Title: Distributed Fiber Sensors With High Spatial Resolution in Extreme Radiation Environments in Nuclear Reactor Cores

Abstract

This paper is a comprehensive experimental report on the neutron radiation effects of distributed optical fiber sensors with enhanced Rayleigh scattering profiles in an in-pile environment. Femtosecond laser direct writing was used to inscribe Type-II modifications in standard telecom fibers and radiation-hardened fibers with fluorine-doped cores. Rayleigh backscattering signals were enhanced for continuous 1.5 m. In-pile lead-out sensors tests were carried out at the MIT Research Reactor for two months, which was operated at a nominal power of 5.7 MW with fast neutron (>0.1 MeV) flux of 1.29 × 1014 n/cm2/s and an in-core temperature of up to 560°C. Using the Optical Frequency Domain Reflectometry technique, the backscattering profiles of fiber sensors were interrogated with a 3-cm spatial resolution to monitor the temperature profile of the reactor. Results show that laser inscribed Type-II modifications in the form of nanogratings are highly stable against extreme temperature and ionizing radiation. Both standard telecom fibers and radiation-hardened fibers with laser-enhanced Rayleigh profiles can continuously perform distributed temperature measurements over the entire duration of the in-pile testing. Temperature coefficients of sensors and spectral shift quality were studied as functions of total radiation fluence. To the best of our knowledge, we present for the firstmore » time, the temperature profile of an operating nuclear reactor core with 3-cm spatial resolution, enabled by distributed fiber sensors with laser-enhanced Rayleigh scattering profiles. The high spatial resolution measurements can provide valuable data for the design and validation of digital twin and virtual reality of nuclear energy systems.« less

Authors:

Wu, Jingyu  ^[1];

• Search DOE PAGES for author "Wu, Jingyu"
• Search DOE PAGES for ORCID "0000-0003-3599-6568"

Wang, Mohan  ^[1];

• Search DOE PAGES for author "Wang, Mohan"
• Search DOE PAGES for ORCID "0000-0001-6678-4993"

Zhao, Kehao ^[1]; Huang, Sheng ^[1]; Zaghloul, Mohamed ^[1]; Cao, Rongtao ^[1]; Carpenter, David ^[2]; Zheng, Guiqiu  ^[2];

• Search DOE PAGES for author "Zheng, Guiqiu"
• Search DOE PAGES for ORCID "0000-0002-5783-5848"

Rountree, Steven Derek  ^[3];

• Search DOE PAGES for author "Rountree, Steven Derek"
• Search DOE PAGES for ORCID "0000-0002-2151-3556"

Chen, K. P.  ^[1]

• Search DOE PAGES for author "Chen, K. P."
• Search DOE PAGES for ORCID "0000-0003-1595-4475"

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+ Show Author Affiliations

1. Univ. of Pittsburgh, PA (United States)
2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
3. Luna Innovations, Blacksburg, VA (United States)

Publication Date:

Thu Jul 01 00:00:00 EDT 2021

Research Org.:

Luna Innovations Incorporated, Blacksburg, VA (United States); Univ. of Pittsburgh, PA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1832117

Grant/Contract Number:  

SC0017826; NE0008686; FE0031570; FE0031175

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Lightwave Technology

Additional Journal Information:

Journal Volume: 39; Journal Issue: 14; Journal ID: ISSN 0733-8724

Publisher:

IEEE

Country of Publication:

United States

Language:

English

Subject:

22 GENERAL STUDIES OF NUCLEAR REACTORS; High-temperature; neutron radiation effects; optical fiber sensors; reflectometr; temperature measurement.