ML19114A326
| ML19114A326 | |
| Person / Time | |
|---|---|
| Site: | 07103052 |
| Issue date: | 03/05/2019 |
| From: | Azzaoui S TN Americas LLC, Orano USA |
| To: | Division of Spent Fuel Management |
| Shared Package | |
| ML19115A128 | List:
|
| References | |
| DOS-18-011415-045-NPV, V1.0 | |
| Download: ML19114A326 (17) | |
Text
NON PROPRIETARY VERSION Form: PM04-4-MO-6 rev.02 Orano TN SAFETY ANALYSIS REPORT N O N P RO P R I ET AR Y V E R S I ON CHAPTER 4A - APPENDIX 14 Prepared by / signature Date TN-MTR S.AZZAOUI Identification:
DOS-18-011415-045 Version:
1.0 Page 1 / 17 TN International Evaluation of equivalent dose rates around the TN-MTR cask loaded with the gisete content and its internal fittings Table of Contents Revisions / versions history 2
Summary 3
- 1. Purpose 4
- 2. Description of the TN-MTR cask and its content 4
- 3. Acceptance criteria 5
- 4. Demonstration of compliance with regulatory criteria in normal conditions of transport 5
- 5. Equivalent dose rate calculation in routine and accident conditions of transport 6
- 6. Conclusion 9
- 7. References 9
List of tables 11 List of figures 12
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 2 of 17 NON PROPRIETARY VERSION Revisions / versions history Rev. or Version Date Purpose and record of changes Prepared by / Checked by 1.0 See page 1 First issue S. AZZAOUI / T.WILLEMS/
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 3 of 17 NON PROPRIETARY VERSION Summary The purpose of this study is to ensure that the regulatory criteria for dose equivalent rates are respected:
in routine conditions of transport; in normal conditions of transport; in accident conditions of transport, of the TN-MTR cask equipped with a standard type lid, loaded with the gisete content and its internal fittings.
The gisete content consists of an isotope generator, made up of a source block containing the radioactive materials and a body equipped with a closure system around this block, placed in its internal fitting. The radioactive material consists of a strontium 90 titanium source (SrTiO3) with a maximum activity level equal to 897 TBq.
The TN-MTR cask containing the gisete content respects regulatory criteria for dose equivalent rates in routine transport conditions and accident transport conditions with the following maximum values:
DER (mSv.h-1)
Criterion (mSv.h-1)
RCT - Contact 2.94x10-2 2
RCT - 2 metres 3.69x10-4 ACT - 1 metre 2.07 10 In normal conditions of transport, the integrity of the internal fittings that hold the content in position and the limited damage to the package resulting from regulatory tests for normal conditions of transport guarantee compliance with the criterion for an increase in radiation intensity less than 20%.
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 4 of 17 NON PROPRIETARY VERSION
- 1.
Purpose The purpose of this study is to ensure that the regulatory criteria for dose equivalent rates are respected:
in Routine Conditions of Transport (RCT);
in Normal Conditions of Transport (NCT);
in Accident Conditions of Transport (ACT):
of the TN-MTR cask equipped with a standard type lid, loaded with the gisete content and its internal fittings.
- 2.
Description of the TN-MTR cask and its content The TN-MTR cask is loaded with the gisete content and its internal fittings.
2.1. TN-MTR Cask The TN-MTR cask, described in Chapter 0, is generally cylindrical in shape and its principal dimensions are 1,480 mm outside diameter (not including fins), 960 mm inside diameter and 2,008 mm effective height.
The radial shielding is composed of the following, from the inside to the outside:
20 mm of steel; of lead; of resin; 25 mm of stainless steel.
The axial bottom shielding is composed of the following, from the inside to the outside:
30 mm of steel; of lead; of resin; 25 mm of stainless steel.
The axial shielding at the top is composed of the standard lid and the shock absorbing cover.
The lid comprises, from the inside to the outside:
35 mm of steel; of lead; 65 mm of stainless steel.
The shock absorbing cover is composed of steel and wood with a total thickness in the central part equal to:
24 mm of stainless steel; 166 mm of wood.
The chemical composition of the materials used in the structure as taken from Chapter 0 are summarised in 4A-14.1.
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 5 of 17 NON PROPRIETARY VERSION 2.2. Description of the gisete internal fittings The gisete internal fittings are described in chapter 0A-14. There are 3 types of internal fittings which all consist of 2 parts:
a radial wedge that can be equipped with a bottom; an axial wedge.
The axial wedge of the 3 types of fitting is equipped with an upper aluminium disc with a minimum thickness of 60 mm The internal fittings wedge the gisete content radially and axially in the cask cavity.
2.3. Description of the gisete content The gisete content described in Chapter 0A-14 consists of an isotope generator. There are three possible types of isotope generator: gisete 4, gisete 5 and gisete 8.
The main components of the 3 types of isotope generator are a source block containing the radioactive material and a body equipped with a closure system around this block.
The properties of the radioactive material presented in Chapter 0A-14 are as follows:
The radioactive material consists of a strontium 90 titanium source (SrTiO3), in the form of sintered pellets, placed in a metal capsule, and forming the source block; the activity of the isotopes contained in the gisete must correspond to the following maximum activity levels:
Isotope
- Max. activities (TBq) 90Sr 897
- Any other isotope is authorised provided its activity is below the activity limit corresponding to an exempted consignment.
- 3.
Acceptance criteria The regulatory dose equivalent rate limits (DER) [1] are the following:
Routine conditions of transport (RCT):
the maximum DER in contact with the package shall be less than 2 mSv/h; Normal Conditions of Transport (NCT):
the increase in the DER over the entire outside surface of the package following the regulatory tests representative of normal conditions of transport shall be less than 20 %.
Accident Conditions of Transport (ACT):
the maximum DER at 1 m from the package shall be less than 10 mSv/h.
- 4.
Demonstration of compliance with regulatory criteria in normal conditions of transport The internal fittings ensure the gisete content is positioned in the TN-MTR cask cavity with reduced gaps, thereby limiting possible isotope generator shifting in the cavity. The mechanical strength of the internal fittings components under the loads imposed by normal conditions of transport is
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 6 of 17 NON PROPRIETARY VERSION demonstrated in Chapter 1A-14. It is therefore guaranteed that the isotope generator will be held in position in the internal fittings.
In addition, Chapter 4A demonstrates that crushing of the shock absorbing cover as a result of regulatory tests under normal conditions of transport does not cause an increase in the maximum dose equivalent rate of more than 20%.
Therefore, the criterion requiring an increase in radiation intensity less than 20% in normal conditions of transport compared to routine conditions of transport is fulfilled.
- 5.
Equivalent dose rate calculation in routine and accident conditions of transport 5.1.
Computer codes used Source calculations are made using the ORIGEN-ARP program (SCALE6 system) [2].
Dose equivalent rates are evaluated using the TRIPOLI 4 program version 4 [3]. The program solves the equation for particle transport in a three-dimensional geometry using the Monte Carlo method. The ENDF/B-VI library is used for cross-sections.
5.2. Geometrical model 5.2.1. Hypotheses concerning the cask The following conservative assumptions are made for the cask:
cooling fins are not modelled and wood and lead densities are set at their minimum values, i.e. 0.1 and 11 respectively so as to minimise shielding, in accordance with Chapter 0.
the lid is provided with two stainless steel orifices through which a conduit passes.
The density of the orifices was reduced to take them into account (see Appendix 2 of Chapter 4A).
The height of lead on the cavity side (at the lead shoulder) is 5 mm more than on the outside. It is conservatively assumed to be equal to the height of lead on the outside; the shock absorbing cover is modelled as intact.
The calculation model in RCT is presented in Figure 4A-14.1.
Specific conservative assumptions in ACT are as follows:
the shock absorbing cover is not modelled; the resin is replaced by air; lead slumping equal to 37 mm is taken into account; the lead thickness has been reduced by 4 mm on the inside face of the lead shoulder and by 15 mm on the inside face of other parts of the cavity.
The calculation model in ACT is presented in Figure 4A-14.2.
5.2.2. Assumptions about the content Assumptions specific to the content are as follows:
In routine conditions of transport, the shielding provided by the internal fittings is not taken into account;
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 7 of 17 NON PROPRIETARY VERSION in accident conditions of transport, the radial wedge is considered to be completely failed; only the upper disc of the axial wedge is taken into account for the source position; Conservatively, the radiological protection provided by the isotope generator body is not taken into account; only the radioactive material is taken into account and modelled by a point source; the density of the source is considered equal to air density so that self-shielding of the source is not taken into account; the source is a 90Sr source with activity equal to 897 TBq, cooled for 30 days to reach its secular equilibrium; The source is considered as a pure primary gamma emitter; the radioactive source is not fissile; therefore the dry effective multiplication factor (keff) is assumed to be zero in this study.
5.2.3. Calculation case Routine conditions of transport Two calculations are made to evaluate the dose equivalent rate around the TN-MTR cask under routine conditions of transport (RCT).
In routine conditions of transport, the gisete content rests on the bottom of the cavity or on the bottom of the radial wedge, which is itself placed on the bottom of the cavity. It is radially centred apart from the type 4 isotope generator which is slightly off-centre in the cavity. Secure holding of the isotope generator in its internal fitting is guaranteed in normal conditions of transport and therefore also in routine conditions of transport (RCT). On this basis, the parts of the cask where the DERs are at their maximum are either in the bottom axial part or in the uninterrupted section.
To maximise DERs in the bottom axial part and in the uninterrupted section of the cask, the calculations in RCT are performed in the following conservative configurations:
Case 1: source resting on the bottom of the cavity and radially centred. This is a conservative position in terms of DER for the cask bottom end.
Case 2: source at mid-height and stuck the cavity. This is a conservative position in terms of DER for the cask uninterrupted section.
Accident conditions of transport A calculation is made to evaluate the dose equivalent rate around the TN-MTR cask in accident transport conditions (ACT).
According to the analysis of lead slumping given in Chapter 4A and allowing for the degradation to the shielding at the lead shoulder under ACT (slumping of lead following a 9 m drop), the worst position for the DER is when the source is placed in contact with the lid and facing the trunnion.
The radial wedge of the source is considered to be completely failed and the source is free to shift in the radial direction in the cavity of the TN-MTR cask. Along the axial direction, the radioactive source cannot come into direct contact with the lid due to the composition of the axial wedge (presence of a top disc with a diameter equivalent to that of the cavity, and 60 mm thick). The minimum distance between the source and the lid will be more than 60 mm, allowing for the presence of the axial wedge top disc with a minimum thickness of 60 mm.
Therefore the calculation in ACT is made by putting the source at a distance of 60 mm from the lid and sticking it against the cavity and facing the trunnion.
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 8 of 17 NON PROPRIETARY VERSION 5.3. DER calculation points The maximum DER are determined for various locations depending on the calculation cases:
axial top end:
at the centre of the shock absorbing cover, at the lid orifices; radially:
at the bottom end and the top of the trunnions, at the uninterrupted section of the cask; axial bottom end:
in the middle These points are presented in figures 4A-14.3 & 4A-14.4.
5.4. Results 5.4.1. DER in RCT The following table gives maximum DER values around the cask, and 2 m from the package in routine conditions of transport:
Case 1: source resting on the bottom of the cavity and radially centred.
Calculation points DER (mSv/h)
Ref. [4]
contact 2 m Axial bottom end 2.62 x 102 2.53 x 104 11 Case 2: source at mid-height and stuck to the cavity.
Calculation points DER (mSv/h)
Ref. [4]
contact 2 m Radial in uninterrupted section 2.94 x 102 3.69 x 104 9
The DER criterion for contact with the package in routine conditions of transport is therefore met.
5.4.2. DER in ACT The following table gives maximum DER values 1 m from the package, under accident transport conditions:
Calculation points DER (mSv/h) at 1 m Ref. [4]
Axial top end Centre 7.17 x 103 4
Orifice 1.47 x 102 4
Radial Top of trunnions 2
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 9 of 17 NON PROPRIETARY VERSION Calculation points DER (mSv/h) at 1 m Ref. [4]
Bottom of trunnions 1.14 2
Uninterrupted section 4.74 x 101 2
Axial bottom end centre 2.34 x 104 3
The DER criterion under Accident Conditions of Transport is satisfied at all points.
- 6.
Conclusion The TN-MTR cask equipped with the gisete content and its internal fittings meets the criteria shown in paragraph 3 for RCT, NCT and ACT:
in Routine conditions of transport, the dose equivalent rate criterion in contact with the package is met; in Normal conditions of transport, the integrity of the internal fittings which hold the content in position and the limited damage to the package resulting from regulatory tests for normal conditions of transport guarantee compliance with the criterion for an increase in radiation intensity less than 20%;
in Accident conditions of transport, the dose equivalent rate criterion 1 metre from the package is met.
The maximum values of the calculated dose equivalent rates are given in the following table.
DER (mSv.h-1)
Criterion (mSv.h-1)
RCT - Contact 2.94x10-2 2
RCT - 2 metres 3.69x10-4 ACT - 1 metre 2.07 10
- 7.
References
[1] Applicable IAEA regulations: see chapter 00
[2] ORIGEN ARP - Automatic rapid process for spent fuel depletion, decay, and source term analysis OAK RIDGE NATIONAL LABORATORY Report ORNL/TM-2005/39 version6, vol. I, Sect. D1. January 2009
[3] Code TRIPOLI 4.4 - TRIPOLI-4 Version 4 : User manual - Report CEA-R-6170
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 10 of 17 NON PROPRIETARY VERSION
[4] Computer files:
L:\\Archivage\\CDE3086837\\Blindage\\CAL-17-00202702-002-00\\
O-ARP\\
Calculation ref.
sr90_ref-30j.out 1
L:\\Archivage\\CDE3086837\\Blindage\\CAL-17-00202702-002-00\\TRIPOLI\\
ACT\\
Calculation ref.
TN-MTR-GI_CAT_Rad.listing 2
TN-MTR-GI_CAT_AxiB.listing 3
TN-MTR-GI_CAT_AxiH.listing 4
CRT\\
Calculation ref.
TN-MTR-GI_CRT_AxiB_source_fond_centre.listing 11 TN-MTR-GI_CRT_Rad_source_mi-hauteur.listing 9
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 11 of 17 NON PROPRIETARY VERSION List of tables Table Description Pages 4A-14.1 Chemical composition of structural materials 1
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 12 of 17 NON PROPRIETARY VERSION List of figures Figure Description Pages 4A-14.1 TN-MTR cask design - RCT Axial section 1
4A-14.2 TN-MTR cask model - ACT Axial section 1
4A-14.3 Locations of contact measurement points in RCT 1
4A-14.4 Locations of measurement points at 1 m under ACT 1
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 13 of 17 NON PROPRIETARY VERSION Table 4A-14.1 Chemical composition of structural materials Elements Materials Density (g/cm3)
Chemical composition
(% by mass)
TN-MTR Cask Shell steel 7.85 Fe 72 Cr 18 Ni 10 Steel with reduced density 6.91 Fe 72 Cr 18 Ni 10 Lead 11.00 Pb 100 RCT/NCT resin 1.75 16O 48.35 C
22.85 Al 21.48 H
4.63 Cu 1.80 10B 0.16 11B 0.73 Cover Stainless steel 7.85 Fe 72 Cr 18 Ni 10 Wood 0.10 16O 57 C
36 H
7 Air 1.29 x 10-3 N
80.0 16O 20.0
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 14 of 17 NON PROPRIETARY VERSION Figure 4A-14.1 TN-MTR cask design - RCT Axial section Wood in shock absorbing cover Steel of cover Orifice th = 260 mm
ø = 98 mm Lid thsteel = 65 mm thlead = 160 mm thsteel = 35 mm Cavity filled with air
ø = 960 mm h = 1080 mm Bottom of cask thsteel = 30 mm thlead =
thresin =
thsteel = 25 mm Radial shielding thsteel = 20 mm thlead =
thresin =
thsteel = 25 mm Case 1: point source centred in the bottom of the cavity.
Case 2: point source at mid-height and stuck to the cavity
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
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1.0 Page 15 of 17 NON PROPRIETARY VERSION Figure 4A.-14.2 TN-MTR cask model - ACT Axial section Pb slumping in air thaxial = 37 mm Cavity filled with air Pb slumping in air thradial = 4 mm Pb slumping in air thradial = 15 mm Resin in air th =
Point source opposite the trunnion and wedged against the cavity.
Axial lid source distance = 60 mm
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 16 of 17 NON PROPRIETARY VERSION Figure 4A.-14.3 Locations of contact measurement points in RCT Slice 6 Slice 5 Slice 4 Slice 3 Slice 2 Slice 1 Axial bottom end (centre)
Radial uninterrupted section opposite the source for case 2 The calculation points at 2 metres are the same as the points in contact with cask at a distance of 2 metres.
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
DOS-18-011415-045 Version:
1.0 Page 17 of 17 NON PROPRIETARY VERSION Figure 4A.-14.4 Locations of measurement points at 1 m under ACT The uninterrupted section of the cask is divided into different slices. The value given in 5.4.2 corresponds to the maximum reading for the different slices.
Axial top end - centre Axial top end - orifice Top of trunnion Trunnion base 1 m Axial bottom end (centre)