NAT'L INST. OF STAND & TECH

A 1 1 1 b 3 T 7 5 b

NBSIR 81-2441

National Measu

Office of Measurements for

Nuclear Technology

Annual Report 1981

Laboratory

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Measurement Laboratory

Washington, DC 20234

January 1 982

Annual Report, Fiscal Year 1981

(October 1, 1980 - September 30, 1981)

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U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

NBSIR 81-2441

NATIONAL MEASUREMENT LABORATORY

OFFICE OF MEASUREMENTS FOR

NUCLEAR TECHNOLOGY

ANNUAL REPORT 1981

John D. Hoffman

Director

National Measurement Laboratory

H. Thomas Yolken

W. P. Reed

Chief, Office of Measurements

for Nuclear Technology

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Measurement Laboratory

Washington, DC 20234

January 1982

Annual Report, Fiscal Year 1981

(October 1, 1980 - September 30, 1981)

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

Preface

This annual report is a summary of the National Bureau of Standards

(NBS) Measurements for Nuclear Technology (MNT) Program for Fiscal Year

1981. The MNT activities at NBS are divided into two programs: Nuclear

Safeguards and Nuclear Waste Management. The Nuclear Safeguards Program

was the first to be initiated near the end of Fiscal Year 1977, while the

Nuclear Waste Management Program was initiated near the end of Fiscal

Year 1980. However, NBS did make significant contributions to the nuclear

safeguards field in years past. For example, in the 1950's, C. J. Rodden

and other NBS scientists founded a laboratory for the measurement of

nuclear fuels at NBS. This laboratory was later transferred to the U.S.

Atomic Energy Commission and became known as the New Brunswick Laboratory.

In addition, work by W. Shields and co-workers in the 1960's established

NBS as a world leader in the development of ultra-high accuracy mass spectrometry for chemical and isotopic assay of nuclear fuels. NBS

Standard Reference Materials for the chemical and isotopic assay of

uranium and plutonium provide the foundation for nuclear safeguards

measurements throughout the world.

The Department of Energy (DOE) in late August 1979 invited the

National Bureau of Standards to consider the establishment of an appropriate technical assistance program to meet the measurement standards

needs of the waste disposal problem.

NBS assembled a study group consisting of 13 experts in a variety of

scientific and engineering disciplines. The group was asked by NBS

management to study the problem, to explore critical questions, and to

define an appropriate NBS technical program in a final report to be

completed and reviewed by March 31, 1980. The report was completed on March 31, 1980, and submitted to DOE. The goal of the NBS program stated

in the report was to provide a measurement base (including reference

methods, Standard Reference Materials, Standard Reference Data, measure- ment assurance procedures, and scientific laws and concepts of waste

behavior) to allow other organizations to (a) measure short-term behavior,

(b) predict long-term behavior (c) choose acceptable disposal systems,

and (d) provide quality control of processing and assembly in nuclear

waste management. The NBS Nuclear Waste Management Program was initiated

in September 1980 and was completely supported by DOE funds.

Because of a number of decisions in the Federal Government, with

regard to the direction of the programs and availability of financial

resources, both programs were terminated at the end of this fiscal year

(September 30, 1981).

In the case of the nuclear safeguards program, the termination

resulted in an orderly turnover of responsibilities and the phase out of

operations. For the Nuclear Waste Management Program, the decision not

to fund the program was made in the fourth quarter of the first fiscal

year of the program. As a result, a number of tasks did not reach a natural stopping point. Thus, this annual report for the Nuclear Waste

Management Program will contain a number of fragmented technical reports.
It is hoped that if sufficient technical content becomes available during

Fiscal Year 82, individual authors will publish them either in the open

literature or as NBSIR's. Should the financial situation change it is

entirely possible that many of the technical activities would be reinitiated.

We hope that this annual report will provide the technical community

with a view of the Program's direction. We encourage members of the

community to make recommendations to us concerning the needs and future

direction of individual research efforts presented here.

We wish to acknowledge the help and support of Dr. B. Stephen Carpenter

who managed the Nuclear Safeguards Program through the first half of

Fiscal Year 1981. His planning and guidance helped make this program

successful

.

William P. Reed

H. Thomas Yolken

Office of Measurements for

Nuclear Technology
TABLE OF CONTENTS

Page

Preface I

I. Introduction ]

II. Personnel 4

III. Measurements for Nuclear Safeguards Program - A Technical

Overview 7

A. Nondestructive Assay 7

B. Destructive Analytical Chemistry -jg

C. Bulk Measurements 29

D. Applied Mathematics 35

IV. Measurements for Nuclear Waste Management Program - A

Technical Overview ... 33

A. Waste Forms - Leachability Mechanisms .... 33

B. Waste Forms - Research, Reference Materials Data and

Measurement Methods 54

C. Containers, Backfill, and Mathematical Support .... 37

V. Appendix

A. Major Consulting and Advisory Services 73

B. Committee Workshop Participation 77

C. Publications 1980 to 1981 7 g

D. Talks 1980 to 1981 81

E. Organized Symposia and Workshops 33

F. Functional Statements 34

G. NML Organization! Chart 35

H. NBS Organizational Chart 33

I. Budget, Office of Measurements for Nuclear Technology . 37

I. INTRODUCTION

The Office of Measurements for Nuclear Technology (OMNT) was established to provide national measurement standards needed to safeguard

nuclear materials. In addition, during the past year, a program in

nuclear waste management was established. Thus, the OMNT for FY 81

consists of two separate activities, Nuclear Safeguards and Nuclear

Waste.

A. Nuclear Safeguards

1. Introduction

Rapid and sensitive methods to detect the diversion of nuclear

materials are an essential objective of the measurements for nuclear

technology program. This objective can be achieved with the aid of accu- rate and precise methods of measurement of nuclear materials at all

phases of manufacture, use, and transfer to maintain material accounting.

Effective and universal measurement standards are required to attain the

necessary accuracy of measurement.

The NBS program for nuclear safeguards serves three sets of

clients: the Nuclear Regulatory Commission (NRC) and the U.S. commercial

nuclear industry; the Department of Energy (DOE) (as developer of nuclear

safeguards technology and as regulator of nuclear facilities operated for

DOE) and U.S. Government-owned DOE nuclear facilities; and the International Atomic Energy Agency (IAEA) and countries that have nuclear

facilities under the jurisdiction of the Non-Proliferation Treaty. The

FY 1981 NBS Nuclear Safeguards Program was funded by DOE and the Department of State (DOS).

2. Goals and Objectives

The goals and objectives of the NBS program are derived from

the perceived needs of the sponsoring agencies—to reduce the risk to the

public from the illegal diversion of nuclear materials by providing a common and accurate standardization basis for measurement of nuclear

fuels. This goal is to be achieved for all of the measurements that need

to be made throughout the fuel cycle on a wide variety of material forms.

In order to meet this goal, our objectives are to provide measurement

standards and services for the four major measurement areas for nuclear

safeguards accountability.

3. Tasks

To achieve these goals and objectives, three task areas are utilized that combine similar technological resources of NBS. These

three task areas are:

a. Bulk and Nondestructive Measurements for Nuclear

Safeguards

1
b. Chemical Measurements for Nuclear Safeguards

c. Systems Studies and Statistical Analysis

B. Nuclear Waste Management

1. Introduction

In August 1979, DOE invited NBS to consider establishment of a technical program that would contribute to the measurement standards

foundation required for disposal of nuclear waste. A group of NBS scientists was asked by the management of NBS to examine the needs for measure- ment standards in nuclear waste management and, if desirable, to recommend

a technical program. The NBS study (funded by DOE) was completed, approved

by the NBS Executive Board, and submitted to DOE on March 31, 1980. DOE

staff have reviewed the NBS proposal and have provided $350,000 to NBS to

initiate a portion of the program in FY 1980 (last quarter) and $1,500,000

(later reduced to $1,175,000) to fund the program in FY 1981, with the

intention to increase the funding in future years, to allow additional

activities to be included in the program. NBS and DOE consummated a Memorandum of Understanding in the nuclear waste management area in

February 1981.

2. Goals and Objectives

The summary of the NBS report on nuclear waste management follows

". . . The National Bureau of Standards proposes to support the national

program in nuclear waste disposal by: assisting in the development of

measurement techniques and standards to assess stability, providing

knowledge of factors controlling stability of the waste package, determination and evaluation of data critically needed for evaluation of

alternative waste forms and packages, and development of measurement

standards and procedures needed for quality control. This is an appropriate role for NBS for several reasons. First, accuracy is required in

difficult measurements that are essential to the solution of a national

problem. Second, competence in similar measurements on other materials

already exists at NBS. Third, credibility of results is extremely important; the traditional NBS measurement and standards role of third party

objectivity with no promotional or regulatory interest is appropriate.

Fourth, certain voluntary consensus standards are needed, as well as regulatory standards; the existing extensive work of NBS in support of

the voluntary consensus standards system makes a good base for similar

standards work in support of nuclear waste disposal."

The strategy of the NBS program recognizes the need to disseminate

existing NBS capability, mainly in the area of short-term performance,

and to concurrently develop the new scientific basis needed for long-term

prediction, and to provide the additional basis needed for short-term

performance capability. For example, work is needed to improve the

accuracy of existing leach tests and develop consensus on standard tests

to determine short-term performance. This work is critically needed, but

must be supplemented by work on the mechanisms controlling release so

2
that long-term predictions can be made. NBS will accordingly pursue

parallel and interactive efforts centered respectively on reference leach

tests involving chemical analysis and on the kinetics of long-term release.

The NBS strategy also recognizes the importance of collaboration with

work already in progress in a number of government, industry, and university

laboratories. NBS will make optimum use of its existing experimental

facilities in carrying out this work. NBS will concentrate on model

systems using the same chemical compounds and structures, but employing

isotopes with no or relatively low levels of radioactivity. Work on actual, high activity waste forms will be carried out in a cooperative

manner at existing hot cells in other laboratories.

With the foregoing considerations in mind, the overall goal of

the NBS program can be stated as follows: To provide a measurement base

(including methods, data, traceability to basic standards, and assurance

procedures) and scientific laws and concepts of waste behavior to support:

(a) measurement of short-term behavior, (b) prediction of long-term

behavior, (c) choice of acceptable disposal systems, and (d) quality

control of processing and assembly in nuclear waste management.

The NBS program was developed in terms of work needed on each

component of the multi -barrier system and the need to monitor the system.

The following technical themes run through much of the work:

a. the interactions between components of the system,

b. quantitative analysis of elements and phase,

c. stability of phases over relatively short times,

d. leach and corrosion rates over relatively short

times

,

e. mechanisms and quantitative basis of phase changes,

mechanical deterioration, leaching, corrosion,

absorption, and transport,

f. predictive scientific laws and concepts to allow

choice of disposal systems, and

g. test methods and procedures for quality control.

3. Tasks

To achieve these goals and objectives, the NBS program on nuclear waste has developed, for FY 1981, three tasks which combine

similar technology resources of NBS. These three task areas are:

a. Leachability Mechanisms for Waste Forms

3
b. Nuclear Waste Form Reference Materials and Data

c. Containers, Overpack, Corrosion and Backfill

II. PERSONNEL

The Office of Measurements for Nuclear Technology (OMNT) is in the

NBS National Measurement Laboratory (see organizational chart in Appendix).

The OMNT consists of two major programs: Measurements for Nuclear Safeguards

and Nuclear Waste Management. Each program is run by the Team Management

concept, which allows members from different centers or programs within

NBS to help the programs run effectively. The OMNT interacts with four

centers in NML and two centers and the Continuous Process Technology

Program in NEL. The Management Team concept has been demonstrated to be

a fruitful approach to matrix management.

An FY 1981 organizational chart is shown in Appendix G. Tables 1

and 2 provide a summary of the NBS-OMNT personnel.

4
TABLE 1. Summary of NBS personnel involved in the OMNT Safeguards Program.

Technical Area

A. Bulk Measurements

Flow

TankVol. Cal. Algorithm

B. Nondestructive Assay

Half-Life Measurements

Calorimetry

NDA- gamma

Resonance Neutron Radiography

Resonance Neutron Tomography

C. Chemical and Isotopic Measurements

Low enriched U^Og Isotopic

Resin Beads

Davies-Gray U

IDA-80 U and Pu

Moisture in Pu Oxide

4244

Pu Spike SRM

D. Statistics

Measurement Assurance Programs

Reference Materials

Calibrations

In-Plant Error Analysis

E. Safeguards Systems Studies

Pri ncipal Investigators

G. Baumgarten, A. Gaigalas,

B. Robertson, T. Yeh

F. Jones

L. Lucas

D. Ditmars

S. Carpenter

R. Schrack, J. Behrens, R. Johnson

T. Cheng, D. Garrett

L. Machlan, J. Gramlich

J. Fassett, W. Kelly

J . Moody

L. Machlan, J. Fassett, J. Gramlich

F. Jones

J. Fassett, H. Kingston, L. Machlan

H. Ku, J. Lechner, W. Liggett

C. Spiegelman

S. Bologa, M. D. K. Maltese,

J. Schleter

5
TABLE 2. Summary of NBS personnel involved in the GMNT Waste Program.

Technical Area

Waste Forms

(1) Leachability Mechanisms

Concepts - Theory

Radiation Effects

Transport, Thermochemistry, Microstructures

Mechanical Properties

Microfracture

(2) Research & Reference Materials,

Data Measurement Methods

Phase Diagrams of Relevant Ceramics R. Roth, W. Brower, M. Austin,

M. Koob

Leachability Research Materials (Glass) W. Haller, D. Cronin

Pri ncipal Investigators

R. Mountain, R. Munro

T. Cheng, D. Garrett

R. Roth, C. Chiang

S. Wiederhorn

S. Freiman, G. White

Leachability Reference Test Methods

B. Containers, Overpacks, Sleeves

Corrosion Mechanisms

Data and Methods

Feasibility and Long-Term Deep Test

C. Backfill

Mechani sms Research Materials

Data and Test Methods

D. Mathematical Support

Statistical Engineering

Submodel i ng

E. Material Review Board

H. Kingston, G. Lutz, M. Epstein

J. Kruger

B. Anderson

M. Rodriguez, K. Hardman

F. Yokel , R. Chung

L. Solomone

H. Ku

J. Fong

H. Frederikse

6
III. MEASUREMENTS FOR NUCLEAR SAFEGUARDS PROGRAM - A TECHNICAL OVERVIEW

A description of the technical activities in each of the Program's

areas is given in this section. In addition, accomplishments during FY

1981, the fourth year of the Program, are reviewed.

A. Nondestructive Assay

The NBS effort on standards for nondestructive assay (NDA) of nuclear

materials is motivated by the need for reliable, accurate, timely and

economic methods for the measurement of special nuclear materials. A

wide variety of activities are being carried out in NBS laboratories to

fulfill this objective. The activities may be grouped into three major

categories: reference methods, standard reference materials, and data

development and calibration.

1. Reference Methods

Reference methods are methods having demonstrated precision and

accuracy. Due to their complexity, these techniques are generally suited

only for a specially equipped laboratory. These reference measurement

methods are used to characterize reference materials or as references for

developing and calibrating simpler techniques that are inherently less

accurate.

a. Resonance Neutron Radiography

The effort on the resonance neutron tomography project

during last year was devoted to: (1) the construction of the reactor-based

resonance neutron safeguards experimental system and the making of provisions

for its use, and (2) the initial tomographic construction of a nuclear

waste container.

The tomographic reconstruction of a point object using the

filtered back projection technique has been carried out before. In an effort to further study the reconstruction technique as applied to those

actual fuel pellets within a gallon-sized container, a second experiment

was conducted on the BT~7 beam port of the NBSR.

The experiment consisted of three parts: (1) the production

of reference calibrations, (2) the scanning of the waste container by the resonance neutron beam, and (3) the mathematical reconstruction of the

container based on the results of (1) and (2). The reference calibrations

were necessary to interpret the responses of the fission detectors. The

responses were functions of particular neutron beam characteristics,

detector system efficiencies, and the effect of neutron beam softening in

the object to be studied.

U-235 and U-238 reference discs were made from SRM U-970

and U-0002 materials, respectively. The U-235/U-238 reference discs were

then placed in the resonance neutron beam and the transmitted beam recorded

by both U-235 and Pu-239 foils in the NBS double fission detectors.

7
The uranium was available as uranium oxide in a finely

powdered form which had to be encapsulated to form samples of a known

thickness which could then be used for the transmission measurements.

The containers consisted of an outer shell which had a well to contain

the sample and a plug to compress the powder. The plug was 0.002 to

0.003 inch oversize and after loading was pressed into the container

using an arbor press which exerted a force of several tons. The mass of

the specimen was measured with an accuracy of 0.1 milligram.

In order to get other information on the thickness of the

specimen, transmission measurements were made using gamma rays from a Cobalt-60 source. A well collimated beam, 1/4 inch in diameter, was

used, and measurements were made for the lower peak (1.10 to 1.25 meV),

the upper peak (1.25 to 1.40 meV), and the two combined. The average of

the three measurements was used as the value for the gamma ray transmission.

Radiographs were taken of the samples using a 250 kvp

x-ray system. It is apparent from the radiographs that, for some of the

samples, leakage of the powder from the well had occurred and that in

others the distribution of the powder was not uniform. Finally, it is

apparent that the density of the powder varies from sample to sample.

For nine of the samples the radiographs indicate that the data should be

reliable. For these samples the gamma ray transmission values were

fitted by linear regression to the equation

I = I Q

exp(-am

s ), (1)

where m is the mass of a cylinder of U 3 0 8 6.4 mm in diameter. Figures 1

and 2 snow the data used and the fitted line. The self-indication effect

is clearly demonstrated in the case of U-235 detector, while the responses

of Pu-239 detector to both U-235 and U-238 materials are very similar due

to the fact that Pu-239 resonant cross sections do not match the total cross sections of either materials. The equation was then used to calculate

m for the other sample. Three methods were used to calculate the total mass of the samples used for the neutron transmission measurements. They were as follows:

Method I is the one just described—a combination of the

values of m obtained from measurements made on the radiographs and the

known masses of the reliable samples with the values of m for the other

samples calculated from the gamma ray transmission using eq (1).

Method II smooths the data by using eq (1) to calculate

all of the values of m

s from the gamma ray transmission.

Method III was suggested by the fact that when the neutron

transmission is plotted against the design values of the thickness, the

resulting curve appears to be as good as the one obtained from Methods I or II which are based on the gamma ray transmission. Method III, in

effect, assumes that all of the sample is effective in absorbing the

neutrons.

8
Normalized

Fission

Detector

Rate

Figure 1. Normalized U-235 and Pu-239 fission detector rates as a function of SRM U-970 sample thicknesses.

9
Normalized

Fission

Detector

Rate

Figure 2. Normalized U-235 and Pu-239 fission detector rates as a function of SRM U-002 sample thicknesses.

10
As shown in previous reports, a plot of the neutron transmission versus the thickness of the absorber is expected to follow the

equation:

1 = 1 o (a

o + a lx + a2

x2 ^’ ( 2 )

with the expected value of a

Q being 1.

The neutron transmission was measured using a two compartment fission chamber with one foil being U-235 and the other Pu-239. The

absorbers were 97 percent enriched U-235 (NBS SRM U-970) and fully depleted

U-238 (NBS SRM U-0002).

When the data are fitted to eq (2) by a least square

calculation, a is found to be 0.9 for U-235, /U-235 sample detector

combination, a8out 0.95 for U-235, /Pu-239 combination, and about 0.97 for

U-238 with either detector. No reasonable explanation for this is known.

It was decided to set a = 1 in eq (2) and to weight the

data so that larger values of x are given more weight. The 26 data

points were divided into groups of 9, 9, and 8 which were given weights

of 1, 2, and 3, respectively. The results for Methods II and III agree

quite well and are considered to be the best available from the present

data. Table 3 gives the values of a x and a2 obtained by this method for

all four combinations of sample and detector, expressed in cm 1 and cm2

. These are the numbers that would apply if the sample is a solid metal

foi 1

.

The set up for the scanning procedure is shown in figures

3 and 4. The waste container was first moved horizontally with respect

to the neutron beam at 1.6 mm intervals, the total width covered was 6.4

cm. At the end of each horizontal scan, the container was rotated 3°.

Sixty such rotations were acquired for each slice of the container to be

reconstructed. A total count of > 10,000 was recorded for each point

scanned on both U-235 and Pu-239 detectors. Dwell times on each point

varied from 15 s to 25 s.

The preliminary tomographic reconstruction of the slice of

the container that passes through the centers of all three pellets is

shown in figure 5. The heights of the three columns indicate the relative

U-235 contents. The initial results show the isotopic U-235 enrichments

in the three pellets to be 4.35 percent, 2.69 percent, and 1.03 percent

as compared to the known values of 3.96 percent, 2.52 percent, and 1.19

percent, respectively. The errors are mainly introduced by the calibration process. To minimize the errors, one has to use metallic reference

discs instead of the ones made from powder SRM's so the effective thickness of each disc can be measured more accurately.

Y. T. Cheng, D. Garrett, W. Parker, M. Ganoczy, M. Dorsey

11
Absorber

TABLE 3. Calculated values of a^ and a

Absorber

,238

,235

,235 ,238

= 4. 941 cm

-1

a^ = 1. 518 cm

a^ = 9. 534 cm

-2

a^ = 1.467 cm

-2

a^ = 3.776 cm

-1

a^ = 1.440 cm

-1

a

2 = 6. 233 cm

-2

a

2 = 1. 321 cm

-2

12
Figure

Beam Stop7

DetectorTop View

n

- Aperature

Cd, Au, In

Cd Filter

Rotational Drive

\

Neutron Beam

Fuel Pellets

Vertical Motion Drive

Horizontal Motion Drive

3. Top view of the tomography scanning setup.

13
Figure 4. Side view of the tomography scanning setup.
Figure 5 Tomographic construction of U-235 contents in the fuel pellets.

15
b. Other Neutron Measurement Techniques

The development of high resolution two-dimensional position

sensitive neutron detectors has continued. This work has resulted in

successful detectors based on both proportional ionization counting and

scintillators. Resolution has been improved into the submillimeter range

and neutron detection efficiency improved by several orders of magnitude.

Accurate radiography is now possible along with a complete quantitative

assay of small samples (5 cm or less in width). With the improved detector

efficiency it is now possible to consider measurements away from a reactor

or large accelerators usually associated with radiographic methods. The

method is now ready for testing in practical situations such as nondestructive assay of standard samples prepared for nuclear material measurement.

The development of a related new method called Neutron

Resonance Transmission Assay (NRTA) has been pursued. This method uses the neutron resonance structure of the actinides for isotopic identification

and accurate assay and does not require position sensitive detectors.

Measurements are possible with the small radiographic accelerators typically

used for inspection of heavy section steel by adapting them for neutron

production. The method is capable of a complete nondestructive isotopic

assay of intact spent nuclear fuel assemblies. Measurements demonstrate

that nine actinides and four fission products can be measured in about

ten minutes. Optimization accuracies in the 1 percent range may be

expected. Current precisions are shown in table 4 for commercial spent fuel.

Adoption of the method would have a significant impact on safeguards mea- surements related to the storage of spent fuel, the front end of fuel re- processing facilities, and national and international commerce in fresh and

spent nuclear fuel.

C. D. Bowman, J. W. Behrens, R. A. Schrack

c. Calorimetry

The aim of the calorimetric NDA activity is to provide

measurement assurance and traceability to National Standards for calorimetric measurements made in the industrial assay of photoni um-bearing

solids. This is to be achieved through the exchange of calibrated plutonium heat sources between major suppliers and the NBS. Calorimetric

measurements at NBS will be made in a Bunsen ice calorimeter and in an automated twin-bridge heat-flow calorimeter under construction at NBS.

In FY 1981, construction was completed on the thermal

sensing elements for the NBS heat-flow calorimeter. These were installed

in the complete calorimeter body and thermal testing of the unit was

begun. Construction of the automated sample-changing assembly was started.

Four encapsulated plutonium heat sources provided by the

Mound Facility which had previously been measured by NBS were returned to

Mound for radiographic examination. At the same time, Mound will perform

new thermal power measurements and re-certify their predicted power

levels for the next three-year period. The Mound results have been

received, but there has been an extended delay in shipping these sources

due to a requirement that they be moved by special carrier.

16
TABLE 4. Current analysis results for center cut 2.5 cm sample.

Isotope

E o(eV) Atoms/Barn

Current

Precision

Relative

Abundance

234

u 5.19 l.E-5 *

2. E-4

235

u 8.78 (4. 36±0. 15) E-4 3% 9.4E-3

236

u 5.45 l.E-4 * 2.E-3

238

u 6.6 .04651.0004 1% 1.0

238 dPu 18.6 3.E-5 *

6. E-4

239 dPu 10.93 (2.601.11) E-4 4% 5.6E-3

240 dPu 1.05 (1.111.02) E-4 2% 2.4E-3

241 dPu 13.4 8.5E-5 * 1.8E-3

242

f>u 2.67 (1.401.04) E-5 3% 3.0E-4

131

x e 15.0 (3.261.05) E-5 2% 7.0E-4

133JJ

Cs 5.8 8. E-5 * 1.7E-3

241.

Am 1.27 6. E-5 * 1.3E-3

243.

Am 1.36 8.E-6 * 1.7E-4

152,

bm 8.1 (7.271.14) E-6 2% 1.6E-4

145

Nd 4.35 2. E-5 * 4. E-4

"Tc 5.6 * 4. E-4

* Visual fit only, probably good to 10%.

17
In consultation with members of the NBS Statistical Engineering

Division, we have developed a number of guidelines for an NBS Measurement

Assurance Program covering encapsulated plutonium heat sources. They

include annual thermal measurement in each of four power decades (from

0.001 W to 10.0 W) of two different plutonium heat sources in a heat-flow

calorimeter. In addition, one of these sources from each decade should

be checked in the ice calorimeter. The guidelines have been presented to

the Mound Facility for consideration.

D. Ditmars

2. Standard Reference Materials for NDA - U 308 Low Enriched

Gamma- Ray Standards

The isotopic analysis of four of the five low-enriched materials

intended for certification as SRMs for NDA gamma- ray standards has been

completed. These materials were received from the Central Bureau of

Nuclear Measurements (CBNM), Geel , Belgium. The four materials consisted

of U3 08 with 235 U enrichments of 0.31 percent, 0.71 percent, 1.9 percent,

and 2.9 percent.

The goal of the isotopic measurement at NBS was to accurately

determine the level of 235 U enrichment and to demonstrate the degree of

isotopic homogeneity. A sampling scheme to achieve these objectives was designed by the NBS Center for Applied Mathematics and supplied to CBNM

for guidance during the packaging of the NDA samples. As a result of

this sampling scheme, NBS received 13 samples from each enrichment batch.

Of the total, twelve 0.5 gram samples were for isotopic measurements by

thermal ionization mass spectrometry, and one 20 gram sample was for

determining the quantity of 232 U contamination via gamma-ray spectrometry.

After completion of the gamma- ray measurements, the 20 gram samples were shipped to NBL for uranium assay. The gamma-ray spectrometry results

indicated no detectable quantities of 232 U in the samples.

Mass spectrometric measurements of the isotopic composition of

the sample showed that the 235 U homogeneity was better than 0.1 percent

for the 0.7 percent, 1.9 percent, and 2.9 percent enriched material. A

range of slightly greater than 0.1 percent for the 0.3 percent 235 U

material is within the measurement uncertainty of the isotope ratio

measurements and may therefore not reflect any sample inhomogeneity.

In addition to the characterization measurements of the bulk

materials by gamma- ray spectrometry and mass spectrometry, aluminum cans were designed and fabricated to package the material. Very rigorous

specifications were required to produce containers of reproducible dimensions. Calibration experiments to verify that all cans would meet specifications were conducted both at NBS and CBNM.

The final and most enriched standard (4.5 percent 235 U) has

arrived at CNBM and is being packaged. Samples are ready for shipment to

NBS for gamma-ray and mass spectrometric measurements.

B. S. Carpenter, J. W. Gramlich, L. A. Machlan

18
3. Data Development and Calibration

a. Radioactivity Program

A technical article on the results of the NBS measurements

of the half-life of plutonium-240 has been completed and is in the process

of editorial review. It will be published during FY 82 in the International

Journal of Applied Radiation and Isotopes jointly with the results of the

measurements of the other members of the DOE Half-Life Evaluation Committee.

A copy of the abstract is shown in figure 6.

In anticipation that x- and gamma-ray measurements were to

be made on mixtures of plutonium isotopes (plus 241 Am) in an SRM for

nondestructive analysis calibrations, the efficiency calibrations of

germanium spectrometer systems were checked in the region below 400 keV

(fig. 7), and a thick (15 cm) planar detector was obtained in order to

obtain a flatter response in the 50 to 110 keV energy region.

Investigations showed that most existing calibration

points in the region below 122 keV were not trustworthy, so a special

effort was made to establish a few accurate points, independent of past

spectrometric measurements or nuclear-decay-scheme data.

Nal(Tl) well detectors of high and calculable efficiency

were used to measure accurately the emission rate of gamma rays at 60 keV

(from the decay of 241 Am) and 88 keV (from the decay of

109m

Ag). In the

20 and 30 keV regions, x-ray emission rates were directly measured with

detectors of established geometrical and intrinsic efficiency. The

accurate calibration points were then used to adjust an efficiency curve calculated from the collimator geometry, interaction probabilities,

transmission of intervening materials, and x-ray escape fractions.

These calibrated detector systems can be used with thin

sources of plutonium isotopes of known activity to measure gamma- ray

probabilities per decay, and then with sources to be distributed as NDA

standards to investigate scattering and absorption.

L. Lucas, J. R. Noyse, W. Mann

B. Destructive Analytical Chemistry

The goal of the Destructive Analytical Chemistry Task is to provide

standardization for wet chemical and mass spectrometric methodology used

for the assay of nuclear materials. This task has three component functions:

o Research to produce and certify Standard Reference Materials

(SRMs)

o Support for Measurement Assurance Programs (MAPs)

o Chemical and isotopic measurements to support NDA

19
Figure 6.

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET ( See instructions)

1. PUBLICATION OR 2 REPORT NO.. Performing Organ. Report No.l 3. Publication Date

4. TITLE AND SUBTITLE

The Half Life of Plutonium-240

5. AUTHOR(S)

Larry L. Lucas and James R. Noyce -4

6. PERFORMING ORGANIZATION (If joint or other than NBS, see instructions)

. NATIONAL BUREAU OF STANDARDS

7. C.ontract/Grant No.

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

8. Type of Report & Period. Covered

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, City. State. ZIP)

U.S. Department of Energy

Office of Safeguards and Security

Germantown, MD 20874

10. SUPPLEMENTARY NOTES

PH Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bi bl iography or literature survey, mention it here) The alpha- parti cl e-emission rates of solutions of plutonium-240 oxide were

determined from defined-sol id-angle-counter measurements. These results were

combined with composition data obtained from other laboratories, and the half

life of plutonium-240 was calculated to be 6552.2 yr. Associated with this

value is a standard deviation of the mean of ± 2.0 yr and a systematic uncertainty

1 imit of ± 13.8 yr.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and seporote key words by semicolons)

alpha-particle emission, half life, plutonium,- plutonium- 240, safeguards, special

nuclear materials

13. AVAIL. ABILITY 14. NO. OF

PRINTED PAGES

QQ Unlimited

| | For Official Distribution. Do Not Release to NTIS

| Order From Superintendent of Documents, U.S, Government Printing Office, Washington, D.C. 20402. 15. Price

QJ Order From National Technical Information Service (NTIS), Springfield, VA. 22161

20
Figure 7.

FITTING RESULTS FOR THE EXPANSION OF THE NATURAL

LOGARITHM OF THE EFFICIENCY FOR DETECTOR 1.

GOODNESS OF FIT = 0 . 9 7 9 1 5 1 E 0

A (-3) = 0.28571 7 E 7+,- 320813.

A

( -2 ) = - A ( - 1 ) = A ( 0 ) = - A ( 1 ) = -0

T t» ENERGY

1 88.037

2 122.063

3 140.479

4 1 65.853

5 1 71 .280

6 245.390

7 279.1 88

8

' 364.480

9 411. 795

1 0 433.927

87150.9 + , -

8 6 v

.

7 1 7 + , - 10.0116 + , -

. 1 5 9 8 6 4 E - 3 + , OBS EFF

0.000743700

0 . 000758000

0 . 000728000

0 .000652400

0 .000629800

0 .000427900

0.000358300

0 . 000253500

0 .00021 4700

0 .000203460

7949.46

67 . 8377

0.236749

0.281 965E -3

'/. RESIDUAL

-0 .0025

-0.0598

0 . 3 34 0

0 . 1 367

-0.6775

0.3922

-0 . 6264

0.0548

-0.7311

0.451

4

FITTING RESULTS FOR THE EXPANSION OF THE NATURAL

LOGARITHM OF THE EFFICIENCY FOR DETECTOR 2.

GOODNESS OF FIT =

A ( -3 ) — 0.211 960E

A < -2 ) = -66457.3

A ( - 1 ) = 669.481

A ( 0) = -8.84039

A ( 1 ) = -0 .532320E

FT tt ENERGY

1 88.037

2 122.063

3 140.479

4 165.853

5 171.280

6 245.390

7 279.188

8 364.480

9 411. 795

10 433.927

+

+ -3 +

OBS EFF

0.0011 69400

0.001214500

0.001171 500

0.001066400

0.001038200

0.000747000

0 .000640800

0 .000471 400

0 . 00041 31 00

0 .000389700

330160

.

8133.78

68 . 7024

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0.281387E -3

/ RESIDUAL

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21
When requested, and as needed, assistance is provided to other

domestic laboratories in government and industry. Assistance is also

provided to other countries and to international and/or multinational

organizations in the accurate measurement of certified reference materials.

1. Methodology for Chemical Assay of Nuclear Materials

High-precision and high-accuracy chemical assay techniques are essential if there is to be adequate safeguarding of the nuclear materials

in the fuel cycle. These techniques, in conjunction with well characterized

SRMs, help provide a sound base for materials measurement and accountability.

Chemical assay procedures are also essential to the preparation of highaccuracy primary reference materials of known isotopic composition for mass spectrometer calibration.

a. Uranium Assays

The goal of this project was to develop a method for the

high precision assay of 10-25 mg of uranium in separated isotope solutions.

The Davies-Gray titration is capable of the required precision of better

than one part in 104 but does require larger (2-3 g) samples for high

accuracy and precision. Since large quantities of separated isotopes are expensive, scarce, and in some cases, a radiation hazard, there was an acute need to develop a high precision assay utilizing less than 100 mg

of sample. When this work was initiated, no method existed which was capable of yielding better than 1 part in 104 precision on a sample of

less than 100 mg.

A manual titration procedure has been developed by a methodical study of the effects of various parameters upon the Davies-Gray

titration and through the application of improved techniques to the basic

method. The precision for this new method, for a 100 mg sample, is

nearly as good as would be determined from 2-3 gram samples by the con- ventional method. Alternatively, samples of 10 mg or less might be

titrated to the 0.05 percent precision level of the standard Davies-Gray

titration. The usefulness of such an improvement is the fact that no significant changes in equipment or chemistry is required.

The initial aspect of this research has been accomplished

within set precisions of 0.006 percent for 100 mg samples. Although

there is a consistent bias of 0.09 percent, this will not interfere in

the preparation of accurate calibration standards from two master solutions

of uranium separated isotope since the method would only be used to

certify isotope ratio standards. The results of this research will be

presented in part in an invited paper at an upcoming American Nuclear

Society meeting and is being prepared for submission to Analytical Chimica

Acta.

J. R. Moody

22
2. High Sensitivity Mass Spectrometry of U and Pu

a. Resin Beads

High-Precision and High-Accuracy mass spectrometry techniques

are essential to the measurement and safeguarding of nuclear materials.

In addition, the high sensitivity of the resin bead technique coupled

with the high precision and high accuracy of the thermal mass spectrometry

technique offers unique possibility for measurement and accountability.

High sensitivity isotopic measurements of uranium and

plutonium by thermal ionization mass spectrometry using an anion resin

bead as the emitter has been investigated. The use of the resin bead has

been studied for its promising advantages in facilitating shipping,

minimizing sample size and sample handling in the isotopic analysis of

uranium (U) and plutonium (Pu) for required nuclear safeguards measurements.

Some of the specific advantages of the resin bead technique result from;

(1) the selective absorption by the beads of U and Pu from the fission

and actinide products in dissolver solutions, (2) the ability to load and

analyze beads directly by mass spectrometry, and (3) the high ion yield

from the bead matrix which markedly reduces the required sample size and

thus, the potential radiation hazard.

The NBS effort in the U and Pu isotopic analysis program

has been directed at the critical evaluation of the resin bead technique

with respect to routinely achievable precision and accuracy. Efforts in

the previous year have been directed at the identification of the factors

which affect precision and accuracy as measured using NBS instrumentation

and mass spectrometric practices. In the past year, a round robin has

been organized to introduce other mass spectrometric laboratories which

have the capability of making high sensitivity measurements to the resin

bead technique and to receive, in turn, the critical evaluations of these

laboratories and a more general indication of measurement state-of-the-art

as related to high sensitivity U and Pu analysis.

A request to participate in the round robin was made to

all laboratories with the known ability to make high sensitivity U and Pu

measurements including military, government, industrial, and academic

laboratories, both domestic and foreign. Of the fifteen labs contacted,

eleven expressed interest in participating and received samples. Six of

these laboratories continued in the round robin exercise and formally

submitted data for all the phases of it. It must be emphasized that the

round robin was a voluntary exercise and did require a significant expenditure of effort by the participants. This level of effort required was

the primary reason expressed for inability to participate. The laboratories

that did participate generally had extensive previous experience with

either small particle handling or the resin bead technique.

The round robin was divided into four phases. The initial

phase consisted of beads of two different sizes that were fully loaded,

that is, the bead capacity was saturated with uranium. These samples

were designed to allow baseline measurements and calibration of instrumentation with relatively unlimited uranium, 300 or 30 nanograms. The

23
three other phases of the round robin consisted of samples containing U

and Pu alone and together with beads containing about 3 ng of the element(s)

In all phases of the round robin, both standards and unknowns were submitted

for analysis which allowed external standardization of the results.

Table 5 summarizes the round robin design. Samples were

shipped by isolating a known and limited number of beads for each sample

between an optical microscope well slide and flat slide. When it was observed that there was movement of the beads occurring in the slide

"sandwich" which had the potential of causing the beads to be crushed or

lost, the beads were immobilized in a drop of collodion diluted 1:10 with

ethanol. It was concluded that beads could be shipped confidently with

their integrity maintained in this manner.

The analysis of wel 1 -characterized unknowns in replicate

by the participating laboratories in the round robin has provided invaluable information concerning the precision and accuracy achievable

with the resin bead technique and high sensitivity mass spectrometry.

The fact that unknowns were prepared with the isotopic spikes 244 Pu and

233 U requiring the measurement of the major 244 Pu/239 Pu and 233 U/238 U

ratios maximized the evidence of isotopic fractionation. This fact is

especially important for plutonium since the only isotopic standards

available possess 240 Pu and 239 Pu as major isotopes and thus any uncer- tainty in corrections for fractionation extrapolated from these standards

is magnified. Measurement of the minor isotopes (< 100 ppm) has allowed

estimates of interference levels, which appear negligible, as well as limits of detection. The anecdotal information about instrumentation

used and measurement practices followed have indicated the generality of

the technique since single, double, and triple sector mass spectrometers,

both voltage and magnetic peak switching, and both electron multiplier

and Daly detectors in pulse counting operation were used. Figure 8

illustrates the results for a U and a Pu unknown.

This round robin has allowed a number of generalized

conclusions to be made concerning the resin bead sample loading technique.

These include the following: (1) The technique is convenient for shipping,

handling, and inventorying very small known amounts of uranium and plutonium

(2) a few nanograms of U and Pu can produce a signal intensity adequate

to make precise measurements of major isotopes, and (3) that laboratories

familiar with the handling of small samples can routinely use the technique.

Questions that were not addressed or were unanswered by this round robin

are, (1) the transferability of the technology to routine measurement

conditions where the care necessary to handle small samples or delicate

instrumentation may not exist, and (2) the ability to control fractionation

which may be inherently less than both conventional and other high sensitivity methods of loading uranium and plutonium. Table 6 summarizes the

accuracies and precisions achieved on the major isotopic ratios of the

unknowns A, B, C, D, E, and G.

J. D. Fassett, W. R. Kelly

24
TABLE 5. Resin bead round robin design.

Samples

Phase Element Bead Size Amount Standards Unknowns

I U 150 pm 300 ng 3 1

50 pm 30 ng 1 1

II U 150 pm 3 ng 1 2

III Pu 150 pm 3 ng 1 2

IV* U/Pu 150 pm 3 ng ea. 1 1

*Not completed at time of this report.

25
DEVIATION

(%)

REFERENCE

VALUE

+ 95% C.L.

REFERENCE

VALUE

±95% C.L.

MS DETERMINATION OF

URANIUM UNKNOWN C

Figure 8.

26
TABLE 6. Measurement, precision, and accuracy.

Unknown

Reported

Results

Isotopic

Ratio Value

Precision

Avg. Median

Accuracy

Medi an

Avg. Absolute Error

A 7 235^/238^ .12 .40% .18% + .33% .30%

B 7

235

(J/ 238U .10 .24 .25 -.05 .27

C 6 235jj^238jj .10 .18 .12 +.21 .14

233

U/

238

(J .08 .37 .27 + .19 .20

D 6

235

U/

238

(J .02 .41 .27 + .35 .25

E 5

244d ,239 d

P u/ Pu .61 .22 .18 + .43 .46

G 5

240 d ,239 d P u/ Pu .22 .10 .10 -.12 .08

27
b. IDA-80

NBS and the Central Bureau for Nuclear Measurements (CBNM),

Geel Establishment, Belgium, are jointly providing assay and isotopic

characterization for uranium and plutonium in a series of samples for

IDA-80. IDA-80 is a worldwide test program to assess the state-of-the-art

for interlaboratory measurement by isotope dilution mass spectrometry.

This measurement program focuses on the determination of uranium and

plutonium elemental concentrations as well as their isotopic composition

in solutions from nuclear installations and reprocessing plants under

routine operating conditions.

Thirty-nine samples were received at NBS including; input

for a reprocessing plant, both spiked and unspiked samples; synthetic

uranium and plutonium mixture, both spiked and unspiked samples; and a mixed uranium and plutonium spike. At NBS, the unspiked samples were

spiked with aliquots of SRM 993 ( 235 U) and SRM 996 ( 244 Pu) and separate

aliquots of the samples were spiked with the included spike solution.

The spike and sample mixtures were equilibrated by an oxidation-reduction

step and then the uranium and plutonium were separated and purified by

anion exchange separations.

The plutonium samples were analyzed by high sensitivity

thermal ionization mass spectrometry using ion counting detection. The

size of sample required per measurement by this technique was a nanogram.

This technique was utilized in order to minimize both radioactivity in

the laboratory and contamination of the mass spectrometer and represents

a factor of 1000 less than is required for conventional plutonium measurement

procedures using Faraday cup detection. Fractionation corrections were

made relative to the plutonium isotopic SRM 947 which was measured in

replicate throughout the plutonium measurement program. The 240 Pu/239 Pu

ratio of this standard was measured to 0.06 percent (la, N=28).

The uranium samples were analyzed by thermal ionization

mass spectrometry using a Faraday cage collector. Approximately two

micrograms of uranium were loaded onto each sample filament of a triple

filament rhenium ion source for analysis in the mass spectrometer. All

analyses were corrected for mass dependent isotopic fractionation by

comparison with SRM U-500, analyzed under identical conditions.

J. D. Fassett, J. W. Gramlich, L. A. Machlan

c. Mass Spectrometer Facility at New Brunswick Laboratory

The NBS mass spectrometer facility at New Brunswick Laboratory

(NBL), Argonne, Illinois was visited by scientists of the Mass Spectrometry Group in order to verify instrument performance according to established specifications and to verify that the support facilities were complete and functional. Furthermore, NBL personnel responsible for this

facility were instructed in all phases of sample loading and instrument

operation during these visits. In return, the staff scientist at NBL

responsible for this facility, visited NBS to receive more extensive

training in NBS developed mass spectrometric procedures.

28
Two of the most recent instrument changes in the basic NBS

design were incorporated in the NBL instrument. A turbomolecular pump

was installed which will alleviate the difficulties associated with

maintaining a liquid nitrogen supply to trap a mercury diffusion pump.

This type of pump has been evaluated and is presently in routine operation

at NBS. A pyrometer mount, one of the latest refinements in the making

of high precision measurements, was also installed. Since these visits,

NBL personnel have used the instrument extensively with demonstrated

measurement precisions of a few parts in ten thousand for the NBS uranium

series isotopic standards.

W. A. Bowman, J. D. Fassett, J. W. Gramlich

d. Pu Isotopic Reference Materials Working Group Meeting

The Second International Pu Isotopic Reference Materials

Working Group Meeting was held in Vienna, Austria, April 8-10, 1981.

Insofar as new reference materials are concerned, the top priority is an

equal atom mixture 239 Pu and 242 Pu for mass spectrometry. The need for

both CBNM and NBS to produce two different, rather than a common reference

material, was seriously questioned. In addition to the equal atom reference

material, the need for three plutonium isotopic reference materials for

isotopic analysis and non-destructive analysis (NDA) was discussed.

Reference materials of 90 percent, 75 percent, and 60 percent 239 Pu were

identified as sufficient to cover all projected needs of the nuclear

industry on either the national or international scale. At the present

time, CBNM has acquired 1.2 Kg of 60 percent 239 Pu and the Department of

Energy has identified and has on hold 1.5 Kg of 90 percent and 2.0 Kg of

75 percent 239 Pu. It was agreed that the chemical form should be medium

to high fired oxide, possibly as micro-spheres. The amount of material

required to provide a ten year supply of each reference material was estimated at 950 g.

The Working Group was informed that NBS would no longer

coordinate activities of the Group and would pass the duties to a representative of the Department of Energy's New Brunswick Laboratory.

B. S. Carpenter

C. Bulk Measurements

The Bulk Measurements Task occupies a position of strategic importance

in nuclear safeguards. The activities of the Task involve the determination

of the quantity of nuclear material in specific areas and processes in a nuclear fuel cycle plant and between specific areas and processes.

Measurements of mass, volume, density, flow, pressure, and temperature

contribute to the determination of the quantity of nuclear material; the

measurements of these physical variables interact with each other and

with the activities of the other three Tasks in the NBS Nuclear Safeguards

Program.

29
1 . Laser Doppler Velocimeter

The laser Doppler velocimeter was used to study the flow field

of a strut placed in a pipe flow. Figure 9 shows the geometry of the

strut and defines the coordinate system. In figure 10 is shown the mean velocity across the pipe diameter at several locations downstream of the

strut. The locations are defined in figure 9. At any point in the flow

the velocity is characterized by a mean value as shown in figure 10 and a fluctuating part. Figure 11 shows the power spectrum of the velocity

fluctuations measured at the point x = 3 cm, y

= 0.5 cm. Two sharp peaks

are distinguishable and correspond to velocity fluctuations caused by

vortex shedding from the strut. The slowly varying component of the

power spectrum in figure 11 is due to turbulence. Using the data in

figure 11 it is possible to determine the energy contained in the vortex

fluctuations (area in the peak), and the energy contained in the velocity

fluctuations due to turbulence (area under the peak). Figure 12 shows

the energy in the first vortex peak, the second vortex peak, and turbulence,

all a function of position across the pipe diameter. Vortex visibility

is defined as the ratio of the energy contained in the vortex peak to the

energy in the background turbulence. Figure 13 shows vortex visibility

as a function of the position along the pipe diameter. The data summarized

in figure 13 will be of great utility in the design and use of vortex

shedding flow meters.

T. T. Yeh

2. Correlation Flowmeter

Improvements to the correlation flowmeter were implemented. A new capacitive probe was designed and constructed in such a way as to

separate the high voltage (10 vpp) driving signal, which is applied to

the active plate of the capacitive probe, and the sensing and balancing

electronics which are attached to the ground plate of the probe. It was possible to null the bridge to about 25 pV which is the rms amplitude of

the noise. A circuit to automatically balance the bridge was designed,

constructed, and debugged. The circuit consists of five ADC and five DAC

elements interfaced to a AM Z8002 computer and to the analog inputs and

outputs of the bridge circuit. Software development for the control

function has started. Construction has started on a "calibrator" for the

correlation flowmeter. The calibrator is an adaptation of the one used

for the laser Doppler velocimeter and it will allow us to introduce known

disturbances into the correlation flowmeter. This will facilitate the

design of sensing electrodes and the development of algorithms for computing

various moments of the correlation function.

A. Gaigulas

30
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32
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34
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35
3. Tank Volume Calibration Algorithm

An algorithm has been developed to relate the volume of a nuclear process solution at its temperature to the calibration performed

with water at a temperature near ambient. A manuscript titled "A Tank

Volume Calibration Algorithm" by F. E. Jones is undergoing editorial

review. Another manuscript titled "Accountability Tank Volume Calibration

Data," by F. E. Jones, J. F. Houser, and R. M. Schoonover is undergoing

editorial review also.

F. E. Jones

4. Determination of Water in Plutonium Dioxide

A manuscript covering the measurements of the moisture content

of plutonium dioxide, made at the Hanford Energy Development Laboratories,

Richland, Washington, titled, "Determination of Water in Plutonium Dioxide,"

by F. E. Jones, is undergoing editorial review.

F. E. Jones

D. Applied Mathematics

The applied mathematics effort in support of safeguards consists not

only of independent efforts, but also of collaborative efforts with other

scientists at NBS.

During the past year a number of articles were published on statistical

approaches to Safeguards Measurements and the Safeguards Problems. These

are listed in the publications section of this Report.

E. Safeguards Systems Studies

The objective of Safeguards Systems Studies is to provide technical

support to the safeguards program of the DOE Office of Safeguards and

Security (DOE/OSS) and the U.S. Initiative Program for International

Safeguards. Systems analysis studies are performed leading to a more effective utilization of data and information from all sources for

achieving safeguards goals. Program efforts contribute sound technical

input for design, development, and operation of DOE/OSS and domestic

nuclear plant programs that will be effective in protecting against

covert diversion of special nuclear materials (SNM) by persons authorized

access to the material or international programs aimed at detecting

diversion by the State. Task activities addressed completion of the

Concepts for Safeguards Information Systems study, modification of Diversion Path Analysis Computer Program 2, and adaptation of Diversion Path

Analysis concepts to evaluation of international safeguards as applied by

the International Atomic Energy Agency.

36
1. Study of DOE Safeguards Measurement Implementation Needs

Nuclear material measurement problems, from a safeguards point

of view, currently exist at the major DOE processing facilities and can

be expected to magnify as future high-throughput facilities come on-line.

To address these problems, measurement methods have been developed for a significant number of material classes in the DOE complex, however,

substantial effort on the part of development laboratories and DOE con- tractors may be required to adapt many of the methods for site-specific

application. Administrative problems may also hinder technology transfer,

or implementation of proven methodology, to the process line. Thus, any

actions taken to improve the material control and accounting subsystems

of the safeguards system must address not only the technical problems but

the administrative issues as well. In addition, uniform documentation

suitable for cost benefit analyses and the establishment of implementation

priorities throughout the DOE complex are needed.

The objectives of the DOE Safeguards Measurement Implementation

Needs Study were to identify the material control and accounting subsystem measurement needs at selected DOE contractor facilities and to

recommend a prioritized plan for transferring technology presently available

at development laboratories to address site-specific needs at these

facilities. The significance of the administrative issues in regard to

technology transfer was recognized early in the study; their identification,

therefore, also was included as an objective.

To achieve these objectives, interviews were held with key

Operations Office and contractor staff concerned with safeguards measurements at the following sites:

o Savannah River Operations Office (SR)

Savannah River Plant [DuPont] (SR);

o Albuquerque Operations Office (AL)*

Rocky Flats Plant [Rockwell International] (RFP);

o Richland Operations Office (RL)

Hanford Engineering Development Laboratory [Westinghouse] (HEDL)

Pacific Northwest Laboratories [Battel le] (PNL)

Rockwell Hanford Operations [Rockwell International] (RHO)

The final draft of the report discussing the findings of the

study together with the conclusions drawn from them has been prepared.

The technical problems and administrative issues identified at each site are listed separately even though the same class of problem or issue was identified at more than one site. When this was the case, it can be seen that the perception and/or impact of the problem or issue often varied

from site to site. By maintaining the separate listings, these variations

are preserved.

S. Bologa, J. Schleter, M. D. K. Maltese

37
IV. MEASUREMENTS AND STANDARDS FOR NUCLEAR WASTE MANAGEMENT - A TECHNICAL

OVERVIEW

The Program of Measurements and Standards for Nuclear Waste Management

was established late in Fiscal Year 1980, after an extensive study of the

materials and measurements problems involved in nuclear waste management.

Thus, this technical overview for Fiscal Year 1981 represents the first

full year of operation as a program.

The technical efforts for the Nuclear Waste Program are divided into

the following areas: (1) Waste Forms Leachability Mechanisms; (2) Waste

Forms Research, Reference Materials Data and Measurement Methods; and (3)

Containers, Backfill and Math Support.

A. Waste Forms - Leachability Mechanisms

This task reviewed existing efforts by others, as well as carried

out experiments in selected areas at NBS to improve and understand the

mechanisms involved in leaching of radioactive waste species from an immobilizing matrix. In order to accomplish this, the role or effect of

radiation, mechanical properties, microstructure, microchemistry, thermodynamics, transport mechanisms, thermochemistry, and various other disruptive processes were investigated.

1. Leachability Concepts and Theory

A survey of the literature on the theoretical modeling of leach

measurements was conducted utilizing online computer based search codes.

A primary finding was that the great majority of modeling efforts have

been concerned with closed-form analytic solutions to the normal diffusion

equation. This has necessitated a number of approximations which limit

the value of these works to short-time evaluations of leaching trends.

These treatments do not give adequate considerations to the mechanistic

aspects of the transport phenomena. This is unfortunate since a detailed

understanding of the leaching of radioactive wastes, and hence the opportunity to make long-term predictions, requires a corresponding understanding

of the transport mechanisms.

In response to the foregoing situation, it was decided to

pursue a threefold approach to the problem of modeling the MCC leach test

measurements. The first step was to consider the added flexibility that

would be obtained by using numerical rather than analytical solutions for

transport problems. The second step was to develop a model that would

emphasize the role of chemical and physical mechanisms in the transport

of waste material in and from a solid host substance. The third step was

to apply the model to the analysis of MCC measurements.

We found that diffusion problems could be treated very powerfully

by numerical methods when compared to the rather restrictive limitations

of the solutions found in closed forms. Spatial and time dependent

diffusion parameters could be included with equal ease, as could dependences

on concentrations and chemical reactions. As an illustration of the

added power of numerical methods, a problem applicable to the phenomenology

38
of leaching mechanisms was treated. We considered a leachant A that

could react with a constituent B of the solvent and thereby form a reactant C. Compound C could adhere to the solid-solvent interface

causing a change in the diffusion characteristics of the system.

Allowing the adhered layer to flake off periodically, we found it

possible to produce either a linear ("matrix dissolution") or a parabolic

("simple diffusion") leach rate depending on how the data points were

sampled. Neither of the phenomenologically suggested mechanisms was

correct.

The phenomenological approach to the modeling of leach measurements is useful for the discussion of short-time trends, but as seen in

the preceding example, it is only crudely related to the actual transport

mechanisms. Therefore, as an important alternative, a microscopic formulation of the diffusion and leaching process was developed. Based on the

use of a recurrence relation for a random walk on a lattice, this model

has several attractive features. (1) When the continuum limit is taken,

a nonlinear diffusion equation with appropriate boundary conditions is

recovered. (2) The incorporation of specific molecular mechanisms is a straightforward task. (3) The numerical solution of the model can be

easily and inexpensively achieved.

To illustrate the application of this new model to the MCC-1

leach test measurements, two applications were considered. First, to

establish a reference case, simple exchange and diffusion of Na+ and H3 0+

ions between Si02 glass and a water solvent was modeled. Then, the Si02 matrix was allowed to dissolve due to the reaction of OH- solvent ions

with the hydrated glass surface. Figure 14 shows that leached amounts

over a 28 day period can be significantly affected by surface interactions.

R. Mountain, R. Munro

2. Radiation Effects

\ This effort was initiated to study the effects of radiation on nuclear waste forms. The study was designated to simulate long term

radiation damage to the integrity of waste forms and to characterize the

structural changes in the waste forms both macroscopically and microscopically. Our purpose is two fold, i.e., to conduct the feasibility study

of, (1) using NBSR as a viable irradiation source for radiation damage

study, and (2) establishing neutron measurement techniques to complement

the more common x-ray methods.

Li-6 and B-10 neutron activation methods were chosen to simulate

alpha particle and transmutation effects. Activation methods are preferred because the MCC-6 recommended Cm- 244 doping process would require

long waiting time and special handling. The use of the NBSR research

reactor as a neutron source gives further ability in studying neutron and

Y effects.

The total radiation dosage and dose rate given to the waste

form can be moderated by varying the amount of Li and B dopants and by

39
Amount

leached

(arbitrary

units)

Figure 14. Leaching results with (upper curves) and without (lower curves)

matrix dissolution at the surface. The concentration profiles

are after 2, 14, and 28 days, moving from right to left. With

surface dissolution, the amount leached grows linearly with time.

Without surface dissolution, the amount leached grows approximately

as time to the power 0.6 (i.e., T**Q.6).

40
putting the sample in different positions in the reactor. This also

allows one to change the n/y or a/y ratios to qualitatively study synergistic effects.

2+ 3+ The waste form currently under study is magnetopl umbi te

(X^ 0 ^). This is one of the four ceramic phases developed to

contain high-level waste from the Savannah River Plant operations. Two

natural Li doped magnetopl umbi te samples (LiogLao^AlnOjy 5 ) were

supplied to us by the Energy Systems Group of Rockwell International.

X-ray and neutron diffraction patterns of the sample were taken

as microscopic bench marks for the pre- irradiation and small angle neutron

scattering facilities are used to characterize the macroscopic properties

of the sample. The sample was enclosed in sealed aluminum containers and was exposed to thermal neutron fluence of 1.2 x lO20 n/cm2 to simulate

the saturation a dosage. After irradiation, the sample was allowed to

cool down for 30 days before examined again by neutron and x-ray techniques

to characterize its post- irradiation conditions. These pre- and postirradiation examinations will then be correlated with the result of

Teachability tests which will be conducted by the Rockwell International

Group.

3 . Mechanical Properties

One of the primary objectives of this work has been to determine

the susceptibility of the glasses proposed for nuclear waste encapsulation,

to subcritical crack growth and microcracking. Crack growth data has

been obtained on a simulated waste glass composition in both moist air

and H2 0 . The glass was formulated by NBS based on a composition suggested

by Battel le Northwest Laboratories. The glass was melted, cast, and

annealed, and cut into double cantilever beam specimens. Crack velocities

from 10 -11 to 10-4 m/s were obtained as a function of stress intensity,

Kj. As with most glasses, crack velocities were higher in water than in

air. Data is now being obtained at lower velocities to determine if a stress corrosion exists for this composition.

The possible acceleration of stress corrosion by gamma irradiation is also being investigated. A fixture for obtaining crack growth

data in the NBS gamma-ray source was designed and built. Baseline data

on a soda-lime-silica glass has been obtained. A few preliminary data

points have been taken on this same glass in a gamma-ray environment.

A fixture has also been designed and built to allow us to

determine the effect of nuclear recoil on the strength and crack propagation behavior of glasses and ceramics. Baseline strength and crack

propagation data have been obtained on two borosilicate glass compositions.

By exposing these glasses to a thermal neutron flux, a transformation of some of the boron of lithium occurs with the production of an alpha-particle.

The nuclear recoil could lead to residual tensile stresses in the glass

which would produce lower strengths and possibly a lower resistance to

crack growth. Experiments to evaluate these effects are planned for the near future.

S. Freiman, A. C. Gonzalez, S. M. Wiederhorn

41
4. Phase Stability

During the current year an effort was made to begin to understand

the structural stability of crystalline materials containing large cations,

such as Cs

+

in hollandite. This work was necessary as there are few, if

any, data concerning the thermal and structural stability of hollandite

-J- -f- minerals containing Ba ions and/or Cs ions in the channels of the

Ti-hol landite network. This crystalline phase is the most important of

the Cs-containing crystalline constituents of "Synrock" which is under

current investigation as a possible host for nuclear waste.

As part of the general studies, the compatibility relations were re-examined for the system Ba0-Al 2 03 -Ti02

. The subsolidus relations

in this system had been previously reported by Guha [J. Solid State Chem.

34 , 17 (1980]. The primary phase fields were roughly mapped so that

small single crystals could be obtained of all the phases. The diagram

shown as figure 15 should be considered as very tentative. It has been

drawn to be consistent with all the experimental data obtained in the

present study, but many more experiments would be needed to more accurately

locate the phase boundaries. Single crystals of each of the phases were examined by x-ray diffraction with a precession camera and the unit cell

dimensions and space group symmetry of the three ternary compounds are shown in table 3. It should be noted that the hollandite single phase

was found to melt directly to a liquid of approximately the same composition at 1480 ± 2 °C.

A tetragonal hollandite had been previously reported in this

system by Ringwood [Acta Cryst. B36 , 2913 (1980)] and other hollandites

have been reported in similar systems by Cadee [Acta Cryst. B34 , 3554

(1978)]. Single crystals of hollandite grown from the primary phase

field of the ternary system BaO: Al 2 03 :Ti02 show much stronger diffuse

scattering characteristics than do the hollandite crystals grown using a flux containing CaO and Zr02 (a mixture of hollandite, rutile, and zirconal ite).

Although the superstructure spots have stronger intensity they are still

very diffuse and disk shaped rather than spherical.

Phase equilibria in the system Ba0-Mg0-Ti02 was also examined,

as a tetragonal hollandite phase has previously been reported in this

system by Dryden and Wadsley [Trans. Faraday Soc. 54, 1574 (1958)]. No

tetragonal hollandite was encountered in the previously reported range of

compositions, Ba (Mg Ti 0 )CL c (1.14 > x > 0.67) which had been synthesized

by a Verneuil technique. However, a solid solution region of a monoclinic

distorted hollandite structure was synthesized between 1:1:6 and 1:1:5

Ba0:Mg0:Ti02 or Ba

x (MgxTig_x

) O^g (1.33^ > x > 1.14g). The difference in

composition and structure is unexplained at this time. Substitution of

SrO for 10 mole percent of the BaO made little or no difference in the

unit cell dimensions and symmetry. Reduction of the monoclinic phase by

heating in N 2 at 1400 °C caused an increase in volume of the unit cell

but little change in the amount of monoclinic distortion.

42
BaO

1923

43
In addition to the hollandite, two new phases, never before

reported, were encountered in the Ba0:Mg0:Ti02 ternary system at the

1:1:3 and 1:1:6 compositions. Single crystals of all three ternary phase were prepared from compositions determined to be in their primary phase

fields as shown in figure 16. The unit cell dimensions and symmetry are also listed in table 7.

The single crystals of the hollandite phase were found to have

unit cell dimensions similar to the end member of the solid solution with

the maximum distortion and the maximum BaO:MgO content corresponding to a composition of about 1:1:5. The superstructure found in these single

crystals is the sharpest and most intense of any of the hollandite phases

encountered in the present study. In addition the superstructure was found to be clearly incommensurate and not of exactly the value corresponding to the trippled c axis which had previously been suggested by Cadee.

High temperature x-ray diffraction powder patterns were obtained

from the compositions 1:1:5, 1:1:5. 5, and 1: 1: 6BaO: MgO: Ti02 as well as for the composition 0. 9BaO: 0. ISrO: 1. QMgO: 5Ti02

. The monoclinic lattice

of the hoi landite- type was found to transform to tetragonal in all com- positions. The transition temperatures in the Ba0:Mg0:Ti02 compositions

decreased with increasing Ti02 content, ranging from about 265° ± 15 in

the 1:1:5 and 1:1: 5. 5 specimens to 110° ± 10° in the 1:1:6 composition.

The transition temperature in the 0. 9BaO: 0. ISrO: 1. OMgO: 5Ti02 specimen was apparently higher at about 340° ± 40.

The compound BaMg6 Ti 6 0 19 is apparently isostructural with

magnetoplumbite and barium hexaferrite and, by analogy, can be called

barium hexagei kiel ite. No experiments have yet been conducted in this

study in the system BaO: FeO: Fe2 03

: Ti02 but it may be predicted that the

+2 +4

corresponding compound BaFe^ Ti^ 0^^ (barium hexai lmenite) is a stable

phase in the system and probably forms a solid solution with BaFe 12 0 19 , barium hexaferrite. In the four component system Ba0:MgQ: Al 2 03 :Ti02 , a solid solution between barium hexagei kiel ite and barium hexai uminate can

+2

be predicted, as well as the hollandite solid solution, with both Mg

+3

and A1 in the framework. Both solid solutions should be equally useful

host lattices for incorporation of Rb , Cs , and Sr in nuclear waste

ceramic systems, and have been shown in this study to be in equilibrium

with each other.

Crystals of a hoi landite- type phase were also obtained in melted

specimens prepared in the ternary system BaO: Li 2 0:Ti02. Apparently Li + +4 can also be used to substitute in the Ti lattice to balance the charge

+2 +1

of the Ba and Cs ions.

To determine the amount of Cs

+ which could be incorporated in the

hollandite structure, preliminary studies have been conducted in the

systems Cs 2 0: MgO: Ti0 2 , Cs 2 0: A1 2 03

: Ti02 , and BaO: Cs 2 0: A1 2 03

: Ti02

. The

44
Figure 16.

45
TABLE 7. Unit cell data of titanate phases synthesized during

phase equilibria studies of ceramics for nuclear waste encapsulation.

Composition

Space

Group a b c P

* y

BaOSA^Og-TiO^ Pnnm,Pnn2 7.139 4.865 13.598

3Ba0-5Al

2

0

3

-Ti0

2 C2/m,Cm,C2 15.754 11.341 4.985 109.5

Ba

x

A1

2x

Tl 8-2x°16 I4/m, 14,14 9.94 2.920 8.122

(x * 1.23-1.14)

BaO-MgO *3Ti0

2

C2/m,Cm,C2 15.208 3.899 9.109 98.5

Ba0-6Mg0-6Ti0

2

P6

3mmc 5.935 23.37

Ba

xM9x

Ti 8-x°16 I 2/m, 12 9.920 2.992 10.256 91.5 8.528

(x -V 1.33-1.23)

Cs

2

0*Al

2

0

3

*2Ti0

2

Pbnn 9.973 5.480 9.025

Cs A1 Ti 0 x x 8-x 16 I4/m, 14, 14 10.194 2.938 9.476

(x 'v 1.66-1.33)

CsxH9

x/2

Ti

8-x/2016 I4/m, 14 , 14 10.278 2.970

(x ^ 1.45)

*Value of the modulation vector (in real space) for the incommensurate

diffraction effect observed along the unique axis in the hollandite

structure type.

46
hollandite phase has been previously reported by Beyeler and Sobuler

[Solid State Ionics 1, 77 (1980)] to occur in the system containing MgO,

but not in the ternary system containing A1 2 03

. The single phase tetragonal

hollandite structure was found to occur at approximately 1:1:10 in the

Cs20:Mg0:Ti02 system or ^ s x (^9

x/2^ 1 8-x/2^16

= Another non- stoichiometric phase originally reported by Reid, Mumme, and Wadsley

[Acta Cryst. B24 , 1228 (1968)] was also confirmed to exist in the system

Cs 2 0:Mg0:Ti02 at a ratio of about 1:1:4. 7. However, x-ray powder diffraction

patterns of specimens in the system Cs 2 0: A1 2 03

: TiO^ are very complex and

could not be directly interpreted in terms of a hollandite phase corresponding

to Cs (A1 Ti 0 )01C . Single crystals were obtained of a new phase correx x o-x lb

sponding to a compound at a composition CsAlTi04. The unit cell dimension

and symmetry, given in table 1, together with the observation that this

phase is pseudohexagonal , indicate that it probably has a structure very

similar to CsAlSi04. There is no sign of the second phase found in the

MgO system, even though this phase had originally been suggested to be

present in the Cs 2 0: A1 2 03

: Ti02 system. Instead a tetragonal hollandite

occurs, but in solid state preparations at one atmosphere of air, or in a sealed Pt tube, compositions between Ti02 and CsAlTi04 are always three

phases. A single phase hollandite can be synthesized by the application

of a small amount of pressure at an as yet undetermined composition

between about Cs A1 Ti 0 01C (1.66 > x > 1.33). Apparently, at one atmosphere total pressure, there is a competition for the Ti

4

ion between

6-fold (Ti02 ) and 4-fold (CsAlTi04 ) coordination. Under these conditions

single phase hollandite cannot be synthesized and may be only metastable.

It is apparently stabilized by a small amount of pressure. It may be

predicted that a slight increase in the size of the impurity ion incorporated in the lattice will also stabilize the formation of the hollandite

lattice and therefore solid solution with ^ s xM9

x/2^ 1 8-x/2^16 s ^ ou ^

. +4

increase the stability as would incorporation of the Ti as the reduced

+3

ion Ti . In the four component system, BaO: Cs 2 0: Al 2 0

3 :Ti02

, it was found that in the hollandite lattice about 20 mole percent of the BaO

could be replaced by Cs 2 0 with a corresponding increase of the A1 2 03

content. An additional Cs 2 0 content caused the phase CsAlTi04 to occur

in the specimens prepared at one atmosphere total pressure. It can be

assumed that a complete series of solid solutions can be prepared between

Ba Al„ Ti 0 „ 0, c and Cs A1 Ti 0 0, c by the application of a small amount

X £~X o~<iX lb X X o~X lb

of total pressure.

Ceramic samples were prepared for AC impedance measurements from

the following compositions: BaO: A1 2 03

: 4. 5Ti0 2 , 0. 5Ba0: 0. 5Sr0: A1 2 0 3

: 4. 5Ti02 , 0. 9BaO: 0. ISrO: A1 2 0 3

: 4. 5TI02 , 0. 9BaO: 0. lCs 2 0: A1 2 03: 4. 5Ti02 , 0. 9Ba0: 0. 1K2 0:

A1 2 0 3

: 4.5Ti02 , and BaO: A1 2 03

: 5Ti02

. The ceramic pellets were generally

all about 86 percent theoretical density. In addition the oxidation of

partially reduced BaO: A1 2 0 3

: 5Ti02 hollandite was examined as a function

of different temperatures in air and pure oxygen.

The phase equilibria results were utilized to synthesize single

crystals of the various phases encountered in ternary and quaternary

47
combinations within the Cs 2 0-Ba0-Sr0-Mg0-Al 2 03 -Ti02 system. All crystals

of incongruently melted phases were grown by very slow cooling of compositions within the primary phase field of the desired compound. Only for

the Cs-Al-Ti hollandite phase was it necessary to use an additional flux.

In this case a small amount of CsF was sufficient to enable small single

crystals to be grown in sealed Pt tubes.

Dr. Arne Olsen, a foreign guestworker at the National Bureau of

Standards, examined some of the specimens prepared for this study by high

resolution electron microscopy and electron diffraction. He used the two

STEM units at NBS, the Philips EM 400 Microscope in the Center for Materials

Science and the JEOL 200 CX in the Center for Analytical Chemistry. A

summary of his conclusions are included below.

No commensurate superstructures were found in this study.

There seems to be a correlation between the diffusiveness of the superstructure reflections, the intensity of the diffuse planes normal to c*

(or b* in the monoclinic case) and the period of the superstructure. For

^ ax^^2x^ 1 8-2x°16 hollandites the superstructure reflections are sharp,

but become more diffuse at larger deviations from the commensurate value

x/c=2. There are no (or only weak) diffuse planes for all the ^ ax^^2x^

1*8-2x^l6

hollandites. The Ba

xMgxTig_x0^g hollandites have superstructures close

to 3c. The superstructure reflections are still very sharp, but the

diffuse planes have higher intensity than for ^ax^^2x^ 1 8-2x^l6‘ * n Cs A1 Ti 0 case the superstructure reflections are in general diffuse

x X o~x lb

and there are diffuse planes through all the superstructure reflections.

It is important to notice that there are large variations in

the intensity within the diffuse planes. The intensity is maximum along

the (110) directions and is very low in (100) directions. This indicates

that they reflect the correlation between the structures in neighboring

+2 + . tunnels. Only tunnels of one size have been found for Ba and Cs in

all the investigated compounds. The incommensurate superstructures

+2 + appear to be due to the distribution of Ba and Cs ions and vacancies

within the tunnels.

The heat treatment of the Ba-Mg and Cs-Al hollandites does not seem to affect the period of the superstructure. For the Ba-Al hollandites

the heat treatment seems to affect the period of the superstructure, but more experimental data are necessary in order to make a firm conclusion.

5. Mass Transport in Crystalline Materials

Materials having a hollandite type structure and containing

alkali metals have been studied extensively in recent years. This class

of compounds was considered as a model quasi-one dimensional fast ion

conductor. For example, K-hol landite, ^

x^9x/2^ 1 8-x/2^16

< x < 1.0)

is one of such materials. The reported intrinsic conductivity of a

48
K ' Mgx/2

Tl 8-x/2°16 single crystal at room temperature is as high as 0.46

S/cm; however, this high ionic conductivity is likely to be reduced by

the presence of those grain boundaries in a ceramic. Here we use the

term "grain boundaries" generally to describe all those structure imperfections which are able to block the conduction of the mobile ions. In

the case of Cs in the hollandite structure, the Cs ions are expected to

be mobile. Since the Cs ion is much larger in size, the change in coor- dination is expected to effect the ion conduction in Cs-hol landite.

During this study period we have examined several ceramic

samples of pure hollandites and hollandites containing a K and Cs ions.

Those pure hollandites were studied to serve as a guide for material

preparation. K-hol landites were selected as reference for its wider

literature base. Pure hollandite ceramics, Ba Al 0 Ti 0 0 0 1C and

x zx o~zx lb

Ba Mg Ti 0 0 1C were pressed at 10,000 psi and sintered at 1400-1450 °C

X X o“X lb

for 4-6 hours in air. Ten percent of BaO was replaced by Cs 2 0 or K2 0 to

form Cs-hol landites or K-hol landites. These samples were sintered at

1275-1350 °C for 6 hours and annealed at 950 °C for 24 hours.

I^x^gx/2^ 1 8-x/2^16 ceramics were also prepared at the same conditions as above. The density of these ceramics was about 85-90 percent of theoretical

value. To avoid possible reduction of Ti02 due to high temperature

sintering all samples were carefully annealed and show milk white color.

Platinum paste was used to make electrical contacts. AC impedance spectra

from 100 Hz to 10 MHz were measured to determine the electrical conductivity

of the sample. Temperature dependence of the conductivity was made from

100 °C to 800 °C in air.

Figures 17 and 18 show the impedance spectra of (Cs,Ba) (Al,Ti) 0 01C x o

- x lb

at 400 °C and 600 °C. Total conductivity can be obtained by fitting high

frequency data to a Cole-Cole distribution function. Since the conductivity

of the hollandite is distributed, the computer fitting results in a large

uncertainty. More detailed analysis of the impedance spectra requires a suitable detailed model which is not available at the present stage. The

fact that the impedance spectra of all hollandites behave in a similar

manner suggested the ion transport in the hollandites may be governed by

a similar mechanism. These spectra are reproducible. The thermal cycle

was repeated from 100 °C to 800 °C for over 15 times. No changes were

seen. This is shown in figure 19 where the AC conductivities at 1 MHz

from different runs were plotted against temperature. In figure 20 we compare the conductivity of high conducting K

xM9x/2

Tl 8~x/2°16 wlth

Cs A1 Ti 0 0, c

. We found that the conductivity of Cs hollandite is about

x x o“X lb

three to four orders smaller than that of K-hol 1 andite. The activation

energy of the K compound was 0.9 eV and that of the Cs compound was 1.5

eV. The large difference in the conductivity and activation energy are probably due to the size of the ion. The effect of interionic potential

due to K and Cs ions should be considered.

49
7

0.0 1.0 X 10 7

Z" (0hm~cm)

Figure 17.

50
o

• m **" X — O ! O

oj Z

' ' (Ohm-cm)

M

Figure 18.

51

(Ohm-cm)
CONDUCTIVITY

(S/cm)

-A

1000/TCK)

Figure 19.

52
CONDUCTIVITY

(S/cm)

-2

1000/TCK)

Figure 20.

53
B. Waste Forms - Research, Reference Materials Data and Measurement

Methods

This task includes the development and dissemination of generic

research materials with well -characterized elemental composition to aid

in the development and promulgation of leach tests. Materials (glass)

with varying leach rates containing non- radioactive cesium, strontium,

etc. , were pi anned.

1. Phase Equilibria Data for Nuclear Waste Form Materials

A survey was made of pertinent phase equilibria diagrams to

determine if enough data was available in the literature for a compilation

to be prepared of "Phase Diagrams for Ceramists Pertinent to Nuclear

Waste Management." In addition to searching Volumes I-V of "Phase Diagrams

for Ceramists" several computer searches were undertaken using Chemical

Abstracts, DOE reports, etc. The total number of published phase diagrams

specifically applicable to the glass and ceramic compositions suggested

for nuclear waste encapsulation are limited to only about 5-6 diagrams,

mostly of simple binary or ternary systems. Most of the pertinent diagrams

have not been studied in enough detail to have appeared in the literature.

It may, therefore, be concluded that the study of phase diagrams of the

type reported in this section is very important in order to determine the

phases which may be expected to occur in ceramic systems in which the

"tailoring" of compositions is in exact due to knowledge of the real

composition of the waste.

R. Roth

2. Leachability Research Materials

The overall objective of the subtask was to develop two glasses

for use as research materials in leach testing. These materials are needed for standardization of leach testing, assuring that all laboratories

are testing the same material. If all laboratories obtain comparable

results for the leach rate of the research material then data produced

using the procedure involved can be compared with confidence.

In addition to the glass development work, NBS also supplied,

at the request of the MCC, a borosilicate glass for use in the MCC-1

round robin test. The material was an available standard glass which is

very homogeneous.

In conjunction with the MCC-1 and other interested parties, it was decided that the first research material to be produced, RM8400,

should have a leach rate similar to that of an average borosilicate waste

glass. Further discussion with the MCC and representatives of other

organizations involved in leach testing resulted in the choice of PNL

7668 glass composition as a starting point for development of RM8400.

This composition was chosen because there has been a great deal of experience with this glass. It has been well characterized and would appear

to be suitable for production in the quantity required, 1000 lb. However,

7668 as such has several drawbacks as a standard material. In addition

54
to the leach rate specification the homogeneity of the research material

is of prime importance. One of the drawbacks of the 7668 formulation is

the fact that the high iron content along with lesser amounts of Cr2 03

and NiO result in a nearly opaque glass. This prevents use of optical

techniques for determining homogeneity and requires the use of instrumental

techniques that are time consuming, expensive and less precise than the

optical methods.

To facilitate homogeneity determination, a glass based on PNL

7668 was produced containing no iron, nickel, or chromium, NBS K1620.

This results in a transparent glass, though slightly colored by the rare earths present, which allows the use of optical techniques for determining

homogeneity. The composition for PNL 7668 and NBS K1620 are shown in

table 8. The K1620 glass was then characterized to determine if it would

be suitable for use as a research material. This included determinations

of physical properties needed by the glass manufacturers, investigation

into the presence of phase separation and determination of leach rate.

Also a series of glasses were produced to investigate the effect of

various oxides and different raw materials on the final homogeneity of

the glass. The physical properties of K1620 are shown in table 9, the

leach rate, along with 7668 data, is shown in table 10. Investigation of

phase separation indicated that under normal manufacturing conditions

phase separation should not be a problem with this glass.

The characterization of K1620 showed that this composition

would be suitable for use as RM8400. In light of this decision purchase

specifications were written to obtain 1000 pounds of this glass. A

solicitation for bids was made by the NBS Contract Office. Bids were due

to be opened October 5, 1981.

Development of the second research material, RM8401, was initiated

after work on RM8400 was underway. It was desired to produce a glass

having a release rate approximately two orders of magnitude lower than

RM8400 and contain other elements/oxides of interest that were not in

RM8400, i.e., Re02 and I. As part of this portion of the subtask a series of compositions was designed, in conjunction with the Center for

Applied Mathematics and Center for Analytical Chemistry, using K1620 as a base glass that would allow determination of the effect of individual

oxides on leach rate, using the MCC-1 test. These leach tests are currently

in progress. In addition to these glasses, several other glass compositions

were produced with the objective of arriving at a composition with the

appropriate release rate. Since MCC-1 is time consuming a preliminary

test was developed for use in screening candidate glasses, promising

materials would then be subjected to the full MCC-1 test. The screening

test used was continuous flow extraction by distilled water at constant

temperature (100 °C) rather than the frequently used Soxhlet extractor

with its alternating syphoning cycles. The test chamber was continuously

flushed with N 2 to assure the same atmosphere at all times. This was

used since tests had shown that the leach rate was sensitive to the

atmosphere in the chamber. The samples used were rods with a nearly

square cross-section, approximately 3 mm on a side, with a length of

approximately 75 mm. A saw cut finish on the glass was used in all

55
TABLE 8. Glass composition.

PNL 7668 NBS K1620

s i °2 41.21 46.10

B 2°3 9.80 10.96

Na

2

0 13.01 15.32

ZnO 5.14 5.75

Ti0

2

5.07 3.43

CaO 2.07 2.31

Fe 2°3 10.34 0.00

SrO 0.40 0.45

Zr0

2

1.88 2.10

Mo0

3

1.97 1.96

Te0

2

0.28 0.31

Cs 2° 1.22 1.36

Ba0

2

0.59 0.66

Ce0

2

1.26 1.41

Cr2°3 0.44 0.00

NiO 0.21 0.00

P 2°5 0.51 0.57

U2°3 0.56 0.63

CdO 0.04 0.00

Nd

2°3

5.17 5.78

Pr

6°ll 0.56 0.63

Y2°3 0.23 0.25

56
TABLE 9. Physical properties of NBS K1620.

3

Density: 2828 gm/cm

Thermal Expansion Coefficient: 98.9 x 10 ^/°C (25-300 °C)

Annealing Point (ASTM C336): 539 °C

Refractive Index, N : 1.582

c Viscosity:

Temperature, °C Lofl.n

1305 1.099

1250 1.268

1200 1.422

1151 1.619

1101 1.816

1050 2.072

998 2.382

946 2.775

898 3.219

57
* TABLE 10. Leach rate measurements . MCC-1 test.

Deionized water, 90 °C, 14 days.

Normal i zed

Element

B

Si

Mo

Na

Cs

Sr

Ca

Ba

Zn

*Measurements courtesy of Materi

2 Elemental Mass Loss g/m

NBS R.M. 8400 PNL 76i

16.0 19.8

13.9 15.4

15.4 19.5

17.1 23.6

15.6 13.5

11.1 2.4

9.5 2.4

3.9 0.4

0.4 0.2

Characterization Center.

58
tests. Tests with Pyrex rods showed that differences in surface finish

can result in up to a factor of 4 difference in leach rate when using

this test. Weight loss was used as a measure of durability or leach

rate. Figure 21 shows representative data for experimental and commercial

glasses. The compositions of these glasses are given in table 11. No

MCC-1 data is available on these materials and no decisions have been

made as to the composition of RM8401.

D. Cronin, W. K. Haller

3. Leachability Measurements and Methods

a. Leachability Parameters, Importance and Control

The leachability of the nuclear waste form used to immobilize

high level waste is one of the most important characteristics of the waste

form. The reason for that is that leaching of the waste form by ground

water is thought to be the most probable way for radioactive waste to

re-enter the bisophere after immobilization. Thus designers of waste

forms develop waste types (i.e., ceramics, glasses, etc.) as well as specific formulations using leachability as a major performance criteria.

With this emphasis on the leachability of the nuclear waste forms, the

measurement of this property is of particular importance. The difficulty

of developing reliable tests and obtaining credible data is compounded by

the complexity of the leaching process. Leachability as it is currently

measured is totally dependent on the conditions and individual parameters

of the measurement system and has no intrinsic or absolute value. The

significance of each parameter of static leach tests has been under

investigation as part of the NBS Nuclear Waste Program. One of the

objects was to identify and evaluate the importance of each significant

parameter and then to understand its influence in the measurement of

leach rates. A summary of the significant parameters is listed in table

12. This list only includes the parameters specifically identified as affecting a static leach test, such as the first Materials Characterization

Center leach test (MCC-1). The number of parameters listed indicate the

difficulty of control of a speciation test such as aqueous leaching. The

dependence of the leach rates on each of the test conditions makes precise

control of each of the parameters essential in obtaining consistent

results. Further, while parameter control produces more precise results,

no means of judging accuracy is presently available.

The list of significant parameters controlling the leaching

characteristics can be greatly expanded when other types of leach tests

are considered. Some additional parameters are ground water composition,

host rock interactions and flow rate (in dynamic flowing leach tests).

Each new complexity investigated by the leach test introduces significantly more sophisticated parameter interactions and test control

difficulties. Some leach tests produce leachates which cannot be analyzed

by routine compositional analysis. Examples of these are the MCC 4 and 5

leach tests where high flow rates on durable waste forms produce volumes

of distilled water, brine, and silicate water leachates so diluted that

direct instrumental analysis is not feasible.

59
iCl

^8

\^/ r.

| ^ K+ L O Ci

Figure 21. Weight loss vs time using modified Soxhlet test.

60

Tl*\

t

*
TABLE 11. Glass compositions.

Corni ng

K1620 K1646 K1660 K1686 K1695 Float 7900

SiO

£

46.10 41.21 46.10 50.32 48.0 73.0 96.0

B2°3 10.96 9.80 10.96 - - - 3.0

Na

2

0 15.32 13.01 10.32 - 1.0 13.8 -

ZnO 5.75 5.14 5.75 - - - -

Ti0

2

3.43 5.07 3.43 - 3.5 - -

CaO 2.31 2.07 2.31 23.49 8.0 8.9 -

SrO 0.49 0.40 2.49 - 0.5 - -

Zr0

2

2.10 1.88 2.10 - - - -

Te0

2

0.31 0.28 0.31 - - - -

Cs

2

0 1.36 1.22 1.36 - 1.0 - -

BaO 0.66 0.59 0.66 - 5.0 - -

Ce0

2

1.41 1.26 1.41 - 0.5 - -

P 2°5 0.57 0.51 0.57 - - - -

Ca2°3 0.63 0.56 0.63 - - - -

Nd2°3 5.78 5.17 5.78 - 2.5 - -

Pr

6°ll

0.63 0.56 0.63 - - - -

Y 2°3 0.25 0.23 0.25 - - - -

m°0

3

1.96 1.97 1.96 - - - -

A1 2°3

- - 5.00 15.39 20.0 0.1 0.3

Fe2°3

- 10.34 - - -

0.

1

-

Cr2°3

- 0.44 - - - - -

NiO - 0.21 - - - - -

MgO - - - 10.79 5.0 3.9 -

CaF

2

- - - - 5.0 - -

so

3

- - - - - 0.2 -

61
TABLE 12. Parameters effecting leach test measurements.

Parameter Significance

Temperature 1 °C produces 5% to 15% variation in

leach rate and can control the leach

mechani sms pH Can totally control the leach mechanisms

CO

2

(dissolved from air)

HNO^ (residual from cleaning)

HF (residual from the teflon

contai ners)

Time

Eh

0^ (dissolved from air)

Surface area to volume ratio

Surface measurement

Surface preparation

Surface cleaning

Surface roughness

Composition

Homogeneity

Interference

Is quantifiable but not necessarily

representative

For distilled water Eh is controlled by

dissolved 0

^ content. Other leachate

systems are more complex.

Can cause X 2 to X 10 difference in

leach rate and 1-2 pH units

Can introduce additional leach mechanisms

Determines leach rate if all other parameters are constant.

Causes; congruent, incongruent, or can provide additional mechanism

Chemically perturb the test to produce

results as function of their chemical

effects

HN0

3

F

62
TABLE 12. (continued)

Parameter

Leachate Composition

Leach Vessel

Stability of Leachate

during leaching

post leaching

Mechanisms of Leaching

Analytical Instrumental

Significance

Must be a defined and consistently

available material.

Surface activity, chemical inertness

Directly influence results of analysis

of the leachant

Many are hypothesized at present. Both

removal and redeposition must be considered.

Analysis Leach rates are a function of the concen- tration determinations

63
The control of each of the most significant parameters as indicated presents specific problems. In addition to the control of

these individual parameters is the need to understand the complex synergistic effect the parameters have with one another. It is entirely

possible that rigorous control of the individual parameters without an understanding of the synergistic effects could produce precise results

that are not indicative of the long term performance of the nuclear waste

form in a repository.

In summary, these leach tests are in their developmental

stage and require significantly more effort to achieve the desired goal

of being representative of the behavior of a waste form in a geologicrepository. Obtaining precise measurement data from leach tests is the

first step toward understanding the mechanisms by which nuclear waste is

leached from a waste form. From this understanding, an accurate prediction

can be made of the long term behavior of the waste form in the repository.

H. Kingston

b. Leachate Test Evaluation

Evaluation of the repeatability and achievable precision

of the MCC-1 static leach test procedure was started using a series of

homogeneous glasses. The MCC-1 protocol was refined to eliminate two

potentially variable parameters consisting of dissolved C02 and 02 contained

in the leachate solution. The influence of these gases which dissolve in

the leach solution was eliminated by preparing the leach solution and

running the test under ascarite filtered Argon. The variability of the

surface finish of the glass was reduced by using 600 grit Silicon Carbide

to polish it after sawing. The temperature system was upgraded to maintain

control at 90.00° ± 0.04 °C. Temperature control is achieved by using a very well insulated and sealed water bath with a dedicated controller.

The instrument is monitored at five positions every three seconds and a tape and printed digital recording is updated every hour. The monitoring

system is power interrupt protected to detect power failures and thus

prevent unknown failures from influencing the leach results. Thirteen

different glass formulations were prepared for a statistically designed

experiment to determine independent relationships for the 9 priority

elements of interest. The variations in the compositions of the 13

glasses are listed in table 13. The basic composition of the glass was that of the NBS K1620 glass. The dimensioning of the cut and polished

glass ingots was done using a series of measurements to reduce surface area calculation errors. Using these measurements, the area was then

calculated using a series of equations to reduce the area estimation

error to below the specified limits of the MCC procedure. This study is

designed to provide an estimate of leach rate variations expected from a standard homogeneous glass. The study would also estimate Teachability rate

changes due to an inhomogeneous glass. In addition, it would provide information relating process compositional changes and their affect on the leach

rate. This study has a duration of several months, consequently, completion is

tentative pending availability of funds during FY 82.

H. Kingston, M. S. Epstein, W. Koch, D. Cronin

64
TABLE 13. Glass compositions (presented as variations from NBS K1620

glass) for the evaluation of the influence of heterogeneity and composition

on leaching.

is/Component

No.

Si B Na Ti Sr Mo Cs Ce Nd

1. 0 0 0 0 0 0 0 0 0

2. 10 -5 -5 0 0 0 0 0 0

3. 0 -5 5 0 0 0 0 0 0

4. - 5 5 0 0 0 0 0 0 0

5. 0 5 -5 0 0 0 0 0 0

6. -10 5 5 0 0 0 0 0 0

7. - 5 0 5 0 0 0 0 0 0

8. - 5 0 0 1 1 1 0 1 1

9. - 5 0 0 1 1 1 1 0 1

10. - 5 0 0 1 1 1 1 1 0

11. - 4 0 0 1 0 0 1 1 1

12. - 4 0 0 0 1 0 1 1 1

13. - 4 0 0 0 0 1 1 1 1

1 = increase from base glass of 1 wt percent

0 = no change

-1 = decrease from base glass of 1 wt percent

65
c. Leachate Stability Study

The stability of the final leachate solution is essential

to obtaining credible analytical composition analysis results upon which

to calculate the leach rates. The MCC-1 procedure dictates that a volume

of concentrated nitric acid be added to the leachate solution equal to 1

percent of the leachate volume after 28 days of leaching at a neutral or higher pH. This is done to stabilize the anionic and cationic species

and to redesolve any adsorbed ions from the container walls. The adsopriton

of ions onto plastic or glass container walls, thus changing the solution

concentration, is a well -documented phenomenon. The addition of acid to

prevent this process is also well -documented; however, the addition of

small quantities of acid to resolubilize previously adsorbed material has

not been thoroughly studied. In this investigation, NBS prepared glass

(K162Q) which was irradiated in the NBS reactor facility was then subjected

to leaching following the MCC-1 guidelines. After leaching, gamma counting

of containers and leachate solutions revealed that Cs and Sb did not

detectably adsorb onto the PFA Teflon containers over the 28 day test

periods. Zinc, however, was 27 percent adsorbed onto the container

walls. Subsequent addition of 1 percent nitric acid as specified in the

MCC-1 procedure totally removed the adsorbed Zn and resolubilized it

producing leachate containing 100 percent of the Zn removed from the

glass during the leaching period.

Other elements of importance which are likely to be adsorbed

during the leaching were unable to be detected due to the high gamma

field produced by the Cesium. Therefore, a special glass was prepared by

the NBS Glass Group having the same formulation minus the Cesium.

This glass will hopefully allow the observation of other important elements

and their adsorption and degree of resolubilization. This work remains

uncompleted at this time. The results thus far have verified both the

necessity and the effectiveness of the MCC-1 procedure for the elements

cesium, antimony and zinc. However, further tests of other elements

including the rare earth elements are necessary before complete conformation of the effectiveness of this portion of the test procedure is

assured.

G. Lutz and H. Kingston

d. Analytical Leachate Analysis

The D.C. plasma emission spectrometer has been modified

for the simultaneous determination of up to ten elements in the simulated

nuclear waste leachates. Detection limits in the multielement mode are

as follows (pg/ml):

B, ..01 Si

,

.03

Ba, .001 Sr, .0005

Ca, .0004 Ti, .01

Mo, .003 Zn, .02

Nd, .01 Ce, N.D.

66
The system has been designed to determine the above specialized

set of elements which have been designated as priority elements of interest

in nuclear waste leachate analysis.

M. S. Epstein, C. G. Blundell

C. Containers, Backfill, and Mathematical Support

This task is focused on the container and backfill material and

includes also the statistical and quality control effort for the whole

program.

In the area of containers, existing efforts to understand corrosion

mechanism were reviewed, and specific research was carried out in selected

areas to improve the understanding of degradation mechanisms of candidate

materials, particularly as they apply to long-term prediction and accelerated

testi ng.

Work on the backfill effort for the Nuclear Waste Program includes a review of existing efforts elsewhere, as well as developing specific

plans to perform selected research at NBS to improve the understanding of

the basic functional mechanisms (excluding sorption coefficient) related

to emplacement of backfill materials.

Extensive use of statistical services available at NBS was planned

for the effective use of the interlaboratory testing required in the

performance of these tasks.

1. Canister Corrosion

The technical activities related to canister corrosion were divided into four parts. The accomplishments during the past year in

each of these four parts were as follows:

a. Corrosion Mechanisms

This activity required a review of existing efforts and

research in selected areas as needed to improve the understanding of

degradation mechanisms of candidate materials, particularly as it applied

to long-term prediction and accelerated testing.

The second portion of this task required the setting up of

a research program aimed at improving the understanding of degradation

mechanisms and developing test methods. The following accomplishments

can be reported:

o An experimental approach was developed consisting of

three elements:

(1) Characterization of the environment that develops

in pits, cracks, and crevices under simulated

repository conditions.

67
(2) The carrying out of studies of electrochemical

corrosion mechanisms in the environments characterized in element "a" above.

(3) The use of mechanistic studies as a basis for

developing test methods to assess susceptibility

of alloys to localized corrosion.

o A laboratory was set up to carry out electrochemical

polarization studies and microanalytical characterization

of the localized environments. An autoclave is on order to carry out high temperature corrosion measurements.

o Work was started on the characterization of localized

environments, and the following results were obtained:

(1) Good results for Cl at the 5 to 10 pg level

using potentiometric titration and an Ag/Ag2 0

- Ag/Hg electrode pair.

(2) Techniques developed for removing 0.5 - 2 p£

aliquots of localized environments.

(3) Work in progress on microanalysis of other ions

such as Na

+

, etc.

(4) Spectrophotometric experiments involving Cl, Fe,

Cr, and Ti ions in the UV-VIS-NIR range started.

o Work on the electrochemistry of localized corrosion

has been started involving the following:

(1) Potentiodynamic polarization plots to determine

crevice and pitting susceptibilities and rates

at different temperatures.

(2) Cyclic polarization studies to determine critical

potential for pitting.

(3) Repassivation rate studies to assess susceptibi 1 ity.

(4) Crevice and pit chemistry study approach developed.

(5) Theoretical study on corrosion thermodynamics of

Ti-H2 0Cl systems started.

b. Research and Reference Materials and Definitive Test

Methods

This part of the task involves the development of a stock

of two or three different characterized research alloys for use in NBS

tests and as research materials for use by others.

68
Based on discussions with Sandia, a decision to stock T i

,

T1 CODE-12, and an austenitic stainless steel was made.

c. Key Data Generation and Evaluation

This effort requires cooperation with MCC in surveying and

evaluating existing data on underground corrosion of potential canister

materials. Our accomplishments have been the following:

(1) Collection data and literature from MCC, Sandia,

Bureau of Mines (Geothermal) and Oak Ridge.

(2) Bibliography on corrosion of metals in repository

environments completed.

(3) Completion of long-term (eight years) study of

stainless steels in underground environment

(sponsored by AISI) —available for distribution.

d. Long-Term Field Tests

This task requires the assessment of the feasibility of

long-term tests of container materials under geologic conditions. While

work on this task was not scheduled for this year, work on in situ polarization measurement techniques developed in other areas may prove applicable

to canister corrosion problems. This needs to be explored further.

J. Kruger, K. Hardman, B. T. Sanderson, J. Mullen, M. J. Rodriquez

2. Backfill

In the proposed underground scheme of nuclear waste management,

a multi-barrier isolation system is considered to contain the radionuclides

and thus to isolate them from reaching the biosphere over a long period

of time. As a simplified example, the multi-barrier system consists of a glass waste form, a metal container containing the waste form lowered

into a borehole drilled from the floor of tunnels in the repository,

backfill placed between the canister and borehole wall, and the repository

rock. The Geotechnical Engineering Group of CBT/NEL focused its efforts

on the study of the backfill component of the multi-barrier isolation

system.

The major item of our work is a state-of-the-art study on the

existing data, capabilities, and knowledge in selected areas as needed to

improve the understanding of the functional mechanisms such as hydraulic

conductivity, chemical physical, and mechanical stability, swelling

potential on wetting, and thermal conductivity of the backfill materials

when they are emplaced in a repository. To accomplish this task, the

following activities have been carried out: literature and data search,

communication with experts, and a two-day international workshop on backfi 1 1

.

69
The NBS Library computer data bases were utilized to locate

current publications pertinent to the backfill investigation. RECON,

which is the energy-related data base, appears to provide the best source

in locating publications specifically for the study of backfill functions

for nuclear waste management problems. Literature searches have also

included the areas of: (1) soil sciences, (2) highway and airfield engineering, and (3) cable industry. The first area, which includes journals

of clays and clay minerals, Soil Science Society of America, soil science,

irrigation and power, and water resources, provides information on hydraulic

conductivity under both saturated and unsaturated soil conditions. The

second area concerns the characteristics of soil swelling in pavement

design, how to identify the swelling potential, and the test method and

equipment to quantatively determine the magnitude of swelling and swelling

pressure. The cable industry provides many experimental results on the

soil thermal properties in conjunction with the heat generated from

buried transmission lines. Additionally, the damage to houses caused by

swelling of soils in many parts of the world challenged geotechnical

engineers for many years. Much work was done in trying to understand the

mechanisms of swelling and to develop construction methods which minimize

the magnitude of swelling.

A two-day workshop entitled, "Research and Development Needs in

Backfill for Nuclear Waste Storage in Deep Geologic Repositories," was held on April 13 and 14, 1981, at the NBS Campus. On the first day, ten

lectures were given by experts from national laboratories and private

industry in the States and from Canada and Sweden. Thirty-eight people

attended the first day presentation. On the second day, many of the

participants stayed on for an informal in-depth discussion on the subject.

Areas such as test materials, test methods, and test procedures used in

various laboratories for the evaluation of the backfill properties were

discussed. Summaries and conclusions of the Workshop will be included in

the Workshop report. The report is in preparation and is planned to be

published late in 1981. Workshop proceedings which include all the

papers presented to the Workshop are also in preparation.

Many material properties are desirable for the candidate materials

to be considered as backfill. These include sufficiently high swelling

potential and plasticity, low hydraulic conductivity, adequate thermal

conductivity, high sorption capability, adequate shear strength, and

chemical stability over a wide range of temperatures and pressures.

Candidate backfill materials include mixtures of bentonite, montmorillonite, zeolite, sand, crushed host rock, and additives for sorption of

selected radionuclides.

Our studies have been focused on three of the many cited pertinent

properties of the backfill. Those properties are swelling, hydraulic

conductivity, and thermal conductivity. Relative high magnitude of

swelling and plasticity of the backfill material is desirable to provide

a self-sealing ability for material cracks within the backfill and localized cracks and flaws in the surrounding rocks in order to minimize the

potential of groundwater intrusion. Backfill with low hydraulic conductivity,

70
when placed around the waste package, may shield the waste canister from

the intrusion of groundwater for a long time period and subsequently

inhibit mass movement of molecules and thereby minimize the corrosion

potential of the canister and delay leakage of radionuclides to the

groundwater.

The backfill will also be expected to conduct thermal energy

from the canisters to the host rock, thereby preventing excessive heating.

Consequently, assessment of the thermal conductivity of the backfill

surrounding the canisters is critical. Soils with high thermal resistance will not dissipate as rapidly away from the canister as soils with

a low thermal resistance.

It is the present consensus among the researchers in the field

that at least 10 percent of bentonite, or other types of clay minerals

should be included in the backfill. For backfill placed around the

canister, the clay content should be substantially higher. Thus, the

backfill will behave like a fine-grained soil.

The volume of a backfill will change with variations in external

pressure, temperature, and chemical environment. Changes in volume lead

to changes in material strength, subsequent deformation behavior, and

hydraulic conductivity. The swelling, and likewise compressibility of

the backfill, is a measure of its volume change characteristics and is

governed by the following factors: temperature, degree of saturation,

chemical cementation and organic bonding, particle shape, geometric

arrangement of particles, mechanical interactions, and physico-chemical

interactions. Since the hydraulic conductivity of the backfill changes

with the soil structure, the controlling factors for swelling should be

equally applicable in explaining the mechanisms of this property.

It is logical to assume that the smaller the particle size, the

smaller will be the void sizes of a soil. Since voids serve as flow

channels, smaller void sizes will yield a lower hydraulic conductivity

for a soil--all other variables remaining constant. In fact, a theoretical

model developed by Taylor using Poiseiulle's law showed that the hydraulic

conductivity varies in direct proportion to the square of a characteristic

particle diameter.

In the physico-chemical interaction, long range forces, such as the repulsive forces of the double layer and the van der Waal attractive

forces, are considered. Many research efforts have been directed toward

developing an understanding of the effect of physico-chemical interactions

on the swelling potential and hydraulic conductivity of clays. In summary,

the variables that control these interactions are particle shape, geometric

arrangement of particles, and clay chemistry.

Particles with large diameter-to-thickness ratios, such as those of bentonite, are subject to most favorable geometric conditions

for double layer interaction, and thus the physico-chemical effects are predominant. Chemical variables include surface charge density and

distribution, valency of the adsorbed cations, dielectric constant and

dipole moment of the pore fluid, and concentration of electrolyte in the

71
free pore fluid. It is understood that the existence of a net negative

charge on the surface of clay particles leads to the adsorption of cations.

A higher surface charge results in a stronger double layer effect. The

distribution of charges is also important; for instance, a kaolinite clay

with negative surface charge and positive edge charge will lead to flocculation rather than to dispersion under a low pH environment. A monovalent

cation can produce a thicker double layer than a divalent cation, thus

increasing the physico-chemical effect and resulting in a higher swelling

potential. Thicker double layers result in lower hydraulic conductivity

by reducing the effective opening of pores. Test results on Ca bentonite

indicated approximately 2 to 5 times higher hydraulic conductivity than

those on Na bentonite. The dielectric constant of the pore fluid is

important because only for fluids with high dielectric constants, such as water, is the degree to which adsorbed layers developed on the clay

particle surface significantly influenced. When the pore fluid is water,

its possession of dipole moment and high dielectric constant yield the

lowest value of hydraulic conductivity. The hydraulic conductivity is

higher for a polar fluid with a low dielectric constant, such as carbon

tetrachloride. The reason is that when fluids of low dielectric constant

are used as a permeant, the cations are held tightly against the clay

particle surface and thus the tendency of the double layer to block the

flow channels is minimized. Finally, when a nonpolar fluid is used, the

flow channels are almost completely open because of the inability of

cations or particle surfaces to adsorb fluid molecules. The thickness of

the double layer is influenced by the concentration of an electrolyte;

the lower the concentration, the thicker the double layer. The hydraulic

conductivity is also affected by the concentration of electrolyte; a reduction in concentration leads to a reduction in the value of the

hydraulic conductivity.

Examination of the literature reveals that information on the

factors affecting the thermal resistivity of soils can be found in a variety of technical fields. For example, references can be found in the areas of agronomy, soil mechanics, highway research, electric power

research and nuclear waste management. Each technical area has a list of

references that are often cited, but no list is comprehensive covering

all the information available in those fields in which the thermal properties

of soils are important.

The thermal resistivity of a soil is influenced primarily by

the following parameters:

o Soil composition

o Density

o Moisture content and degree of saturation

The relative importance of these factors is illustrated in

figure 22. Of particular interest is the Importance of soil moisture.

As moisture is added to the soil as a thin film around the soil particles,

a path for the flow of heat which bridges the air gaps between the solid

particles is provided. By increasing the effective contact areas between

72
THERMAL

RESISTIVITY

|nC

CM/WATT|

MOISTURE CONTENT M PERCENT

Figure 22. The effect of moisture content and dry density on the

thermal resistivity of soils (from Salomone and others,

1979).

73
particles, these films greatly reduce the thermal resistivity of the

soil. When the moisture condition in the soil approaches a wet condition,

the effective contact area no longer increases with increasing moisture

content. Consequently, the significant decrease in thermal resistivity

with increasing moisture content as the films around the solid particles

are forming is not evident when additional moisture is added to fill the

pore space. This trend is observed in figure 22.

Moisture migration is also an important consideration. The

moisture regime within the backfill barrier will be a function of two

driving forces: the porewater pressure gradients from the outer boundary

towards the canister and the thermal gradient from the inner boundary

toward the outer boundary. The thermal gradients existing in the backfill

can cause a redi stribution of moisture in the soil, thereby changing the

thermal resistivity of the soil. Because moisture migration under a thermal gradient involves capillary moisture, i.e., moisture in excess of

adsorbed (hygroscopic) water and which is held against the force of

gravity, the existing moisture content in the soil is an important con- sideration in deciding whether moisture migration is a problem.

We have identified problems with existing measurement techniques

related to the material properties, including hydraulic conductivity and

swelling. One important problem needs to be conveyed to DOE as soon as possible: The test variables of the compaction method, compaction effort,

and the amount of moisture content within the specimen at the time of

compaction were found by us to have a profound effect on the determination

of the values of both swelling potential and hydraulic conductivity. For

example, some references in the published literature indicate that the

values of hydraulic conductivity are so sensitive to these test variables

that they may change by as much as three orders of magnitude. The planned

MBS laboratory program was to determine these effects, so that reliable

measurements of anticipated performance can be made. With the NBS program

cancelled, somebody will have to do this work, so that no unpleasant

surprises are encountered when the backfill is installed.

An understanding of the factors affecting the thermal conductivity of soils leads us to conclude that:

o the thermal conductivity of the backfill material needs to

be evaluated for the design conditions,

o the available steady state and transient methods for

determining the thermal conductivity of soils should be

compared and the optimum approach determined, and

o concepts from the fields of agronomy and geotechnical

engineering and information on the heat transfer mechanisms

in soils should be combined to determine those index

properties of soils which correlate well with the thermal

properties of soils. Knowledge of these index properties

can be used to screen the backfill materials being considered

and to develop a classification system for purposes of

having a common language for researchers to document their

thermal conductivity test data.

74
Two papers have been prepared and submitted to conferences for

disseminating the information. One is an invited paper on the thermal

properties of soil materials which has been presented to a symposium

sponsored by EPRI and Ontario Hydro in September, 1981. The second one

is on reference laboratory testing for the determination of swelling and

hydraulic conductivity and has been accepted for presentation to the

Material Research Society's Annual Meeting in Boston, MA, November, 1981.

A state-of-the-art report is also in preparation. Much of the

information in the two papers mentioned above was generated from the

preparation work. However, with the sudden termination of this project,

we do not think we can incorporate the collected information into a comprehensive report since our efforts will have to reflect our funding

starting on October 1, 1981.

R. Chung, L. Salomone, F. Yokel

3. Development of Mathematical Methods

During FY 81, work was done on two mathematical techniques

which were intended for application not only in nuclear waste modeling,

but also in two additional areas of interest to NBS. The two techniques

are:

o A diagnostic tool for screening a rectangular array of

data such that a structure index can be computed to suggest

the presence or the absence of a random component in a mechanism model.

o A modeling tool involving the concept of a nested element

and the existence of a single-integral entropic functional.

J. Fong

75
Appendix A

Major Consulting and Advisory Services

J. W. Behrens advised the Oak Ridge National Laboratory on the

preparation of large fission deposits for the Clinch River Breeder Reactor

Program.

C. D. Bowman consulted with the Hanford Engineering Development

Laboratory on the nondestructive analysis of spent fuel from the FFTF.

C. D. Bowman advised the Electric Power Research Institute on the

nondestructive assay of spent power reactor fuel.

A. D. Carlson organized the national Department of Energy effort for

evaluation of measurements on neutron cross section standards.

J. Fong, et al .

,

advised DOE and NRC staffs on Modeling and Statistical

Design for Assessment of Waste Packages.

H. M. Kingston consultation on Teachability measurements and quality

control at Battel le. Battelle Richland, Washington, January 19-30, 1981.

W. F. Koch, G. Marinenko, D. Cronin, H. M. Kingston, Vitreous State

Labs of Catholic University on Teachability testing, June 16, 1981.

G. J. Lutz, consultation with Dr. L. Jardine at Argonne National

Laboratory on activation of nuclear waste glasses, November 13, 1980.

R. S. Roth advised Savannah River Laboratory on the chemical problems

associated with the development of a possible crystalline alternative to

glass, August 1981.

R. A. Schrack advised the Brookhaven National Laboratory Safeguards

staff on the nondestructive assay of spent commercial reactor fuel.

76
Appendix B

Commi ttee/Workshop Parti ci pati on

James W. Behrens - Member, DOE Cross Section Evaluation Working

Group (CSEWG), Standards Subcommittee; Member, Safeguards Committee,

Institute for Nuclear Materials Management.

Charles D. Bowman - Member, Department of Energy (DOE) Nuclear Data

Committee.

Allen D. Carlson - Member, DOE Cross Section Evaluation Working

Group (CSEWG), Standards Subcommittee.

B. Stephen Carpenter - Board of Directors, American Nuclear Society;

Member, Isotope and Radiations Division, Technical Committee for Nuclear

Safeguards; Member, Institute of Nuclear Materials Management Subcommittee

INMM-9.3 on Nondestructive Assay of Standards Committee N15 on Methods of

Nuclear Material Control; Member, Department of Energy, Office of Safeguards

and Security, Ad Hoc Task Group on Measurements and Standards.

Randall S. Caswell - Member, International Society of Radiology,

International Commission on Radiation Units and Measurements.

David A. Ditmars - Member, INMM 8.4, "Calibration Techniques in the

Calorimetric Assay of Pu-Bearing Solids"; Member, NBS Pu Steering Committee;

Member, ISPO Laboratory Coordinators Group.

John W. Gramlich - Member, Institute of Nuclear Materials Management

Committee N15,9.3, Nondestructive Assay - Physical Methods.

James A. Grundle - Member, ASTM E10.05, Committee on Neutron Dosimetry.

J. M. Robin Hutchinson - Chairman, International Committee of Radionuclide Metrology (ICRM), Subcommittee on Low-Level Techniques Group;

Member, American National Standards Institute (ANSI) Committee on Nuclear

Instruments and Detectors; Secretary, ANSI Subcommittee N42.2 on Procedural

Standards for Calibration of Detectors for Radioactive Measurements.

Harry H. Ku - serves on the Steering Committee of the Safeguards

Analytical Laboratory Evaluation Program.

J. Kruger - IWG of ONWI on Materials Degradation Mechanisms, participated in Materials Characterization Center Workshop on Test Procedures

for Corrosion of Engineered Barriers for Nuclear Waste Repositories.

James A. Lechner - Member of American Society for Testing and Materials (ASTM) Committee C26 on Nuclear Fuel Cycle, Chairman of Subcommittee

(26.06 on Statistical Methods; Member of ASTM Committee N15; advising the

Institute for Nuclear Materials Management Committee 9.4 on revised

standard for measurement control of NDA processes.

77
Walter Liggett - IAEA Advisory Group on Evaluation of Quality of

Safeguards NDA Measurement Data.

Lawrence A. Machlan - Member, Plutonium Steering Committee at MBS;

Member, ASTM C26 (Nuclear Fuel Cycle).

William P. Reed - Member of American Society for Testing and Materials

(ASTM) Committee C26 on the Nuclear Fuel Cycle. Member, ANSI N15 Nuclear

Standards, Member, INMM N15.9.3, USDOE Materials Characterization Organization Steering Committee.

R. S. Roth - participated in Materials Characterization Center

Workshop on the Compositional and Microstructural Analysis of Nuclear

Waste Materials.

S. J. Schneider - MCC Workshop on Test Procedures for Corrosion of

Engineered Barrier for Nuclear Waste Repositories; IWG of ONWI on Materials Degradation Mechanisms.

G. White - participated in Materials Characterization Center Workshop

on Radiation Effects.

78
Appendix C

Publ i cations

Behrens, J. W. , Schrack, R. A., and Bowman, C. D. , Nondestructive

Examination of a Defective Silver Braze Using Resonance-Neutron Radiography, Nuclear Technology, Vol. 51, No. 1, pp. 78-82, Nov. 1980.

Behrens, J. W. , Preparation of Accelerator Targets by Painting,

invited paper for 9th World Conf. of International Nuclear Target Development Society held at Gatl inburg, TN, October 12-16, 1980 (proceedings to

be published in Nuclear Instrum. Methods).

Bowman, C. D. , Efficient Neutron Production Using 12 MeV Electrons,

Proceedings of 1980 Conference on the Application of Accelerators in

Research and Industry held at North Texas State University, Denton,

Texas, Nov. 3-5, 1980, IEEE Transactions on Nuclear Science, pp. 1485-1487,

Vol. NS-28, #2, April 1981.

Bowman, C. D. and Johnson, R. G. , Measurements of Inelastic Scattering

of eV Neutrons (accepted for publication in proceedings of IPNS Symposium

on Neutron Scattering held at Argonne National Lab., Argonne, IL, August

12-14, 1981).

Fassett, J. D. and Kelly, W. R. , "Mass Spectrometric Analysis on Uranium and Plutonium Loaded Anion Exchange Resin Beads: An Interlaboratory Round Robin," Analytical Chemistry in Nuclear Technology, W. S. Lyon, ed. , (Proceedings of 25th Conference on Analytical Chemistry in

Energy Technology, Gatl inburg, TN, 1981), in preparation.

Johnson, R. G. and Bowman, C. D. , High Resolution Powder Diffraction

by White Source Transmission Measurements, (accepted for publication in

proceedings of IPNS Symposium on Neutron Scattering held at Argonne

National Lab. , Argonne, IL, August 12-14, 1981).

Johnson, R. G. , Behrens, J. W. , and Bowman, C. D. , Source Imaging

Using Neutron Pinhole Cameras Based on Position-Sensitive Proportional

Counters (accepted for publication in Nuclear Technology).

Jones, F. E. , Determination of Water in Solids by Automatic Karl

Fischer Titration, Analytical Chemistry 53, 1955-1956 (1981).

Jones, F. E. and Brickenkamp, C. S. , Calculation of Solvent-Water

Mixture Volumes, Analytical Chemistry 53, 362-363 (1981).

Jones, F. E. , Schoonover, R. M. , and Houser, J. F. , In-Tank Measurement of Solution Density, J. of Res., Natl. Bur. Stand. 85, 219-221

(1980).

Kopp, M. K. , Behrens, J. W. , Meacham, M. A., and Williams, J. A.,

Development of Proportional Counter Cameras for Neutron Imaging with 1 mm Resolution (to be published in Rev. Sci. Instrum.).

79
Kruger, J. and Hardman, V. K. , Current Understanding of Pitting and

Crevice Corrosion and Its Application to Test Methods for Determining

that Susceptibility to Such Corrosion of Nuclear Waste Containers (in

press)

.

Lechner, J. , Inventory Difference Calculations: Problems and Possibilities, NBSIR 81-2219.

Liggett, W. , Robust Inference for Items Measured a Few Times (draft

form).

Sanderson, B. T. and Kruger, J. , Bibliography on Corrosion of Metals

in Underground Repository Environments (in press).

Schleter, J. C. and Baloga, S. M. , Study of DOE Safeguards Measurement

Implementation Needs (draft form).

Schoonover, R. M. and Jones, F. E. , Air Buoyancy Correction in

High- Accuracy Weighing on Analytical Balances, Analytical Chemistry 53,

900-902 (1981).

Schrack, R. A., Behrens, J. W. , Johnson, R. G. , and Bowman, C. D.

,

Resonance Neutron Radiography Using an Electron Linac, Proceedings of the

Sixth Conference on the Application of Accelerators in Research and

Industry, held at North Texas State University, Denton, Texas, November

3-5, 1980. IEEE Transactions on Nuclear Science, Vol. NS-28, No. 2,

April 1981, pp. 1640-1643.

Spiegelman, C. , Some Conservative Statistical Approaches for Presenting Interlaboratory NDA Enrichment Measurements, NBSIR 81-222.

Spiegelman, C. , Lechner, J. , and Reeve, C. , A New Method of Assigning

Uncertainty in Volume Calibration, NBSIR 80-2151.

Spiegelman, C. , Sacks, J. , and Ylvisaker, D. , Nonparametric Calibration

(submitted to a technical journal).

Wasson, 0. A. and Meier, M. M. , Measurement of the 235 U Mass in a Large Volume Multiplated Fission Ionization Chamber (accepted for publication in Nuclear Instrum. Methods).

80
Appendix D

Talks

Bowman, C. D. , "Efficient Neutron Production Using 12 MeV Electrons,"

6th Conference on the Application of Accelerators in Research and Industry,

North Texas State University, Denton, TX, November 4, 1980.

Chung, R. C. , "Thermal Properties of Soil Materials," sponsored by

EPRI and Ontario Hydro, September 1981.

Chung, R. C. , "Reference Laboratory Testing for the Determination of

Swelling and Hydraulic Conductivity," Material Research Society, Boston,

MA, November 1981.

Epstein, M. S. , "Review of Analytical Methods for Liquids and Solutions

at NBS," Workshop on Compositional and Microstructural Analysis of Nuclear

Waste Materials, Battelle Research Center, Seattle, WA, November 11, 1980.

Epstein, M. S. , "Analysis of Nuclear Waste Leachates for Trace

Elements by Atomic Spectroscopy: Problems and Solutions," 8th Annual

Meeting of the Federation of Analytical Chemistry and Spectroscopy Societies, Philadelphia, PA, September 23, 1981.

Fassett, J. D. , Kelly, W. R. , and Machlan, L. A., "Mass Spectrometric

Analysis of Nanogram Levels of Plutonium," 24th Conference on Analytical

Chemistry in Energy Technology, Gatlinburg, TN, October 7, 1980.

Fassett, J. D. and Kelly, W. R. , "The Mass Spectrometric Analysis on Uranium and Plutonium Loaded Anion Exchange Resin Beads: An Interlaboratory Round Robin," 25th Conference on Analytical Chemistry in Energy

Technology, Gatlinburg, TN, October 7, 1981.

Fong, J. T. "Mathematical Modeling Support for NBS Nuclear Waste

Project," NBS Technical Staff Meeting, February 24, 1981.

Fong, J. T. , "Some Applications of Mathematics in Materials Science:

Before and After," Johns Hopkins University, Baltimore, MD, March 4, 1981.

Fong, J. T. , "On Upgrading the Mathematics Requirements of Mechanics

and Materials Science Majors," Lehigh University, Bethlehem, PA, September 11, 1981.

Kelly, W. R. and Fassett, J. D. , "The Determination of Subnanogram

Quantities of Uranium by Isotope Dilution Mass Spectrometry," 29th Annual

Conference on Mass Spectrometry and Allied Topics, Minneapolis, MN,

May 27, 1981.

Kingston, H. M. , "State-of-the-Art Analytical Measurements of Trace

Elements in Aqueous and Other Matrices with an Emphasis on Chemical

Manipulation," Rockwell International Labs, Richland, WA, January 27, 1981.

81
Kingston, H. M. , "Trace Metal Analysis: The Effects of Chemical Manipulation on the Results," Battel le Pacific Northwest Labs, Richland, WA,

January 28, 1981.

Kingston, H. M. , "The Analytical Constraints that Influence Leach Measurements and Reference Materials," 8th Annual Meeting of the Federation of

Analytical Chemistry and Spectroscopy Societies, Philadelphia, PA, September 23, 1981.

Lutz, G. J. , "The Analysis of Solids," Workshop on Compositional and

Microstructural Analysis of Nuclear Waste Materials," Battelle Research

Center, Seattle, WA, November 11, 1980.

Moody, J. R. , "Some Considerations of Analytical Methodology Relevant to

Radioactive Solid Leachate Testing," ORNL Conference on the Leachability

of Radioactive Solids, Gatl inburg, TN, December 10, 1980.

Reed, W. P. , "Measurements and Standards for Nuclear Waste Management"

Eighth Annual FACSS Meeting, Philadelphia, PA, September 23, 1981.

Roth, R. S. , "Phase and Microstructure Analysis" at MCC Workshop on Compositional and Micro Structural Analysis of Nuclear Waste Materials.

Roth, R. S. , "Crystallography Concerning Some of the BaO-Containing

Phases in Our Current Nuclear Waste Studies," 12th Congress of the International Union of Crystallography.

Roth, R. S. , "Crystallography Concerning Some of the BaO-Containing

Phases in Our Current Nuclear Waste Studies," Grenoble, France.

Roth, R. S. , "Crystallography Concerning Some of the BaO-Containing

Phases in Our Current Nuclear Waste Studies," Ljubljana, Yugoslavia.

Schrack, R. A. , "Resonance Neutron Radiography Using an Electron Linac,"

6th Conference on the Application of Accelerators in Research and Industry,

North Texas State University, Denton, TX, November 4, 1980.

82
Appendix E

Organized Symposia and Workshops

Chung, R. C. , "Research and Development Needs in Backfill for Nuclear

Waste Storage in Deep Geologic Repositories," two-day conference held at

NBS on April 13-14, 1981.

Magnani, N. , Sandia Laboratory, "Sandias Canister Corrosion Activities,

at NBS, February 9, 1981.

Nelson, R. , Pacific Northwest Laboratory and Steindler, M. , Argonne

National Laboratory, "The Role of the Material Characterization Organization in High Level Nuclear Waste Management," at NBS, May 14, 1981.

Pearlman, H. , Energy Systems Group, Rockwell International, Canoga

Park, CA, "Effects of Radiation on Tailored Ceramic High Level Waste

Forms," at NBS, June 15, 1981.

Reed, W. P. and Kingston, H. S. , "The Analytical Chemistry of the

Nuclear Waste Form." Held at the 8th Annual FACSS Meeting in Philadelphia,

PA, September 23, 1981.

Yolken, H. T. , "Methods Used to Measure Leachability and Present

Data." Held at ORNL Conference on the Leachability of Radioactive Solid,

Gatl inburg, TN, December 10, 1980.

83
Appendix F

Functional Statements

NATIONAL MEASUREMENT LABORATORY

Provides the national system of physical and chemical and materials

measurement; coordinates the system with measurement systems of other

nations, and furnishes essential services leading to accurate and uniform

physical and chemical measurement throughout the Nation's scientific

community, industry, and commerce; conducts materials research leading to

improved methods of measurement, standards, and data on the properties of

materials needed by industry, commerce, educational institutions, and

government; provides advisory and research services to other government

agencies; conducts physical and chemical research; develops, produces,

and distributes standard reference materials; provides standard reference

data; provides calibration services; and collaborates with the Bureau's

major organizational units in carrying out its responsibilities.

OFFICE OF MEASUREMENTS FOR NUCLEAR TECHNOLOGY

Provides the Nation with needed measurement standards and services

for nuclear technology in the areas of nuclear waste management and

safeguarding nuclear materials; plans, directs, and coordinates the

Program's laboratory work that is carried out within NBS units; and

disseminates these standards and services domestically and to other

nations and to international organzations.

84
Appendix G

85
Appendix H

86
Appendix I

BUDGET

Office of Measurements for Nuclear Technology

Sponsor Program

NRC Nuclear Safeguards $ 13,000

DOE Nuclear Safeguards 933,600

ISPO Nuclear Safeguards 127,700

DOE Nuclear Waste 1,105,000

DOE Nuclear Waste Equipment

Including Carry-Over 125,000

TOTAL $2,304,300

BY CENTER

Nuclear Waste Nuclear Safeguards

Reactor Services $ 9,000 $ 5,000

OMNT 92,800 99,100

CRR — 320,200

CCP 53,000 65,000

CAC 199,500 343,300

CMS 676,000 20,000

CAM 50,300 75,000

CBT 149,400 --

CCE -- 144,700

TOTAL $1,230,000 $1,074,300

87

NBS-114A IREV. 2-80

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT NO.

NBSIR 81-2441

2. Performing Organ. Report No. 3. Ptibl ication Dace January 1982

4. TITLE AND SUBTITLE

Office of Measurements for Nuclear Technology

5. AUTHOR(S)

W. P. Reed and H. T. Yolken

6. PERFORMING ORGANIZATION (If joint or other than NBS, see in struction s) 7. Contract/Grant No.

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE 3. Type of Report & Period Coverea

WASHINGTON, D.C. 20234 Office Annual Report

Fiscal Year 1981

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS ( Street . City. State. ZIP)

National Bureau of Standards

10. SUPPLEMENTARY NOTES

T Document describes a computer program; SF-185, FlPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here)

This annual report is a summary of the National Bureau of Standards (NBS)

Measurements for Nuclear Technology (MNT) Program for Fiscal Year 1981. The

MNT activities at NBS are divided into two programs : Nuclear Safeguards and

Nuclear Waste Management.

The MNT Program is one of several matrix managed efforts at NBS. The programs

provide a focus for the activity, both inside and outside NBS. The programs

provide funds and directions for needed technical work that is done within

NBS Centers. People remain attached to Centers but are funded for specific

activities in a matrix management approach. A program provides central

organization for outside inquiries and for distribution of results. Often

programmatic focus can provide improved assistance to outside agencies with

measurement problems. The MNT Program is operating in this manner.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

accountability guide; bulk measurements; isotopic assay; leachability studies;

nondestructive assay; nuclear safeguards; nuclear waste management; Standard

Reference Materials; statistical evaluation

13. AVAILABILITY 14. NO. OF

PRINTED PAGES

Unlimited -

j~X~i For Official Distribution. Do Not Release to NTIS

! Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402. 15. Price

i ] Order From National Technical Information Service (NTIS), Springfield, VA. 22161

USCOMM-OC 6043-P 30


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