# A dynamic error analysis of vapor fraction measurements using neutron radiography

## Abstract

A video-image analysis technique has been developed to extract average vapor fractions from real-time videotaped neutron attenuation. This consists of measuring the gray-level distribution throughout the flow region illuminated by the thermal neutron beam. In real-time video images, liquid regions appear dark (high neutron removal), and vapor appears light. It is a common practice to average the time-dependent brightness information (gray-level data) and then process this information to produce a spatial distribution of time-averaged vapor fraction over the conduit. Such a time-averaging technique can cause an error (dynamic error) that is related to fluctuations in the local density of the two-phase fluid. It results from the fact that the logarithm of the time-averaged intensity of the transmitted neutron beam (count-mode measure) is not equal to the time-averaged value of the logarithm of the intensity of the beam that is considered to be exact (exact measure). An analysis of the dynamic error was conducted to quantify the maximum errors achievable in the neutron radiography technique developed for vapor fraction measurements.

- Authors:

- Bettis Atomic Power Lab., West Mifflin, PA (United States)

- Publication Date:

- OSTI Identifier:
- 678132

- Report Number(s):
- CONF-990605-

Journal ID: TANSAO; ISSN 0003-018X; TRN: 99:009117

- Resource Type:
- Journal Article

- Journal Name:
- Transactions of the American Nuclear Society

- Additional Journal Information:
- Journal Volume: 80; Conference: 1999 annual meeting of the American Nuclear Society (ANS), Boston, MA (United States), 6-10 Jun 1999; Other Information: PBD: 1999

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; TWO-PHASE FLOW; VOID FRACTION; REAL TIME SYSTEMS; NEUTRON RADIOGRAPHY; FLOW VISUALIZATION; ERRORS

### Citation Formats

```
Joo, H., and Glickstein, S.S.
```*A dynamic error analysis of vapor fraction measurements using neutron radiography*. United States: N. p., 1999.
Web.

```
Joo, H., & Glickstein, S.S.
```*A dynamic error analysis of vapor fraction measurements using neutron radiography*. United States.

```
Joo, H., and Glickstein, S.S. Wed .
"A dynamic error analysis of vapor fraction measurements using neutron radiography". United States.
```

```
@article{osti_678132,
```

title = {A dynamic error analysis of vapor fraction measurements using neutron radiography},

author = {Joo, H. and Glickstein, S.S.},

abstractNote = {A video-image analysis technique has been developed to extract average vapor fractions from real-time videotaped neutron attenuation. This consists of measuring the gray-level distribution throughout the flow region illuminated by the thermal neutron beam. In real-time video images, liquid regions appear dark (high neutron removal), and vapor appears light. It is a common practice to average the time-dependent brightness information (gray-level data) and then process this information to produce a spatial distribution of time-averaged vapor fraction over the conduit. Such a time-averaging technique can cause an error (dynamic error) that is related to fluctuations in the local density of the two-phase fluid. It results from the fact that the logarithm of the time-averaged intensity of the transmitted neutron beam (count-mode measure) is not equal to the time-averaged value of the logarithm of the intensity of the beam that is considered to be exact (exact measure). An analysis of the dynamic error was conducted to quantify the maximum errors achievable in the neutron radiography technique developed for vapor fraction measurements.},

doi = {},

journal = {Transactions of the American Nuclear Society},

number = ,

volume = 80,

place = {United States},

year = {1999},

month = {9}

}