FPA-395_01 : PROPOSALS
Dear dieter, here after the first draft proposal for FPA-395_02. This is mainly a list
of proposals to be discussed and agreed.
1) AGH :
ITER steel material were irradiated in 6Li 14MeV converter in Maria reactor.
Samples were so active that some of them are going to be measured from now on.
AGH manages to get SANDII unfolding code to better assess neutron spectrum in converter
with the use of measured activation foils.
AGH proposal is a detailed analysis of ITER materials activation, details to be further discussed
2) NPI :
To continue the work on the gas production cross-section on further EUROFER
components (we are considering W, Ta, Mn, V, C).
A recent contribution by KIT (Analyses of shielding benchmark experiments
using FENDL-3 cross-section data starter library for ITER and IFMIF
applications, by Keitaro Kondo, Ulrich Fischer, Pavel Pereslavtsev and Arkady
Serikov) made us NPI consider about TIARA-like transmission experiments at
our energies (20-35MeV) with the focus on the O-16, (we wonder whether this
last activity fits better to SINBAD related work)
3) KIT :
To include, as far as feasible, another neutron transport benchmark
experiment in the next grant.
Proposed options:
1. A benchmark experiment on a pure Cr assembly. We discussed such a
proposal previously (even "pre-GRT-395") but discarded it finally because of
too high material costs of Cr. The arguments in support of such an
experiment are still valid. Other things are changing - sometimes rapidly.
Maybe it is feasible now ?
2. Utilize the materials that you already have available (Cu, W, ...) for a
somewhat "design-oriented" experiment revealing new features/characteristics.
Option 2.1: W/Cu experiment: This would be related to the divertor target
(W: armour, Cu: heat sink). The layers should then be very thin - not really
good for a neutron transport benchmark experiment. On the other hand, the
W/Cu layer could be backed by a steel assembly (representing to some extent:
divertor cassette, shielding material). This would affect the spectrum in
both the W and the Cu layer. Would be worth to check experimentally. (The
impinging neutron source spectrum should be shaped with a source reflector
like you applied it in some other experiment).
Option 2.2: W/PE experiment (PE/perspex as solid surrogate of water). W mixed
with an efficient neutron moderator (like water or PE) is one of the best
shielding materials. Such a solution might be used in a power/DEMO reactor.
The PE, arranged in layers between the W layers, would provide a very soft
neutron spectrum which will extend over the W resonance range down to,
possibly, thermal energies- if the assembly is thick enough and sufficient
neutrons can survive the resonance captures. The spectrum should actually
change quite rapidly from the front to the back. Would be very interesting to
see if we can predict the spectrum (and responses in W) with sufficient
accuracy !
NOTE: Ulrich would favour Option-2.2 since such an experiment looks very
interesting and is really missing.
4) JSI :
1- Jointly with AGH: As the follow-up of the previous activity, JSI is
proposing the detailed analysis of the TLD measurements performed in TRIGA
last year. As
reported the TLDs provided by Władysław Pohorecki were measured in
addition to the Mn and Au foils planned in the action. Corrections
specific to the irradiation of TLDs (flux perturbation due to a large
amount of Cd and glass, accounting of impurities in glass, detailed
irradiation history etc) have to be evaluated to allow a proper comparison
and judge the consistency between the T measurements by TLD and
estimations based on Mn foil irradiations.
The main objective is the analysis and interpretation of the TLD measurements
performed on a voluntary bases and investigate the consistency between the Mn
and TLD results.
2- As in the past JSI could participate with the sensitivity/uncertainty
pre-analysis in the preparation or selection of benchmark configurations and
post-analysis.
Ivo, thinks that shielding materials involving O and W (& Cr if
feasible), as proposed by KIT and ENEA would be of interest.
3. (Re-)evaluation of benchmarks in SINBAD, both those already included
and/or new benchmarks, such as
FNG-HCLL and Rez benchmarks.
KIT
KIT proposals for further discussion:
1.) Measurement of fast neutron and gamma ray spectra in the assemblies
Ulrich proposed (where suitable. The available detector has a size of 1.5" x
1.5").
2.) Continue to study, development and test of self-powered neutron
detector(s) (SPND) for the neutron flux monitoring inside the ITER TBM. This
will be achieved by means of the construction and test of a prototype of a
new SPND more suitable to operate in a TBM neutron flux spectrum. The
selection of this new SPND represents the output of the previous grant GRT-56
and FPA-395-SG-1.
3) Neutronics-related work for a TBM-NAS such as particular rabbit
design/composition and irradiation tests
4) Study of SiC detectors suitable to operate and to withstand high
temperature fields such as those expected in ITER. Particular focus would be
on cabling and processing electronics. Tests with 14 MeV neutron irradiation
with the detector heated at high temperature will be performed. This activity
depends on the availability of already manufactured SiC diodes (production of
new SiC diodes is most likely not possible with the usual funding)
ENEA
1 - New neutronics experiment
a) design oriented mock-up experiment on divertor using real ITER monoblocks,
b) “water activation experiment” by developing a similar system as in
JAEA/FNS experiment with water loop /active gamma spectrometer and shield but
properly designed to verify and evaluate the uncertainty on the estimation of
the prediction of ITER dose level in port cell due to water activation.
We also supports KIT proposals (especially 2.2).
However the question of costs is crucial as the ENEA financial situation do
not allow us to spend too much money. We started an internal check to verify
which materials are available (e.g. tungsten) and which should be the cost
for a new experiment in support of divertor studies. We hope to have more
data and a more clear vision at the next Paris Meeting.
Of course we are interest to all the phases of the new experiment, from its
design to irradiation and measurements at FNG including pre and post
analysis.
2- We propose the continuation of the effort related to the development of
diamond detectors in view of their installation at JET during the DT campaign
in 2018. This is the continuation of present effort, in particular we need to
concentrate on the development of proper electronics and the assessment of
present design so to improve the present results as well as study the problem
of calibrating the detector for on-line tritium measurement.
3- SPND : in collaboration with KIT we plan to study the Be-emitter SPND and
to complete further studies on the Cr emitter SPND (some discussions are
ongoing with ISIS and ILL lab. to see whether it could be possible to test
these detectors at high neutron fluxes). Tests for diamond detectors are
considered too.
4- We propose the development and validation of special nuclear data library
for Direct one step method based on FENDL-3 for shutdown dose rate
calculations in ITER (in collaboration with L. Petrizzi , EC)