of activity inhaled by a person continuously breathing air of this

concentration would be about 3.8xI0"1 0 uCi per year. The intakes-and associated

organ doses for the reference population groups are given in Table 4.1.

4.3 ICSD WITH ti-63

When the residential ICSD industry was in its infancy about seven or

eight years ago, a consideration as to the type of source material to be used was

addressed by some manufacturers. Those manufacturers who considered Hi-63 as a

source at that time were for the most part rather quickly discouraged. A primary

problem in considering Ri-63 was that little previous work had been done in the

use of this nuclide in a consumer product and therefore the initial cost of such

development was considered prohibitive, especially when Ra-226 or Am-241 were

available and considerable documentation of their use and hazards had been

developed. Mti-63 is found at the present time In a smoke detector employed for

commercial applicatons but not in a consumer-oriented product. There is, at

present, a company developing a Ni-63 detector for the consumer market.

4-3
Table 4.1 Comparison of Inhalation Dose Commitments

Resulting from Incineration of ICSD's with

Different Radionuclides.

!

Dose (per 106 ICS'DS)a

Reference

Case Radlonuclide Intake (uCi) Total Body Kidneys Liver Bone Lungs

Maximally N1-63 1.2E-12 4.7E-15 - l.OE-14 1.5E-13 1.4E-14

Exposed

Individual Ra-226 3.BE-10 7.4E-8 2.6E-11 9.1E-13 1.OE-7 3.9E-8

(rem)

Am-241 3.3E-10 7.9E-9 6.2E-8 1.1E-7 l.IE-7 1.9E-7

Population NI-63 3.1E-8 1.2E-10 - 2.5E-10 3.7E-9 3.4E-10

Around

Incinerator Ra-226 9.5E-6 1.9E-3 6.SE-.7 2.3E-8 2.5E-3 9.8E-4

(person-rem)

Am-241 8.3E-6 2.1E-4 1.6E-3 2.6E-3 2.8E-3 4.4E-3

Total N1-63 9.3E-6 3.5E-8 - 7.6E-8 l.1E-6 l.OE-7

Exposed

Population Ra-226 2.9E-3 5.7E-1 2.OE-4 7.OE-6 7.5E-1 2.9E-1

(person-rem)

Am-241 2.5E-3 5.9E-2 4.4E-1 7.9E-1 7.9E-1 l.2E+O

a. Assumes particle size of 1 micron and solubility class W for Ni-63 and Ra-226,

and Class Y for Am-241.
The construction of a Ni-63 source is different than the Ra-226 and

Am-241 foils. The construction consists of the N1-63 electroplated as a film

coaxially on a nickel-plated monel wire. The Ni-63 is overplated with a rhodium

barrier film. A four-inch segment would include 30 uCi of Ni-63. The product

for the consumer is presently designed to contain 30 uCi of Ni-63 per unit.

Although the projected amount. of source material per smoke detector employing

Ni-63 is 30 uCi, when the maximum permissible body burden (bone) is compared with

that for Am-241 the Ni-63 has a 4000:1 advantage over Am-241( 7 0 ). These factors

would appear to give an ICSD utilizing 141-63 a reasonable chance of commercial

success in the consumer market place.

For external considerations the very low level photon emissions from

the beta source are taken to be 10 key at an intensity of 2x10"4 per Ni-63

disintegration. The resulting dose rate at one meter (assuming a point source)

would be about 1.8x10 4 uR/hr per uCi of !41-63. A source with 30 uCi of Ni-63

results in a dose rate at one meter of 5.4x10"3 uR/hr. However, because the

energy is taken to be 10 keY, the effective dose rates are much lower compared to

50 keV photons. For comparison sake, the external dose rates are taken to be

zero. No consideration of beta dose or skin dose is made at this point.

High temperature (1200 0C) testing of Ni4-63 sources has revealed that an

exttemely small fraction (less than 0.01 percent) of the source activity is

released in effluent air and by post-test wipes( 71 ). Assuming incineration of

one-tenth of the Ni-63 ICSD's disposed in a year, each containing 30 uCi of

141-63, would result in a maximum release of

(1xi06 units)(30 uCi/unit)(0.1)(0.0001)(0.1) 30 uCi

or about 0.1 uCi per incinerator. The concentration of 141-63 in the stack gases

would be about 2.3x10-16 uCi/cm3 , which is about seven orders of magnitude below

the standard for concentrations of this radionuclide in air. The maximum

downwind ground level concentration would be

(8.7x10"1 2 uCi/s)(2x10" 5 s/M3 )

4-5
= 1.7x10- 16 uCi/m 3 .

The intake resulting from continuous inhalation of air contaminated with these

levels of Ni-63 would be 1.2x10"12 uCi per year. Organ dose commitments for

exposed persons are listed in Table 4.1.

The engineering problems of source containment and electronics design,

as well as the problem of getting new designs approved, are all considerations

which limit the industry to materials presently employed. The costs to a company

to produce a new smoke detector employing new designs is more than the majority

of manufacturers are willing to bear. Even in the case of the Ni-63 units, most

manufacturers claimed to be unaware such a device is being developed for the

consumer market. A point made by these manufacturers was that once someone did

go to such a cost the others would probably follow, but few are willing to be

burdened with the initial research and development costs.

4.4 PHOTOELECTRIC DETECTOR

Photoelectric detectors for the most part operate on the

light-scattering principle. A sensing chamber contains a light source and a

light receiver. The two are arranged such that the source light normally does

not enter the receiver. When smoke particles are present in the sensing chamber,

light can be scattered into the receiver. The increase in luminous flux at the

receiver is proportional to the concentration of smoke particles in the chamber.

When the flux reaches a predetermined level an alarm is triggered. Figure 4.1

illustrates an example of light-scattering detector optics.

Early photoelectrics used incandescent bulbs for light sources. Power

requirements made line access necessary. Though incandescent bulb models are

still being made, the introduction of low-power light emitting diodes (LED) has

improved reliability. The introduction of LED light sources was basically to

reduce lamp replacement maintenance. Life expectancy of incandescent lamps was

one to three years Life. expectancy of LED light sources is greater than

thirty years.

Because of careful study of low velocity flow dynamics and the

elimination of light-tight labyrinths by means of 'electronic ambient light

4-6
TRANSISTOR

EMITTING DIODE BOARD

Figure 4.1. Photoelectric Detector Optics. 2

4-7
rejection, ease of smoke entry into photoelectric detectors has improved greatly

in recent years.

Since both ICSD's and photoelectric detectors are available in the

consumer market, comparisons have been made of their use and reliability. As to

which unit is superior is primarily related to who is describing the units.

Similar tests, such as a smoldering furniture fire, can lead to opposite results

under similar circumstances (72.73) Inquiries to some state and federal agencies

have revealed prejudices toward the ICSD units based on early reports that had

been obtained. These biases are, in many cases, admittedly based on results of

comparisons and detection requirements that no longer apply to current detector

models. But, because of these biases, there still exist some requirements or

inferred requirements towards installing ICSD's rather than photoelectric smoke

detectors. This situation exists for some major federal and state government

buildings as well as residential installations for entire states.

The sensitivity of smoke detectors to particle size has been

investigated in a joint study by the National Bureau of Standards and the

University of Minnesota( 7 4 ). A monodisperse aerosol generation system was

developed to test detector sensitivity for light-scattering type detectors

(photoelectric) and ICSD's. Figure 4.2 illustrates detector sensitivity versus

particle size for a photoelectric unit and an ICSD unit. The detector

sensitivity is defined as the detector output minus the background reading

divided by the particle concentration. The uncertainty in the sensitivity was

(2) estimated to be +30 percent

Figure 4.2 implies the ICSD unit is more sensitive, to particle sizes

smaller than 0.3 um and the photoelectric unit its more sensitive to particle size

greater than 0.3 um. Bukowski and Mullholland(2) feel important practical

implications can be concluded from this information if the work by Bankston et

al.( 7 5 ) at the Georgia Institute of Technology is considered. This work

indicated the smoke particles generated in the flaming mode of combustion for

Douglas fir, polyvinylchloride, and rigid urethane foam are generally smaller

than 0.3 um. The same materials undergoing combustion or pyrolysis in the

non-flaming mode produce particles larger than 0.3 urn. Using this information it

can be concluded that the ICSD is more sensitive to particles generated from

flaming materials while the photoelectric detector is more sensitive-to particles

generated by non-flaming materials. This has been demonstrated in various smalland large-scale fire tests(7 3 '7 6 ).

4-8
10~3

102

30

=b

mid

0'

/

'p

I

I

~' S-2

E

3.

I-m

=J

'amm

I.-

C.

'hia

I

I

I

I

I

I 10

3

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0.3'

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a I

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0

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ol

I

I

I 0.03

S .01 L

Di'

I I I 1 11111 I I I 1 11111 I

0.03 0.1 0.3 I 3

DIAMETER Ipm]

Figure 4.2. Detector Sensitivity Versus Particle Size

for a Light-Scattering Type Detector (S-2)

and for an Ionization Type Detector (R-2) 2

4-9
4.5C COMBINATION UNIT

A new alternative recently introduced on the market place is the

combination unit or "photo-ion" unit which contains both a photoelectric detector

and an ionization chamber smoke detector. The advantage of the combination unit

is the utilization of the sensitivities of both types of detectors. Quick

detection of both large and small particles can be achieved.

4.6 "TUBE BUNDLE" DETECTOR SYSTEM

The Bureau of Mines has always been concerned with the detection of

toxic gases and fires in mines and has investigated the problem on a continuous

basis. One method of combustion products detection developed by this bureau is

referred to as the "tube bundle" methoa( 77 ,78 ). This syste Im consists of a

centrally located ionizaton chamber for detecting smoke particles and a series of

tubes leading fromt the chamber to various tunnel locations. Ambient air from

each tube's distal location is pumped to the ionization chamber in a continuous

manner and thereby tested for gas and smoke particulate. This system has been

proposed as a method to be used in multi-family complexes and if it could be

shown to be cost effective it could prove to be applicable to these structures.

Since this methodology effectively removes the source material of the ionization

chamber from the inmmediate occupant's environment it.has the ability of reducing

the exposure of the public to radiation. Also, -since the actual detector

mechanism is removed from the immnediate care or misuse by the residential

occupants, some situations which have resulted in detector failure and.

fire-related occupant death will be overcome.

This alternative is presently not judged to be a practical alternative

for the residential consumer since it is more applicable to apartments or bigger

buildings.

4.7 TAGUCHtI SEMICONDUCTOR GAS SENSOR

Since all fires are basically gas fires it is reasonable to investigate

the detection of gases when discussing fire detection. One of the more

frequently mentioned gas detectors is the Taguchi gas detector. This solid-sate

Japanese instrument is used by some American manufacturers in their gas detection

products. In the Taguchi gas detector the sensing element is a metal-oxide

4-10
semiconductor which is internally heated such that the surface oxygen is in a

highly excited state. Contact of the surface with an oxidizable or reducible gas

results in a change in conductivity of the metal-oxide semiconductor. Detection

of this change indicates the presence of a gas.

Because of a standardization of the definition "smoke particle" the

Taguchi instrument and other gas detectors can not be marketed as a smoke

detector. Although the unit is intended as a gas detector it could conceivably

be used as a home fire warning device. Unfortunately, since the device is a good

gas detector, it appears to be too sensitive for home use due to the continued

release of cosmetic and other volatile consumer products. These products release

enough material to the atmosphere to cause a gas detector to register and

frequently sound false alarms. No future refinements are expected for the

Taguchi gas detector, such that it could be employed in the home, and it is,

therefore,. not expected to enter the residential fire detection consumer

market~7~

4.8 THERMAL SENSORS

Other forms of fire detection, such as rate of rise and fixed

temperature heat detectors, are available for the consumer market but these have

not been as successful as smoke detectors. Tests have been conducted which give

a significant advantage to the smoke detectors in terms of occupant escape

time(73 ). There have been objections to the manner in which the tests were

conducted, but no data was found- which supports the heat detectors as the

instrument of choice for a residential fire warning device 80 . Until further

tests can be conducted under simulated residential fire conditions that show an

equal or superior performance for the rate of rise or fixed temperature devices,,

it appears that the consumer market for fire warning devices will continue to be

dominated by some form of smoke detector.

4-11

5. COST AND RISK VERSUS BENEFIT ANALYSIS

5.1 GENERAL

The acceptability of levels of radiation exposure for certain

activities has been determined using cost-benefit. analysis in the past.

Risk-benefit analysis also helps to determine the acceptability of levels of

radiation exposure. Two questions are posed by such analysis:

1. What is the incremental cost to incrementally reduce

exposure?

2. How much benefit is received as opposed to risk?

In regards to the first question, it is obvious that if no substantial exposure

reduction can be made by spending a rglatively large amount of money, the cost is

not Justified. In regards to the second question, if benefits acquired far

outweigh the risks (benefits and risks being equated) the level of exposure

should be judged acceptable.

Benefits are often hard to quantify since some benefits may be tangible

while others may be intangible. The National Environmental Policy Act (NEPA) of

1969 states that "for purposes of complying with the Act, the weighing of the

merits and drawbacks of the various alternatives need not be displayed in a

monetary cost-benefit analysis and should not be when there are important

qualitative considerations. In any event, an environmental impact statement

should at least indicate those.considerations, including factors not related to

environmental quality, which are likely -to be relevant and important to a

decision."

For this report the following objectives are pursued In regards to

cost- and risk-benefit analysis. Each alternative plus the "standard* Am-241

ICSD will be compared. For the sake of comparison, reduction of person-rem

versus cost will be made. Where appropriate a risk-benefit analysis will be

5-1
made. Where radiation exposure is involved the use of health effects will be

made. The ratio of the number of lives saved in fires to the excess cancers

resulting from exposures will be given.

The smoke or fire detectors considered are:

1. ICSD with Am-241

2. ICSD with Ra-226

3. ICSD with Ni-63

4. Photoelectric detector

5. Combination unit

6. Thermal sensors

The "tube bundle" detector system and Taguchi gas sensor are not considered for

reasons given in Section 4.

5.2 COSTS

The market for smoke or fire detectors has become extremely

competitive. The cost of ICSD units has declined drastically in the last few

years. The average unit price in 1971 was $125.00 per detector while in 1977 it

was 25.0(2)

was $25.00 Recently, the price of units was changing even faster. A quick

survey of a number of retail outlet stores in a large western city found a large

spread in prices of single unit ICSD's.

For a standard ICSD with no extras such as battery backup (AC line

models) or lighrt (to see in the dark) the prices ranged from a low of $6.99 to a

high of $29.99. Extra features added to the price. In-general AC-line cord

models were found to be slightly less expensive than battery models. Of the 15

to 20 models observed, only two were of the photoelectric type. Another was a

combination unit with both a photoelectric detector and ionization chamber. Both

photoelectric detectors were $19.99. The combination unit was $29.99. Other

units contained extra features such as test buttons, heat sensors, lights to

light the way in case of darkness, and battery backups for AC-line models. One

heat detector (set at 1350 F) was found to cost $19.99.

For purposes of comparison the following prices are considered to be

typical for the units listed. The numbers are based upon the survey discussed

above and educated guesses for such units as the Ni-63 ICSD (not available to the

consumer):

5-2
1. ICSO with Am-241 $12.00

2. ICSD with Ra-226 $12.00

3. ICSD with Ni-63 $15.00

4. Photodetector $20.00

5. Combination unit $30.00

6. Thermal sensor (complete unit) $20.00

5.3 BENEFIT VERSUS RISK FOR Am-241 ICSD'S

A broad summary of risks has recently been developed and assembled by

Cohen and Lee( 8 1 ). (See Table 5.1.) The data was developed on a "days of life

expectancy lost" basis to facilitate the understanding of risk by the general

public. Near the very bottom of the table can be found the category "smoke alarm

in home." For smoke alarms, Cohen and Lee indicate an increase in life

expectancy. This assumption is based on the idea that residential fires reduce

the average life expectancy by 27 days and that residential smoke alarms would

reduce this value by approximately one-third or ten days. This sort of risk

assessment is far from definitive when trying to analyze the full impact of a

product but serves to give some perspective of the level of risk being discussed.

For the purposes of comparison, the benefits derived from ICSD's and

other smoke detectors are lives saved and property damage loss reduced. For

ICSD's the risk associated with their use is the resultant dose commitments and

potential health effects.

The potential number of lives that may be saved by smoke detector usage

is discussed in Section 3.1. In the United States it is estimated between 5250

and 8400 lives are lost in residential fires each year. This is roughly 70

percent of all fire deaths in the United States. The estimates for a life-saving

factor for smoke detectors range from 41 to 89 percent. This corresponds to

between 2150 and 7500 potential lives saved each year if the total population

(220 million people) utilizes smoke detectors. The best estimate of the life

saving factor for smoke detectors is 50 percent(14). The range of potential

lives saved for 50 percent would be from 2600 to 4200.

The potential for saving property was estimated in Section 3.1 to range

from 33 to 68 percent for residential fires. For 1976, assuming two-thirds

utilization of smoke detectors, the potential for property saved ranged from 310

to 638 million dollars. Fourteen million detectors would account for between 44

5-3
Table 5.1. Loss of Life Expectancy Due to Various Causes.

Cause Days

Being unmarried - male 3500

Cigarette smoking - male 22S0 Heart disease 2100 Being unmarried - female 1600 Being 301 overweight 1300 Being a coal miner 1100 Cancer 980 201 Overweight 900 <8th grade education 850 Cigarette smoking - female 800 Low socioeconomic status 700 Stroke 520 Living in unfavorable state 500 Army In Vietnam 400 Cigar smoking 330 Dangerous Job - accidents 300 Pipe smoking 220 Increasing food intake 100 cal/day 210 Motor vehicle accidents 207 Pneumonia - influenza 141 Alcohol (U. S. average) 130 Accidents in home 95 Suicide 95 Diabetes 95 Being murdered 90 Legal drug misuse 90 Average jobs - accidents 74 Drowning 41 Job with radiation exposure 40 Falls 39 Accidents to pedestrians 37

Safest Jobs - accidents 30 Fires - burns 27 Generation of energy 24 Illicit drugs (U. S. average) 18 Poison (solid, liquid) 17 Suffocation 13 Firearms accidents 11 Natural.radiation (BEIR) 8 Medical X-rays 6 Poisonous gases 7 Coffee 6 Oral contraceptives 5 Accidents to pedalcycles S All catastrophes combined 3.5 Diet drinks 2

Reactor accidents - UCS 2* Reactor accidents - Rasmussen 0.02* Radiation from nuclear industry 0.02* PAP Test -4 Smoke alarm in home -10 Air bags in car -50 Mobile coronary care units -12S Safety improvements 1966-76 -110

*These items assume that all U. S. power Is nuclear. UCS is Union of

Concerned Scientists, the most prominent group of nuclear critics.

5-4
and 91 million dollars. At a cost of twelve dollars per Am-241 ICSD, the initial

cost of fourteen million detectors is 168 million dollars. Without doing a full

economic evaluation (which is not Justified), it is seen that the Am-241 ICSD's

will easily be cost-effective over their ten-year life in terms of initial cost

compared to potential property savings.

Table 3.20 summarized the total health effects from the manufacture,

use, and disposal of 14 million Am-241 ICSD's. Fourteen million units represents

the peak distribution year (1978). The total fatal cancers were found to be

0.14. The total body dose was found to be 1100 person-rem.

Fourteen million smoke detectors would service about 21 million people

if every residence is assumed to have two detectors and three occupants.

Therefore, the potential life-saving per year by 14 million smoke detectors would

range from

21x10 6 /220x10 6 x 2150 - 210 lives/year

to

21xlO6/220x10 6 x 7500 = 720 lives/year.

Assuming a 50 percent life-saving factor, the range would be 250 to 400 lives

saved per year. If the useful lifespan of a smoke detector is ten years, the

number of lives saved would range from 2100 to 7200 in ten years. The best

estimated range would be from 2500 to 4000 lives saved.

Considering benefit-to-risk with lives saved as the benefit and

estimated cancer mortalities as the risk, the benefit-to-risk ratio for Am-241

ICSD's is found to range from

2100/0.14 = 15,000 lives saved/mortality

to

7200/0.14 = 51,000 lives saved/mortality.

The best estimated range would be from 18,000 to 29,000 lives saved per

mortality.

5-5
5.4 ANALYSIS FOR ALTERNATIVES

5.4.1 General

Section 4 discussed alternatives to present-day AM-241 ICSD's. In

order to assess alternatives, a basis or bases must be established on which to

judge alternatives compared to Am-241 ICSD's. A major part of the analysis to

follow concerns cost-versus-reduction in radiation exposure. Section 3 discussed

the radiological consequences of Am-241 ICSD use. Section 4 discussed the

radiological aspects of ICSD alternatives. Alternatives without radioactive

material, of course, produce no radiological consequences. There is no basis for

non-radiological consequences and it is felt the difference between these

consequences for different alternatives would be indistinguishable.

The total body dose due to the manufacture, use, and disposal of 14

million Am-241 ICSD's was found to be 1100 person-rem. On a per unit basis the

total body dose per detector is 7.9x10"5 person-rem. Therefore, if an

alternative with a negligible radiological impact compared to an Am-241 ICSD is

utilized, 7.9x10"5 person-rem is the dose reduction realized by using the

alternative. The cost of reducing the 7.9x10"5 person-rem is simply the cost

difference between the alternative and the Am-241 ICSD. This canbe represented

in equation form as follows:

COR zAC/AD

where CDR = cost of dose reduction ($/person-rem),

&C =cost of alternative - cost of Am-241 ICSD($),

AD = dose reduction (person-rem).

If the dose reduction is assumed to be 7.9x1O"5 person-rem, then

CDR = AC/(7.9xlO" 5 person-rem).

Figure 5.1 illustrates this equation.

Estimates( 8 2 ) of the monetary value of avoiding the detriment possibly

associated with a collective dose of one person-rem have been attempted in the

past. Although all estimates are subjective in nature, the range is from 10 to

5-6
10 6

LU,

0

4^

U.'

LU

VI

U.

d,,

0 5 10 15 20 25

&C (M)

Figure 5.1. Cost of Dose Reduction for Alternatives

versus Am-241 ICSD.

5-7
250 dollars per person-rem. If 1000 dollars per person-rem is used as the point

at which an alternative is viable (10CFR50, Appendix I used this value for total

body person-rem accumulated within 50 miles of a nuclear power plant), then the

corresponding AC is found to be

AC = (7.9x10-5 person-rem) ($1000/person-rem)

= $0.08.

Essentially, the alternative must cost within $0.08 of the Am-241 ICSD if $1000

per person-rem is used as the criteria.

In the following discussion of alternatives, the cost of dose reduction

will be used where appropriate.

5.4.2 Am-241 ICSD's with Less Activity

A reduction of activity in Am-241 ICSD's has occurred over the past

years.. As technology improves, the amount will continue to decrease. A

correlation between cost and reduction is not possible at this time. However,

any reduction in activity that has little impact on the cost will lower estimated

doses and dose commitments. Therefore, such an Am-241 ICSD would be a better

alternative to present Am-241 ICSD's with more activity.

5.4.3 Ra-226 ICSD's

In Section 4.2 it was estimated that the external exposure from Ra-226

sources was about 90 times higher than for equal amounts of Am-241. However,

Ra-226 ICSO sources typically contain significantly less activity than Am-241

ICSD sources. Table 2.5 indicates 0.05 uCi of Ra-226 to be the most common

amount of activity. Since the average Am-241 is 3 uCi per ICSD, there is about

sixty times more activity in the reference Am-241 ICSD as compared to the Ra-226

ICSD. The resulting external doses from use of the Ra-226 ICSD's would only be

about 50 percent higher than for similar use of Am-241 ICSD's.

If it is assumed ICSD's can be constructed using smaller amounts of

Ra-226 than 0.05 uCi then the resulting external doses would be essentially the

same as for the reference Am-241 ICSD's. Thus, the decision as to whether the

Ra-226 ICSD is a good alternative to the Am-241 ICSD would have to be made based

5-8
upon other criteria. One consideration is the relative half-lives. The

half-life for Ra-226 is 1620 years while the half-life for Am-241 is 458 years.

Am-241 is more favorable in this comparison, since it will not persist in the

environment as long as Ra-226.

Another consideration is that Radon-222 (Rn-222), a gas, is a daughter

product of Ra-226. Small amounts of Rn-222 are released from the Ra-226 sources.

Measurements of radon emanation from Ra-226 foils have been made by Hall and

Hunt 18 ). They found the emanation at room temperature to be as high as 1.7x10 2

nCi per day from a 0.66 uCi source. At higher temperatures the release was found

to be in the hundreds of nCi per hour. Though the releases are small, the

release of Rn-222 is considered a negative aspect of Ra-226 use in ICSD's. The

Rn-222 decays into ridioactive non-gaseous daughters which emit penetrating

radiation.

Therefore, based upon the above considerations, Ra-226 does not appear

to be a good alternative to Am-241 for use in ICSD's.

5.4.4 Ni-63 ICSD's

The external doses from proposed Ni-63 ICSO's are extremely low

compared to Am-241 ICSD's. Resultant dose commitments from incineration are

found to be orders of magnitude below similar incineration of Am-241 ICSD's.

Therefore, radiologically, the Ni-63 ICSD is found to be better in terms of dose

compared to Am-241 ICSD's.

Assuming equal abilities to detect fires, the major comparison for

Ni-63 ICSD's to Am-241 ICSD's is in the cost of dose reduction. In Section 5.2,

the estimated cost of an Am-241 ICSO was stated to be twelve dollars. The cost

of a Ni-63 ICSD was estimated to be fifteen dollars. Therefore, the cost

difference between the Ni-63 ICSO and Am-241 ICSD is three dollars. The cost of

dose reduction is

CDR - $3/(7.9x10"5 person-rem)

= $38,000/person-rem.

Figure 5.1 can also be used to derive this number. A cost of dose reduction of

$38,000 per person-rem is considerably higher than the $1000 per person-rem used

for comparison in Section 5.4.1.

5-9
If $1000 per person-rem is used as the criteria for selecting an

alternative, then given the choice of an Am-241 ICSD versus a Ni-63 ICSD at

approximately the same cost, the Ni-63 ICSD is the better alternative.

5.4.5 Photoelectric Detector

Section 4 discusses the use of photoelectric detectors. The difference

in its ability to detect and warn of fires compared to ICSD's is discussed at

length. The conclusion, however, is that no firm statements can be made

regarding which detector type has the best response. Each apparently is more

sensitive to different types of fires. The ICSD reacts quicker to fast-burning

fires while the photoelectric detector reacts quicker to smoldering or

slow-burning fires. If the responses do follow the above conclusion, it is felt

that the ICSD unit may have a slight edge over the photoelectric detector since

response is more critical to fast-burning fires. Also, since the circuitry of

photoelectric detectors is slightly more complex than ICSD's, (given both source

and receiving components) the reliability may be correspondingly less than for

ICSO's. However, supporting data is lacking.

Because supporting data is not available for comparison, it is assumed

photoelectric detectors respond to fires equally well when compared to ICSD's.

Using Figure 5.1, it can be seen (assuming as give` in Section 5.2 that the

photoelectric detector costs twenty dollars or eight dollars more than an Am-241

ICSD) that the cost of dose reduction for present photoelectric detectors is

$100,000 per person-rem. Again, to be viable, it must cost approximately the

same as the Am-241 ICSD.

5.4.6 Combination Unit

The "photo-ion" unit contains both a photoelectric detector and an

ICSD. It definitely offers the greatest protection from fires to a consumer

because it utilizes the sensitivities of both types of detectors. The

radiological consequences should be approximately the same as the basic ICSD,

but it is at a cost disadvantage to a basic ICSD. The question that is raised

with a combination unit is' the added amount of safety. Again, the data to

support its obvious position as the best source, of protection is lacking.

5-10.
However, a very crude calculation can be made to try to evaluate how many

additional lives combination units must save to be cost effective.

Section 5.3 stated the total fatal cancers due to the manufacture, use

and disposal of 14 million Am-241 ICSO's was found to be 0.14. The total body

dose was found to be 1100 person-rem. Crudely equating the fatal cancers (0.14)

to the collective total body dose (1100 person-rem), one fatal cancer would

result from 7900 person-rem total body. Using the cost of dose reduction

criteria of $1000 per person-rem, then the cost of a saved life would be

(7900 person-rem/life) ($1000/person-rem)

= $7.9xlO6/life.

The cost of a combination unit is given as thirty dollars in Section 5.2. It,

therefore, costs eighteen dollars more than the Am-241 ICSD. Using the $1000 per

person-rem cost of dose reduction criteria, the additional cost of the

combination units can be equated to additional lives saved. The additional cost

of using 14 million combination units ($18 per unit) divided by the

crudely-calculated value of life ($7.9x1O6 ) would be the number of additional

lives that must be saved, or

(14x1O6 units)($18/unit)/($7.9xl0 6 /life)

= 32 lives.

Therefore, for the combination units to be cost effective, they must save at

least 32 additional lives. (Fourteen million units used for ten years). The

estimated range of lives saved using 14 million Am-241 ICSD's for ten years was

found to be 2100 to 7200. An additional 32 lives saved is found to represent 0.4

to 1.5 percent of the estimated lives saved. Thus, if the combination units are

found to be greater than 1.5 percent more effective than Am-241 units, they would

be cost-effective as an alternative.

5.4.7 Thermal Sensors

Section 4 states thermal sensors alone are at a significant

disadvantage to smoke detectors. Since their cost is higher than ICSD's by about

5-11
the same amount as photoelectric detectors, they are judged not to be a viable

alternative to Am-241 ICSD's.

5.5 CONCLUSIONS

The cost-to-benefit ratio for presently manufactured Am-241 ICSD's is

of such a magnitude as to make the use of these detectors a justifiable use of

radioactive material by the consumer. If the development of Ni-63 ICSO's results

in a product of comparable sensitivity and cost, the Ni-63 ICSO should be

considered the better option. The use of Ra-226 ICSD's is not judged to be a

better alternative to Am-241 ICSD's because of a longer half-life and because of

emanation of Rn-222.

Because of an apparent difference in response to fires by photoelectric

detectors as compared to ICSD's and because of its greater cost, the

photoelectric detector is not judged to be a better option to ICSD's. However,

if future data were to show it was comparable to ICSD's in overall response, and

if its cost became comparable to ICSD's, it would be considered the better

option.

The use of the combination unit cannot be justified or dismissed as a

better or worse option to ICSD's because data is lacking on its life-saving

advantage over ICSD's. However, the unit is considered to offer the greatest

degree of fire protection available to the consumer in a single unit. If the

life-saving effectiveness of combination units is found to be greater than the

effectiveness of Am-241 ICSD's by a considerable amount, their use is cost

effective. Crude calculations showed this amount to be only 1.5 percent.

5-12
6. FUTURE PRODUCTS

Predicting trends in fire detection equipment to be used in the future

can only be an educated guess. Based upon trends during the past ten years, it

is obvious that the use of early fire warning products such as ICSD's has become

widespread and the public has accepted the need based upon the derived benefits.

The development of ICSD's has shown tremendous progress both in terms

of economics and sophistication. Today's units have been engineered with many

features that provide greater sensitivity and reliability. Photoelectric

detector development, though lagging behind ICSD's, has begun to reach new levels

of sophistication.

Smoke detector manufacturers were quick to take advantage of the

advances in microelectronic components. At the present stage of technology some

units are in the fourth generation of MOS-FET chip design. This technology

offers a number of advantages including a wide range of operating voltages,

ability to detect an extremely broad range of slight changes in voltages,

extremely small size, and substantial reduction in manufacturing costs. At least

two manufacturers are developing advanced chips for use in photoelectric smoke

detectors which should lead to a reduction in price of these units and thus a

more competitive position in the consumer market.

Units are appearing, or will soon, that communicate with each other by

means of a radiofrequency transmission. Some units will inform the occupant, by

means of a difference in warning signal, whether they are in the room that is the

source of the hazard or if it is in another location. This ability to detect in

one area and set off warnings in all areas is being combined with intrusion

alarms as a more total home security system. Since the circuits for smoke

detectors read a shift in signal level they lend themselves well to intrusion

alarming. Some manufacturers have gone so far as to indicate a potential future

unit that incorporates a microprocessor to perform numerous functions as a result

of various signals.

6-1
The new electronics employed in smoke detectors is leading to greater

sensitivities along with a reduction in false signals. Chip technology allows

for greater freedom in signal detection such that a detector can count occurances

over a period of time and only sound an alarm when a significant number of events

occur. Such systems could turn on lights for people who can see and cause lights

to blink for people who are deaf.

Integrated circuitry for smoke detectors does not improve the smoke

detectors without creating some problems. A significant shortcoming of chip

design, as pointed out by more than one manufacturer, is that the detector field

is always changing. Regulations are not the same from country to country and

regulations within the same country are also changing. As the state-of-the-art

changes, new requirements are placed on the IC design. Trends of this nature

lead to IC's in the form of custom chips and there are considerable cost factors

to constantly changing chip design. Not all manufacturers can afford the

research and development cost and, therefore, the chips begin to come under the

control of only a few manufacturers.

The distribution of ICSO's in the near future (to 1987) is of great

interest to manufacturers and distributors. Based upon discussion with a number

of manufacturers, it appears the market will start to decrease as saturation

begins to take place. The years of 1978 and 1979 should prove to be peak years

with a down trend to follow. One estimate of ICSO distribution is given in

Table 6.1. This estimate is based upon the assumption that photoelectric

detectors will not replace ICSO's to any significant degree in the future. Also

Ni-63 ICSD's are assumed not to be on the market. Figure 6.1 illustrates the

actual number of Am-241 units distributed from 1972 to 1978 and the estimated

distribution from 1979 to 1986. Figure 6.2 illustrates the amount of Am-241

distributed, actual and projected, for the same time period. Figure 6.3

illustrates the average amount of Am-241 per unit, actual and projected, for the

same time period.

6-2
Table 6.1. Estimated Future Distribution

of Residential ICSD's.

Year Units Distributed (millions)

1979 12

1980 10

1981 8

1982 8

1983 8

1984 7

1985 6

1986 5

Total (1979-1986) 64

6-3
LC

U-)

F3

.-- 1

C.]

>-4

z

D)

15.0

14.0

13.0

12.0

11.0

10.0

9.0

8.0

7.0

6.0

100.0

90.0

80.0 -

Uo)

ZC)

70.0

6---

60.0

->

50.0 *_-

LT)

40.0

C-A 30.0 o7-

20.0 -)

10.0

0.0

Ch

4.0

3.0

2.0

1.0

0.0

19721973 1974 1975 1976 1977 1978 1979 1980 1981 1982

YEAR

Figure 6.1. Distribution of Am-241 ICSD Units - Actual

(1972-78) and Projected (1979-86).
1Si.0

LLrIDLLU 220.0

40.0- o- PER YEAR

o CUMULATIVE 200.0

- 180.0

(fl LI,

Li 30.0 160.0

Ck-

(-. 140.0

25.0-

Li 120.0 (-,

"• 20.0 7D

>" 100.0

- 15.0 - 80.0

CE:60.0 >

10.0 - 0 .

C-)

40.0 CI:

20.0

0.0 - __"-_- 0. 0

19721973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1981 1985 1986

YEAR

Figure 6.2. Distribution of Am-241 ICSD Activity - Actual

(1972-78) and Projected (1979-86).
7.0

Li

C.)

CD

(-"

cc

>-

aLi

F-'

Cc C-)

6.0

5.0

4.0

3.0

2.0

1.0

LEGEND

3 -- YEFIRLY AVERAGE

o - CUMULAITIVE A9VERAGE

6.0 c)

(..3

C-)

5.0 x

C-)

E4-)

1. 0 xi

Li 3.0I:

I-.

2.0 D

1.0>

(-4

F-a

0.0 C'-

(r

0'I

0.0

1 1982 1983 1984 1985 1986

Figure 6.3. Average Activity per Am-241 ICSD - Actual (1972-78)

and Projected (1979-86).
7. REFERENCES

1. Pish, M. D., et

Detectors," Final

al., "Evaluation of

Report, CPSC-C-77-0074,

Voluntary Standards

February 1979.

for Smoke

2. Bukowski, R. W.

Properties," NBS

and G. W. Mulholland, "Smoke Detector Design and Smoke

Technical Note 973, November 1978.

3. "Guides for Naturally-Occurring and Accelerator-Produced Radioactive

Materials (NARM)," HEW Publication FDA-77-8025, July 1977.

4. Johnson, J. E., "Smoke Detectors

Radioactivity in Consumer Products,

Containing Radioactive Materials," in

NUREG/CP-O01, August 1978.

5. McGuire, J. H. and B. E. Ruscoe, "The Value of

Home," Fire Study #9, Ottawa, Ontario, National

Division of Building Research, December 1962.

a Fire Detector in the

Research Council of Canada,

6. California Fire Incident Reporting System, "1977 Annual Report," State Fire

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7. California Fire Incident Reporting System, "1978 Annual Report," State Fire

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8. Kane, A., Acting President,

Personal Communication.

California Automaic Fire Alarm Association,

9. "Assessment of the Potential Impact of Fire Protection Systems on Actual

Fire Incidents," U. S. Department of Commerce, NFPCA Grant #76045, October

1978.

10. Ontario Housing Corporation, Ministry of Housing, "Smoke Detectors in

Ontario Housing Corporation Dwellings," Ontario, Candada, January 1978.

11. Ontario Housing Corporation, "Fire Statitics 1978,"

April 1979.

12. Wilson, R., "On Residential Fire Detection," Present

Code Commission, Commonwealth of Massachusetts, January

Ontario, Canada,

ation to the Building

20, 1976.

13. Wilson, R., "Computer Analysis of

Purchase in Massachusetts," For:

January 28, 1976.

Data on Fire Detectors Available for

Fire Prevention, Fire Protection Board,

7-1
14. Statement by Representative of National Bureau of Standards at NFPA Annual

Meeting, St. Louis, Mo., 1979.

15. U. So Department of Commerce,

Statistical Abstracts for the United States 1977, Washington D. C.

16. Nuclear Energy Agency, Organization for Economic Co-operation and

Development, "Recommendations for Ionization Chamber Smoke Detectors in

Implementation of Radiation Protection Standards," Paris, France, 1977.

17. U. S. Department of Commerce, Statistical Abstracts for the

United States 1975, Washington D. C.

18. Hall, E. G. and D. G. Hunt, "Integrity Testing of Alpha-Foil Used in

Ionization Chamber Smoke Detectors," TRC Report No. 379, September 1975.

19. Smith, 0. A., et al., "Ionization Type Smoke Detectors," Information Report,

USNRC, SECY 78-492, September 7, 1978.

20. Final Environmental Statement on the Transportation of Radioactive Material

by Air and Other Modes, USNRC, NUREG-0iMo, VO1. 1, December 191!.

21. Peterson, J. R., "Stacking Test for External Exposure," performed for BRK

Electronics, Aurora, Ill., Amended May 19, 1978.

22. General Electric Company, "Application for Specific License Authorizing

Distribution of GE Model 8201 and 8202 Smoke Detectors," December 18, 1974.

23. Harris, K., Pittway Corporation, Aurora, Ill., Personal Communication.

24. U. S. Environmental Protection Agency, Office of Solid Waste, "Solid Waste

Facts," SW-694, Washington 0. C., May 1978.

25. U. S. Department of Health, Education, and Welfare, Public Health Service,

"Quad City Solid Wastes Project - An Interim Report," Cincinnati, Oh, 1968.

26. National Center for Resource Recovery, Inc.,

"Incineration: A State-of-the-Art Study," 0. C. Health and Co., Lexington,

MA, 1974.

27. Mantell, C. L., Solid Wastes: Origin, Collection, Processing, and Disposal,

John Wiley and Sons, Inc., New York, 1975.

28. Hickman, H. L., in Energy and Resource Recovery from

Industrial and Municipal Solid Wastes, G. F. Kroneberger, Ed., AIChE

Sy-mposium Series 73UZ) :1-6, New York, 1977.

29. U. S. Environmental Protection Agency, Office of Solid Waste Management

Programs, The Report to Congress: Waste Disposal Practices

and Their Effects on Ground Water, EPA-57019-77-O01, Washington D. C.,

January 19M1.

7-2
30. Murray,

States in

Reference

C. R.

1970,'

29, p16

and E. B. Reaves, "Estimated Use of Water in the United

U. S. Geological Survey, Circular 676, reported in

31. U. S. Geological Survey, Water Supply Division, Unpublished Data, reported

in Reference 29, p24.

32. Johnson, J. E., "Comment on Congressional Bill to Prohibit the Interstate

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Manufacturers, Western Radiation Consultants, Inc., April 3, 1978.

33. Wrenn, M. E. and N. Cohen, "Dosimetric Implications of

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Society Twelfth Mid-Year Topical Symposium on Low-Level

Management, Williamsburg, VA, February 11-15, 1979.

Am-241 in Smoke

the Health Physics

Radioactive Waste

34. Cutshall, N. H., I. L. Larsen, and F. N. Case, "High Temperature Testing

of Smoke Detectors Sources," ORNL/NUREG/I1M-246, Oak Ridge National

Laboratory, Oak Ridge, TN, 1978.

35. Cline, J. F., "Uptake of Am-241 and Pu-239 by Plants," BNWL-CC-925, Pacific

Northwest Laboratories, Richland, WA, 1966.

36. Hajek, B. F., "Plutonium and Americium Mobility in Soils,"

Pacific Northwest Laboratories, Richland, WA, 1966.

BNWL-CC-925,

37. Wenzel, L. K.. "Methods for Determining Permeability of Water-Bearing

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40. Killough, G. G., et al., "INR84 - A FORTRAN Code Which Implements ICRP 2

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Laboratory, Oak Ridge, TN, 1975.

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New York University Medical Center, 1978.

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Agricultural Economics, "Agricultural Practices Which Could Enhance Solar

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Laboratories, Albuquerque, NK, 1978.

43. Chamberlain, A. C., "Interception and Retention of Radioactive Aerosols by

Vegetation," Atmospheric Environment, , 57, 1970.

.7-3
44. Chamberlain,

Atmoshphere

AERE-R 4870,

A. C. and

to Ground,"

1965.

R. C. Chadwick, "Transport of Iodine from

United Kingdom Atomic Energy Authority, Report

45. Martin, W. E., "Losses of Sr-90, Sr-89, and 1-131 from Fallout-Contaminated

Plants," Radiation Botany, 4, 275, 1964.

46. Middleton, L. J. "Radioisotopes in Plants: Practical Aspects of

Contamination with Strontium-90 and Cesium-137,"

Radioisotopes in the Biosphere, R. S. Caldecott and L. A. Snyder,

University of Minnesota, Minneapolis.

Aerial

in

Eds.,

47. Milbourn, G. M. and R. Taylor, "The Contamination of Grassland with

Radioactive Strontium. I. Initial Retention and Loss," Radiation Botany,

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48. Pelletier, C. A. and J. D. Zimbrick, "Kinetics 'of Environmental

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Proc. Symp. Environmental Surveillance in the Vicinity of Nuclear

Facilities, January 24-26, 1968, Augusta, GA, W. C. Reinig, Ed.,

Charles G. Thomas, Springfield, IL, 1970.

49. Price, K. R., "Uptake of Neptunium 237, Plutonium 239, Americium 241, and

Cerium 144 from Soil by Tumbleweed and Cheatgrass," BNWL-1688, Pacific

Northwest Laboratories, Richland, WA, 1972.

50. Ng, Y. C., et al., "Prediction of the Maximum Dosage to Man from the Fallout

of Nuclear Devices. IV. Handbook for Estimating the Maximum Internal Dose

from Radionuclides Released to the Biosphere," UCRL-50163, Part IV, Lawrence

Livermore Laboratory, Livermore, CA, 1968.

51. Mishima, J. and L. C. Schwendiman, "Fractional Airborne Release

(Representing Plutonium) During thp Burning of Contaminated

BNWL-1730, Pacific Northwest Laboratories, Richland, WA, 1973.

52. Bennett, B. G., "Fallout Pu-239 Dose to Man," in

Fallout Program Quarterly Summary Report, HASL-278, 1975.

of Uranium

Wastes,"

53. Wilson, D. G., in

and Municipal Solid Wastes, G

73(162):16-30, New York, 1977.

Energy and Resource Recovery from Industrial

.F. Kroneberger, Ed., AIhE Symposium Series

54. Achinger, W. C. and L. E. Daniels, EPA Publication PB-216-372, 1970.

55. Niessen, W. R.,

Incineration,"

USHEW Contract

"Systems Study of

Report to National Air

CPA-22-69-23, 1970.

Air Pollution from Municipal

Pollution Control Administration,

56. Rubel, F. N., Incineration of Solid Wastes, Noyes Data Corporation,

Ridge, NJ, 1974.

Park

57. Slade, 0. H., Ed., Meteorology and Atomic Energy, U. S. Atomic Energy

Commission, Washington 0. C., 1968.

7-4
58. Houston, J. R., et al., DACRIN - A Computer Program for

Calculating Organ Dose from Acute or Chronic Radionuclide Inhalation,

BNWL-B-389, Pacific Northwest Laboratories, Richland, WA, 1974.

59. Rundo, J., et al., "Ingestion of Am-241 Sources Intended for Domestic Smoke

Detectors: Report of a Case," Health Phys. 33, 6, December 1977.

60. Haycock, S. J., "Phenylene Oxide-Based Resins," in

Modern Plastics Encyclopedia, Vol. 49 #10A, 1972-1973.

61. Male, J., General Electric Co., Selkirk, NY, Personal Communication.

62. Alarie, Y. and S. C. Barrow, Toxicity of Plastic Combustion

Products Toxicological Methodologies to Assess the Relative Hazards

of Thermal Decomposition Products from Polymeric Materials, NBS-GCR-77-85,

National Bureau of Standards, Washington D. C., February 19/7.

63. State Fire Marshals Office, State of California, Sacramento, California,

Personal Communication.

64. Key, M. M., Ed., Occupational Diseases - A Guide to Their Recognition,

DHEW#77-181, Washington D. C., June 1977.

65. Ranney, R. Casady Engineering, Torrance, California, Personal

Communication.

66. Litton, C. D., "A Mathematical Model for Ionization-Type Smoke Detectors and

the Reduced Source Approximation," Fire Tech., 13, 1977.

67. Litton, C. 0., "Optimizing Ionization-Type Smoke Detectors," Fire Tec.,

February 1979. (Advanced copy used.)

68. Litton, C. 0., et al., "A Submicrometer Particle Detector and Size

Analyzer," to be published in Rev. of Sci. Instr.

69. Niemeyer, R. G.. "Containment Integrity of Ra-226 and Am-241 Foils Employed

in Smoke Detectors," Report ORNL, TM-2684 Oak Ridge National Laboratory,

Oak Ridge, TN.

70. Vallario, E. J., "Evaluation of Radiation Emergencies and Accidents," IAEA

Tech Pub. #152, Vienna, 1974.

71. Tyree, P. M., "Prototype Testing and Radiological Safety Evaluation of New

England Nuclear Model NER-007 Nickel-63 Ionization Chamber Smoke Detector

Element," New England Nuclear, North Billerica, MA, December 21, 1978.

72. Contents of Letter Communication between P. E. Phillips (now of Department

of Energy) and D. A. Lucht, Chief, Bureau of Inspection, Division of State

Fire Marshal,-Ohio, August 10, 1972.

73. Bukowski, R. W., et al., "Detector Sensitivity and Siting Requirements for

Dwellings," Indiana Dunes Tests, National Fire Protection Association, NFPA

No. SPP-43, 1975.

7-5
74. Liu, B. Y. H., "Sensitivity of Smoke Detectors to Monodisperse Aerosols,"

Final Report to National Bureau of Standards.

75. Bankston, L. P., et al., "Detailed Measurements of the Physical

Characteristics of Smoke Particulates Generated by Flaming Materials,"

Journal Fire and Flamm. 8, 391, 1977.

76. "Smoke Detectors," Consumer Report, October 1976.

77. Hertzberg, M. - and C. D. Litton, "Multipoint Detection

Combustion with Tube Bundles - Transit-Times, Transmissions

Particulates, and General Applicability," U. S. Department

Bureau of Mines, RI-8171, 1976.

of

of

of

Products of

Submticrometer

the Interior,

78. Hertzberg, M. and C. D. Litton, "Pneumatic Fire Detection with Tube

Bundles, Jr. Fire and Flamm. 9, 199, 1978.

79. Personal Communication, Mr. Yakota, U. S. Representative for Taguchi Gas

Detectors, Costa Mesa, California.

80. Gallagher, E. L., "FEMA: NBS Tests Do Not Reflect Reality," Fire Journal,

March 1977.

81. Cohen, B. L. and I-S. Lee, "A Catalog of Risks," Health Phys.

1979.

36, 707,

82. The International Commission on Radiological

Implications of Commission Recommendations that Doses Be Kept As

Low As Readily Achievable, ICRP Pub. 22, April 1"973.

Protection,

7-6
APPENDIX A

TOXICITY OF RESIDENTIAL FIRES

A.1 PHYSIOLOGICAL EFFECTS OF FIRE AND SMOKE

The single most lethal factor in residential fires is exposure to toxic

gases. In extensive studies of the cause of death of fire victims, autoosy

examinations have identified carbon monoxide poisoning as the major contributor

In more than 50 percent of the victims examined(Al,A2). The degree of toxicity

associated with carbon monoxide poisoning is illustrated in Figure A.1(A3 ). A

study by Phillps(A4 ) can be used as an example of the rate and amount of carbon

monoxide that might be evolved during a smoldering fire. In the study a burning

cigarette was used to start a smoldering fire in a sheet and mattress combination

in a dormatory room. The purpose of the test was to study the response times of

various smoke detectors. As the smoldering fire progressed during the test the

room atmosphere was sampled for carbon monoxide and carbon dioxide levels.

Figure A.2 illustrates the rise in carbon monoxide level as the test progressed.

After a duration of 70 minutes the mattress was still smoldering (no flames), the

carbon monoxide level was 750 ppm, the carbon dioxide level was 6000 ppm, and the

room contained a considerable amount of smoke. In regards to the carbon monoxide

levels found during the tests, it is interesting to note from Figure A.1 that for

even a 70-minute exposure at 0.075 percent carbon monoxide, the symptomatic

response of fire victims would be in the headache range. Of course these ranges

are for a standard person and the age and physical and mental states of the

individual would affect the response.

Along with a buildup of carbon monoxide during a fire there is a

decrease in oxygen, an increase in carbon dioxide and temperature levels, and

development of other gas and smoke particles. All of these can potentially work

synergistically to induce physiological impairment sooner than each would do

singularly. The length of exposure parameter greatly influences the

physiological insults with which the components of a fire challenge the human

body. A five minute' exposure to 0.5 to 1.0 percent carbon monoxide is sufficient

to cause lethality while 15 minutes exposure to 0.3 percent carbon monoxide

A-1
0

z

10 - 1 1 I -

LO

.0- - 1- I - - I 1

3.0-

1.0 • •

OLAPS& 0AND

0.2 - 1

• 03 NAUSEA

.025: ::

.001

1 3 45S 10 20 31040M 1t10 ]0300 JD 1IWIll

EXPOSURE TIME (minl

Figure A.I. Effects of CO on Man as a Function of

Concentration and Time.

A-2
100L•

II.

FV I I I I

0

500 1-

300 -

200 1

5-

0.

0

1001-

50,- 0

30

20 k---

I I I I

10 20 60

Time (min)

80 100

Figure A.2. Carbon Monoxide Production from Smoldering

Fire-Started by Cigarette Burning into

Sheet and Mattress.

A-3
induces physiological impairment. Figure A.3 indicates the minimum escape time

for a healthy, clothed person exposed to extreme temperatures(AS). A time

comparison of exposures that can lead to fatality is illustrated as follows:(Al)

5 Minute Lethal Factors

Temperature - 2000C

CO - 0.5-1.0 percent

02 - 6.0 percent

15 Minute Impairment Factors

Temperature - 125 0C

CO - 0.3 percent

02 - 17.0 percent

There is growing evidence that products of combustion other than carbon

monoxide may be responsible for fire fatalities. The combustion products from

polyurethane can amount to 100 or more different compounds - each of which may be

toxic. From many of the items found in a modern residence, toxic products, such

as hydrochloric acid and hydrogen cyanide, can be liberated. These products can

combine with other aerosols to increase the potential for synergistic effects.

Smoke particles could conceivably contribute to a suffocation problem

of fire victims but the probability of the particles being a major cause of death

would depend upon a number of variables. One important variable for the sleeping

victim is that at a low respiratory rate a higher percentage of the inhaled

particles are deposited on lung surfaces(A6 ). This variability is illustrated in

Figure A.4. Little is actually known of the effect of smoke particles on lung

WA) tissue . Since the size range for smoke particles is quite variable and is

affected by time and distance, the significant criterion for. effective fire

warning is that the detector be as sensitive to aerosols as is possible without

undue amounts of false alarms.

The above information is intended to indicate some of the variables

that must be considered when trying to determine if some form of fire warning

will be capable of saving lives. The major criterion for the reduction of fire

fatalities is that the potential victims be warned early enough during the

developmental phase of a fire such that they can escape before some form of

A-4
300 m I I I I

200

100

50

30FC

2

I201-

10--

I I I I I I I

10 20 30 50 100 200 300 500 1000

Temp aC

Figure A.3. Minimum Escape Time for a Healthy, Clothed Person at

Extreme Temperatures. The Curve is Based on the Minimum

Time of Conscious Activity (Observations) and on the

Increase of the Body Temperature (Calculations).

A-5
-10

Lai

zso

00

~LL.

00

LU

~20

01 , ' I I .0 0.02 0.1 1 .0 10

PARTICLE DIAMETER (MICR04S)

Figure A.4. Deposition of Particles in Respiratory Tract.

A-6
physiological insult Incapacitates them. Detector methods exist which can sound

an alarm based on sensing the various physical parameters of fire. Information

based on field tests of these detector instruments definitely Indicates smoke

alarms are the single most appropriate method for residential

installation(A4 ,ASA 9 ). These detectors can warn building occupants of a fire

long before toxic gas or temperature effects become critical and, thus, they have

the potential of saving lives.

A-7

REFERENCES - APPENDIX A

Al. Terrill, J. B., et al., "Toxic Gases

1978.

from Fires," Sci. 200:1343-1347,

A2 Berl, W. G., and M. Halpin, "Fire Related Fatalities: An Analysis of Their

Demography, Physical Origins, and Medical Causes," in

Fire Standards and Safety, A. F. Robertson, Editor, ASTM Tech Pub 614,

NBS, 1976.

A3. MacEwen, J. D., "Toxicology" in Bioastronautics Data Book, J. F. Parker,

Editor, NASA SP-3006, 1973.

A4. Contents of letter communication between P. E. Phillips

Department of Energy) and D. A. Lucht, Chief, Bureau of

Division of State Fire Marshall, Ohio, August 10, 1972.

(now of the

Inspection,

A5. German Aviation Medicine - World War II,

U. S. Air Force by Shololum International,

Reprinted

Inc., Pelham

1971

Manor,

for the

New York.

A6. White, S.,

Bi omedi cal

et al., Biological Tolerance to Air

Criteria, U.S.AEC, CEX-65.4, October 1965.

Blast and Related

A7. Private communication: Dr. A. Phillips,

Or. I. N. Einhorn, University of Utah.

Harvard Medical School, and

A8. Bukowski, R. W.

Smoke Properties,

and G. W. Mullholland,

NBS Tech Note 973, November

Smoke Detector Design and

1978,

A9. Bukowski, R. W., et al, Detector Sensitivity and Siting Requirements

for Dwellings, "Indiana Dunes Tests," NBS Center for Fire Research, NFPA

N.'SPP-43, 1915.

A1O. Assessment of the Potential Impact of Fire Protection Systems

on Actual Fire Incidents, U. S. Department of Commerce, NFPCA

#76045, October 19/8.

Grant

A-9

APPENDIX B

DOSE CALCULATIONAL METHODS

B.1 EXTERNAL DOSE

The external radiation hazard from Am-241 is primarily due to the

presence of the 0.0596 MeV gamma rays emitted in 36 percent of all

disintegrations. Also present in the gamma-ray spectrum are numerous neptunium

x-rays. For Am-241 sources in complete ICSD units, these low energy x-rays are

almost completely attenuated by the ionization chamber wall, detector housing, or

other components. The gamma-ray spectrum of a shielded and unshielded source are

illustrated in Figures B.1 and B.2. The attenuation of the x-rays, coupled with

the fact that the escaping x-rays are of low energy and not truly penetrating

radiation, justifies not Including the x-ray component of the gamma-ray spectrum

in the assessment of the total body external radiation dose from Am-241 ICSD's.

The external radiation exposure rate from an unshielded Am-241 source

resulting from the 60 key gamma rays is derived as follows:

I = (6.58x1O_ 5 )(E)(u/p)(0)

Y

where

I = the exposure rate (R/hr) Y

E = the gamma-ray energy (MeV)

u/p = the mass-energy attenuation coefficient (cm2 /g)

- the photon flux (y/cm2-s)

B-i
0~

0.

0.

59.5

DETECTORs

ACTIVE AREA,

SENSITIVE DEPTtis

ENTRANCE WINDOPW

iJ3.9

INTRINSIC GERNANIUM

500 "4,42 10 NM Bt 0.O4"

*1

I

., .'

I.

'1°

.. ~ .*~-*.

\...

~ :A.~/

O•I I.. -. ..

..4

0'l

I I '.

6W.4 6Wd.0 7"MU "A "IA.a 1"I~.0 1&UO I2WU.O 1300.0

CHANNEL

Figure B.]. Gamma-Ray Spectrum of an Unshielded Am-241 Source ShoWing Multiple

X-Ray Peaks (Energy Values in keV).
a.)

DETECTORs

ACTIVE AREAs

SENSITIVE DEPTHa

ENTRANCE WINDOWs

INTRINSIC GERMANIUM

500 M.*2

10 "M

SE 0.0111

59.5 KEV

A%.* : ;0 . Z* ** t.%

a.

F'

.5

0,4

,,,.-

0.

e..i

If 14I.9 A-0 11 VP.a 5'0 %,!I.a on'5. 4 (

CHANNEL

011.0 9flU P01.0 lim.0 IXA)ft- IVNI a

Figure B.2. Gaima-Ray Spectrum of ICSD Containing 3 pCi Am-241 Source.
The constant (6.58x10"5 ) is the result of unit conversions from ergs to MeV,

seconds to hours, and ergs per gram to roentgens, and has units of

(R-s-g/MeV-hr). For a 1 uCi source, the exposure rate at a distance of one meter

is

I = (6.58x10-5 R-s-g/MeV-hr)(O.06 MeV/y)(0.0292 cmr2 /gm)(0.1 y/cm2 -s)

= 1.2x10- 8 R/hr

Since ICSD's are available in a wide variety of shapes and compositions

and are not symmetrical regarding the amount of attenuating construction material

surrounding the source, it is not possible to accurately calculate the exposure

rates at various distances from ICSD's. There is enough uniformity of design

among the most popular models, however, to reasonably estimate these values.

Also, measured exposure rates from various models have been reported in license

applications and other literature. Peterson(81) reported measured values as high

as 0.29 uR/hr at a distance of 25 cm from an unassembled (without plastic

housing) detector containing 5 uCi. Using the inverse square law, the calculated

dose rate at one meter would be 1.8x10- 2 uR/hr for a detector containing 5 uCi.

On a per unit basis this corresponds to a value of 3.6x10- 3 uR/hr-uCi at one

meter. Graham(B2 ) reported measured dose rates as high as 19 urem/hr at 30 cm

from an industrial type ICSD containing 80 uCi of Am-241. This higher than

expected value is explained by the inclusion of the x-ray component of the

exposure rate, a practice which is not appropriate for total body dose

calculations as discussed previously. General Electric Company B3) has reported

measured exposure rates of up to 0.123 uR/hr at 25 cm from a detector containing

3 uCi. This corresponds to a value of 2.6x10"3 uR/hr-uCi at one meter.

Measurements taken in other directions yielded readings from 5 to 75 percent

lower.

The measured exposure rates reported by Peterson and by General

Electric Company are of special interest since the type of detectors used account

for a large fraction of the total distribution to date. Since the maximum values

reported in their tests are significantly lower (due to detector attentuation)

than the calculated exposure rates for an unshielded source, an added measure of

B-4
conservatism should be included in the value to be used for external dose

assessment. This will offset any effects due to radiation "streaming" through

attenuation voids, and will prevent underestimating exposure rates from other

model ICSD's for which no measurement data are available. The assessments

performed in this report use a value of 8.OxlO" 3 uR/hr-uCi at one meter from an

intact ICSO, and 1.2x10 2 uR/hr-uCi from an unassembled or uncovered ICSD.

Measurements and calculational estimates have also been reported for

various configurations of packaged smoke detectors(Bl B2) Results of these

analyses are presented in sections as they pertain to particular situations under

discussion.

The basic equation used for estimating the total body dose rate from

penetrating radiation emanating from an Am-241 point source is:

Dext = rAnNk

where

Dext m the dose rate (urem/hr)

r = the exposure rate at one meter from 4n Am-241

source within an'ICSD .(8.0x103- uR-m'/hr-uCi)

A - the average Am-241 activity per detector (uCi)

n - the number of ICSO's

N = the number of exposed individuals

d = the source-to-subject distance (meter)

k = a constant relating the dose rate in tissue

to exposure rate in air (urem/uR)

The constant k is derived as follows:

k = 0.869 o

B-5
where 0.869 is the fraction of a urad (or urem) absorbed in air per uR of

exposure, and s is the ratio of the mass-energy absorption coefficients of tissue

to air. For 60 keV photons, the value of $ is

(0.0312 cm2/g) = 1.07

(0.0292 cm2 /g) and

k = (0.869 urem/uR)(1.07) = 0.93 urem/uR.

The dose calculated in this manner represents the amount of energy

absorbed by one gram of exposed tissue-equivalent material, and is substantially

greater than the "effective somatic dose" due to the attenuation which occurs

between the skin and the sensitive organs during whole body irradiation.

O'Brien(B4 ) has applied three-dimensional approximations of organ and tissue

gamma-ray doses in reference male and female phantoms to the organ weighting

factors proposed by Jacobi(BS). For 50 keV photons, O'Brien calculated an

effective somatic dose of 0.501 rem/R for males and 0.562 rem/R for females.

Although doses arrived at in this manner more accurately reflect the concept of

"whole body dose," these refinements are not eTloyed in the radiological

assessments performed in this report since general agreement does not exist

regarding values for the organ weighting factors.

The dose to a specific organ (Dij) from external (photon) sources of

energy j is estimated by

DIj 2 Dext kij

where kij is the effective organ dose conversion factor (rem/R) for organ i and

photon energy j. The factors used here (except for total body) are interpolated

from the data of O'Brien and Sanna(B6). Values for 60 keV photons are given in

Table B.1.
Table B.1. Organ Dose Conversion Factors for

External 60 KeV Photon Source.

Organ k (rem/R)

Liver 0.4

Bone 0.5

Lungs 0.5

Ovaries 0.3

Testes 0.6

B-7
B.2 INTERNAL DOSE

Doses to the total body and to specific organs as a result of

radionuclide inhalation were calculated using the DACRIN computer code(8 7 ) which

is based on the ICRP model for lung dynamics(BSB9). Fifty-year dose commitment

values were calculated assuming a mass median aerodynamic diameter of one micron

for the inhaled particles. Values for dose conversion factors (DCF), which

relate dose commitments for specific organs to the amount of inhaled

radioactivity, are listed in Table B.2. A schematic diagram of the DACRIN

metabolic model is given in Figure B.3. Values of the clearance parameters are

listed in Table 8.3.

Ingestion doses were calculated using the 50-year dose conversion

factors generated by the INREM computer code(BIO). These factors relate dose

commitments for specific organs per unit of ingested activity and are given in

Table B.4.

B-8
Table B.2. Fifty-year Dose Conversion Factors for

Inhalation of Ni-63, Ra-226 and Am-241.B7

IDose Conversion Factors (rem/uCi)a

Radionuclide Total Body Liver Skeleton Lungs

NI-63 3.8E-3 8.2E-3 1.2E-1 1.1E-2

Ra-226 1.OE+2 2.4E-3b 2.7E+2 l.OE+2

Am-241 2.4E+1 3.2E+2 3.3E+2 5.2E+2

a. Assumes particle size of 1 micron and solubility

class W for Ni-63 and Ra-226 and Y for Am-241.

b. From Reference Bl.

B-9
Figure B.3. Schematic Diagram of DACRIN Metabolic Model

Table 8.3. Values of the Clearance Parameters

for the Task Group Lung Model.

SOLUSILITY CLASS

.OMARTIENT a

k~)Tcb (c)

-

Tkc ftk

NP

TS

a

b

c

d

a

f

g.

h

0.01 O.S 0.01 0.1

0.01 0.5 0.40 0.9

0.01 0.95 0.01 0.5

0.2 0.05 0.2 0.5

Y

Tk fk

0.01 0.01

0.4 0.99

0.01 0.01

0.2 0.99

P 0.5

n.a. nt~a

0.5

0.8

n.a.

n.a.

0.2

50

1

50

50

0.15

0.4

0.4

0.05

500

1

500

500

0.05

0.4

0.4

0.15

L 1 O.S I so 1 1000 0.9

(a) Metabolic pathways from lung.

(b) Removal half time in days from compartment via pathway k.

(c) Fraction removed from compartment via pathway k.

B-1O
Table B.4. Fifty-year Dose Conversion Factors for

Ingestion of Ni-63, Ra-226 and Am-241.BlO

Dose Conversion Factors (rem/lCi)

Radionuclide Total Body Liver Skeleton Kidneys

Ni-63 4.30E-3 8.91E-3 1.35E-1 No data

Ra-226 3.1IE+l 2. 3 9E-3a 3.02E+02 6 .77 E-2 a

Am-241 5.42E-2 2.85E-1 8.21E-1 4.07E-1

a. From Reference Blil.

B-11

REFERENCES - APPENDIX B

B1. Peterson, J. R., "Stacking Test for External Exposure,"

Electronics, Aurora, Ill., amended May 19, 1978.

performed for BRK

B2. Graham, C. L., Detectors," Fire

Journal, July,

"Radiation Dose Rates from Various Smoke

1978.

B3. General Electric

Distribution of GE

1974.

Company, "Application for Specific License Authorizing

Model 8201 and 8202 Smoke Detectors," December 18,

84. O'Brien,

Whole-Body

K., "Fluence- and Exposure-to-Dose Conversion

Gamma Irradiation," Health Phys. 35, 494, 1978.

for Human

85. Jacobi, W., "The Concept of the Effective Dose - A

Combination of Organ Doses," Radiat. Environ. Biophys.

Proposal for

12, 101, 1975.

the

86. O'Brien, K., and R. Sanna, "The Distribution of

Humans for Exposure to Environmental Gamma Rays,"

1976.

Absorbed Dose

Health Phys.

Rates in

30, 71,

87. Houston, J. R., et al., "DACRIN - A Computer Program

Dose from Acute or Chronic Radionuclide Inhalation,"

Northwest Laboratories, october, 1975.

for Calculating Organ

BNWL-B-389, Paci fic

B8. International Commission

Dynamics for Committee II

Protection," Health Phys.

on Radiological Protection, "Task

of the International Commission on

12, 173, 1966.

Group on Lung

Radiological

B9. International Commission on Radiological

The Metabolism of Compounds of Plutonium and Other Actinides,

Publication 19, Pergamon Press, Oxford, 1972.

Protection,

ICRP

810. Killough, G. G., et. al., "INREM - A FORTRAN Code which Implements ICRP 2

Models of Internal Radiation Dose to Man," ORNL-5003, Oak Ridge National

Laboratory, 1975.

B-13
B11. Hoenes, G. R., and J. K. Soldat, "Age-Specific Radiation Dose Commitment

Factors for a One-Year Chronic Intake." NUREG-0172, Pacific Northwest

Laboratories, 1977.

B-14
APPENDIX C

RADIOLOGICAL HEALTH EFFECTS

C.1 INTRODUCTION

The estimation of serious health effect risks resulting from internal

exposure to americium is made difficult by the lack of specific human data

relating effects with exposures. This fact also applies to the effects resulting

from prolonged exposure to low levels of lightly-ionizing external radiation

fields such as those produced by Am-241. The purpose of this appendix is to

briefly summarize the state of knowledge regarding internal and external

radiation effects. This knowledge provides the basis used to estimate the

radiological health impact, in terms of cancer mortality and serious genetic

diseases, which would result from the reference cases of ICSD use and disposal

assessed in the main text of this document.

C.2 CARCINOGENESIS

Much literature in recent years has concerned itself with estimating

the extent of cancer incidence and mortality resulting from low levels of

ionizing radiation. These studies have drawn primarily from observations of

carcinogenic effects following human exposure to comparatively high levels of

radiation which were delivered at high dose rates. The externally. exposed

population groups which are the most widely studied are the atomic bomb survivors

of Hiroshima and Nagasaki, a group of British patients who were treated by spinal

irradiation for ankylosing spondylitis, and a group of Israeli children who

received radiation for treatment of thyroid disorders. Two groups of people that

have been subjected to relatively large amounts of internal contamination are

uranium miners and a population of women who used radium paint irr making luminous

timepieces.

Excessive cancer.death rates observed in externally exposed populations

are primarily due to leukemia and cancers of the - breast, lung and

gastrointestinal tract, a pattern which follows fairly closely the estimated(Cl)

C-1
Table C.I. Spontaneous Cancer Mortality Rates

For the United States.

Mortality

Cancer Type (Per 106 Persons Per Year)

Leukemia 71

Lung, trachea, bronchi 379

Stomach 67

Rest of GI tract 264

Pancreas 91

Breast 152

Bone 9

Thyroid 5

All others 666

Total 1704

C-2
-normally-occurring cancer mortality rates (Table C.1). It should be emphasized,

however, that the increased mortality was observed at doses and dose rates which

are many orders of magnitude greater than those encountered in this report.

Thus, the estimation of risk at very low total doses and dose rates must be

extrapolated on the basis of a linear, non-threshold relationship, a practice

which has been seriously questioned by some organizations. For example, the

National Council on Radiation Protection and Measurements (NCRP) has commented

that:

"The NCRP continues to hold the view that risk

estimates for radiogenic cancers at low doses and

low dose rates derived on the basis of linear

(proportional) extrapolation from the rising

portions of the dose-incidence curves at high doses

and dose rates ... cannot be expected to provide

realistic estimates of the actual risks from low

level, low-LET radiations, and have such a high

probability of overestimating the actual risk as to

be of only marginal value, if any, jep&purposes of

realistic risk-benefit evaluation."

More recently, a "Dissenting Report" of the National Academy of

Sciences Subcommittee on Somatic Effects(C3 ) concluded that for low-LET radiation

at doses of between a few and about 100 rad the dose-effect relation for total

carcinogenic effect is very unlikely to be linear in this range. The dissenting

group went on to say:

"We conclude furthermore that risk estimates for

whole body irradiation that are based on individual

organ risk estimation in BEIR-I11 are overestimates

of incidence at low doses. We do not believe that

there is adequate information to determine

accurately the magnitude of the error. It seems

likely, however, that it is as much as an order of

magnitude and possibly more."

While the controversy regarding the estimation of effects of exposure

to low levels of lightly-ionizing radiation is not likely to be settled in the

near future, the currently practiced policy of most responsible organizations is

to extrapolate risk estimates derived at high dose and dose rates to lower. levels

of exposure, adding the proper caveats. This is done in the belief that it is

C-3
more prudent to overestimate the risk than to underestimate it. Table C.2

summarizes the coefficients of risk for whole body irradiation estimated by

various responsible organizations.

There seems to be more general agreement regarding the acceptance of

linear dose-effect relationship for high-LET radiation, such as that produced by

alpha irradiation of internal organs from inhaled or ingested actinides. Lack of

specific human data makes the task of estimating cancer mortality from inhaled or

ingested alpha-emitting radionuclides difficult except for the case of radium

ingestion. Estimates made in this study for internal deposition of Am-241 are

therefore highly uncertain. Table C.3 summarizes the currently available risk

factors which can be applied to internal exposure to alpha-emitting"

radionucl ides.

C.3 GENETIC EFFECTS

Genetic effects occur as a result of changes or alterations of the

genetic material in germ cells. They may result from exposure to a variety of

environmental factors including heat, ionizing and nonionizing radiation, and

numerous chemicals. These genetic alterations can arise from changes within one

or more of the purine or pyrimidine bases comprising the gene or from changes in

the number or structure of chromosomes.

Genetic effects can be induced by exposure of the testes and ovaries to

either external radiation fields or to internally deposited radionuclides.

Ingestion or inhalation of transuranics, for example, may result in the

translocation of transuranics to the gonads. Once deposited in these organs, the

radionuclides can cause a significant dose to sensitive stem cells. Tests

involving plutonium deposition in various animal species have shown, however,

that the total deposition of inhaled pl utonium in the gonads is low enough such

that even allowing for preferential exposure of stem cells, the dose to these

cells would not be expected to exceed the total body average(ClltC12 ). it is

likely that the same can be said for americium.

One conventional approach to assess the genetic health impact of

ionizing radiation is to arrive at a "doubling dose,* which is an estimate of the

radiation dose that results in a twofold increase in the spontaneous mutation

rate. Given .the doubling dose, which is arrived at on the basis of experimental

evidence, and assuming that the burden of human ill health attributable to

C-4
Table C.2. Comparison of Health Risk Estimates (Tumor Deaths or

Gegetic Defects) Associated with Collective Dose of

100 Organ-remn.

SEIBRIC4 UNSCEATF5 ICRPC6 NRCP

Leukemia 20 20 20 28.4

(red marrow)

Breast 450 50 25 25.6,

Lung 16 -10 0 b 2S-50 20 22.2

Bone 2 -17 b 2-5 S N$S

Liver 1 -7b 10-15 NS NS

Thyroidd 1 .6-9. 3 d 10e 5e 4.3f

G6 Tractg 30 10-15 NS 13.6

All Fatal 5 0 -7 8 bh 100 100 121.6

Cancers 9 2 -16 5b ,i

Genetic SOS ,k 20-30" 1000 95-165p

Defects 10-100" ISO

a. Derived from observed incidence in females by correcting for 50%

cure rate and inclusion of males in population.

b. Lower value represents absolute risk model with 30 year plateau

following latent period; higher value represents relative risk

mode-l with lifetime plateau.

c. KS-Not specified

d. Values represent incidence of thyroid cancers per year per 106

person-rem in irradiated children. The risk for adults is somewhat lower.

e. Mortality risk for general population.

f. Incidence of thyroid cancers per year per 106 person-rem in

irradiated children and adults.

g. Includes stomach.

h. Based on atomic bomb survivor data.

$. Based on ankylosing spondylitis patient data.

J. Lower value assumes doubling dose of 200 rem, higher valve

assumes doubling dose of 20 rem.

k. Specific genetic defects including dominant, recessive and

chromosomal diseases.

1. Defects with complex etiology Including congenital anomalies,

anomalies expressed later, constitutional and degenerative

diseases.

m. Seriously affected cases per million liveborn.

n. Total detrimental genetic effects over all generations.

o. Serious hereditary Ill health within the first two generations.

p. Total genetic disorders (autosomal dominant, multifactoral,

chromosomal aberrations and spontaneous abortions) over all

generations.

C-5
Table C.3. Comparison of Health Risk Estimates (Tumor Deaths or Genetic 6

Effects) Associated with Internally-delivered Organ Dose of 10 Rem.

BEIR-IC4 UNSCEARC5 ICRpC6 CC MRC C8 C9 Newcombe CIO

Lung Tumors 16 - 100a 25 - 5Q 20 22 25 20 NSb

Bone Tumors 2 - 17 a d - 5 5 7 5 4 NS

Liver Tumors I - 7a 10- 15 NS NS 20 10 NS

Genetic Defects 50 - 500c 20 - 30 e 1009 95 - 165h NS NS 10

10 - 10 00d 155 f

Notes:

a) Lower value represents absolute risk model with 30 year plateau; higher value represents relative

risk model with lifetime plateau.

b) NS - Not Specified

c) Specific genetic defects including dominant, recessive and chromosomal diseases.

d) Defects with complex etiology Including congenital anomalies, anomalies expressed later, constitutional and degenerative diseases.

e) Seriously affected cases per million liveborn.

f) Total detrimental genetic effects over all generations.

9) Serious hereditary ill health within the first 2 generations; additional damage to later

generations would be of same magnitude.

h) Total genetic disorders (autosomal dominant, multifactoral, chromosomal observations and spontaneous abortions) over all generations.
normally occurring mutations is known (and is the same for radiation-induced

mutations), one can directly estimate the detrimental genetic effects for any

specific radiation dose. The 1977 UNSCEAR Report reviews and discusses the state

of knowledge on this topic and arrives at a doubling dose of 100 rem, while the

BEIR-III report ascribes to a range of 50 to 250 rem.

C.4 HEALTH EFFECT RISK COEFFICIENTS

The coefficients of risk used for the purposes of estimating cancer

mortality and genetic detriment are listed in Table C.4. These risk estimates

are based on the best currently available literature values (as shown in previous

tables) and are generally considered to be upper level estimates. Thus, although

a lower level of risk - or even zero risk - cannot be entirely ruled out on the

basis of currently available data, the use of upper level estimates based on the

linear, non-threshold hypothesis is considered to represent the most prudent

approach to the low level risk assessment performed in this report.

C-7
Table C.4. Health Effect Risk Estimates

Used in this Report.

Tumor Deaths or Sgrious Genetic

Cancer Defects Per 100 Organ-Rem

Liver 15

Bone 5

Lung 25

All Other Fatal

Cancersa 100

Total 150

Genetic Defects 200

a. Primarily leukemia and cancers of the breast,

GI tract and thyroid.

C-8
REFERENCES - APPENDIX C

C1. American Cancer Society, '75 Cancer Facts and Figures, New York, 1974.

C2. National Council on Radiation Protection and Measurements,

Review of the Current State of Radiation Protection Philosophy, NCRP Report

No. 43, Washington, D. C., 1975.

C3. National

The Effects

Academy of Sciences,

on Populations of Exposure to

National

Low Levels

Research Council,

of Ionizing Radiations

(BELR ILL), Washington, U. C., 19/9.

National Academy of Sciences, National Research Council,

The Effects on Populations of Exposure to Low Levels of Ionizing Radiations

(BEIR 1), Washington, D. C., 1972.

C4.

CS. United Nations Scientific Committee on the Effects of Atomic Radiation

(UNSCEAR), Sources and Effects of Ionizing Radiation, 1977 Report to the

General Assembly, with annexes, United Nations, New York, 1977.

C6. International Commission on Radiological Protection,

Recommendations of the International Commission on Radiological Protection,

ICRP 26, Pergamon Press, Oxford, 1977.

C7. Nuclear Regulatory

Consequences", Appendix

D. C., 1975.

Commission, "Calculation

VI to Reactor Safety Study,

of Reactot

WASH-1400,

r Accident

Washington,

C8. Medical Research

Stationery Office,

Council,

London, 1975.

The Toxicity of Plutonium, Her Majesty's

C9. Mays, C. W., "Estimated Risk from Pu-239 to Human Bone, Liver

Biological and Environmental Effects of Low-Level Radiation,

International Atomic Energy Agency, Vienna, 1976.

and Lung,"

Vol.

in

II,

in C1O. Newcombe, H. B., "Mutation and the Amount of Human Ill Health,"

Radiation Research: Biomedical, Chemical and Physical Perspectives,

0. F. Nygaard, et. al., eds., Academic Press, New York, 1975.

C-9
Cl. Thompson, R. C., and W. J. Bair, "Health Effects from Transuranic Exposure," in Rocky Flats Plant Site Draft Environmental Vol. 2, September, 1977. Impact Statement, ERDA-1545-D,

C12. Richmond, C. R., and.R. L. Thomas, "Plutonium and other Actinide Elements in Gonadal Tissues of Man and Animals," Health Phys. 29, 241, 1975.

C-10
%PC FRM 335 U.S. NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER A4ssigned by DDC)

(7.771 NUREG/CR- l 156

BIBLIOGRAPHIC DATA SHEET

4. TITLE AND SUBTITLE ("€d Volume No., if appropriate) 2. (Leave blank)

Environmental Assessment of Ionization Chamber Smoke

Detectors Containing Am-241 3. RECIPIENT'S ACCESSION NO.

7. AUTHORIS| 5. DATE REPORT COMPLETED

R. Belanger, D.W. Buckley, J.B. Swenson MONTH IYEAR

• "October 1979

9. PERFORMING ORGANIZATION NAME AND MAILING ADDRESS (Include Zip Code) DATE REPORT ISSUED

Science Applications, Inc., MONTH, IYEAR

1200 Prospect Street November 1979

La Jolla, California 92038 6. (Leave blank)

8. (Leave blank)

12. SPONSORING ORGANIZATION NAME AND MAILING ADDRESS (Include Zip Code) 10. PROJECT/TASK/WORK UNIT NO.

U.S. Nuclear Regulatory Caomission

Material Certification and Procedures Branch 11. CONTRACT NO.

Division of Fuel Cycle and Material Safety, NMSS NRC-02-78-045

Washington, D.C. 20555

13. TYPE OF REPORT PERIOD COVE RED finclusive dates)

Technical Report January, 1979 through October, 1979

15. SUPPLEMENTARY NOTES 14. (Leave blank)

16. ABSTRACT #200 words or less]

The NRC is reevaluating the adequacy of existing policy dealing

of consumer products containing radioactive material. One such

ionization chamber smoke detector (ICSD), which in recent years

distributed.

with the distribution

consumer product is the

has become widely

This report is the assessment of the impact of ICSD's c people and the environment. Its

benefits and risks are evaluated for presently-distribLted ICSD's against alternatives.

The work is intended to:be a source of information for a generic environmental impact

statement (GELS) on consumer products containing radioactive material which will be

written in the future.

The report concludes that the sum of doses to the population from the annual production,

distribution, use, and disposal of 14 million Am-241 ICSD's is much lower than that

which could potentially result in one cancer death. The use of Am-241 ICSD's is

justifiable as a means to prevent loss of-life and property. The estimated benefit-torisk ratio is more than 15.,000.

17. KEY WORDS AND DOCUMENT ANALYSIS 17a. DESCRIPTORS

17b. IDENTIFIERS/OPEN-ENDEO TERMS

18. AVAILABILITY STATEMENT 19. SECURITY CLASS (This report) 21. N F PAGES

Unclassified

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