ML21167A151
| ML21167A151 | |
| Person / Time | |
|---|---|
| Site: | 07103088 |
| Issue date: | 03/25/2021 |
| From: | GNS Gesellschaft fur Nuklear-Service mbH |
| To: | Division of Fuel Management |
| Saverot P/NMSS/DFM | |
| Shared Package | |
| ML21167A148 | List: |
| References | |
| GNS B 325/2018 | |
| Download: ML21167A151 (21) | |
Text
Non-Proprietary Version Proprietary information withheld per 10 CFR 2.390
@Gs Containment Analysis for the Type B(U)F Package Transport and Storage Cask CASTOR THTR/AVR Report number: GNS B 325/2018 Rev. 2 Date: 25.03.2021 Number of pages: 21 Name Signature Date Author
- 25.03.2021 Approval Specialist Department 7.03 2w2¥ Release 2603.202a
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev.2 Status of Revision Revision Date Author Reason for change 0 12.11.2018 WTI
- First issue 1 26.06.2020 WTI
- Revision according to LLNL Document Review Report (Docket Number: ) of December 5, 2019 2 25.03.2021 , WTI
- Revision according to LLNL Document Review Report (Docket Number: ) of July 27, 2020
- Section 4: clarification of mobilized activity
- Section 6: including details on leak-tightness of cask's structural components The changes from the previous revision of this report are marked by a vertical black line at the left text margin.
CASTOR is a registered trade mark.
Status of Revision Page 2 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2 Table of Contents Page 1 Introduction and summary 4 2 Containment criteria 4 3 Boundary conditions 5 3.1 Containment system 5 3.2 Package contents 7 3.3 Volumes 7 3.4 Temperatures 8 3.5 Pressures 8 4 Activity and gas mobilization 10 5 Leakage rate acceptance criteria 14 5.1 Calculation model 14 5.2 Allowable leakage rates 15 5.3 Capillary diameter 15 5.4 Reference air leakage rates 16 6 Conclusions 17 List of Tables 19 List of Figures 19 List of References 20 Table of Contents Page 3 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs R ev. 2 1 Introduction and summary The CASTOR THTR/AVR Type B(U)F package (the cask) is designed to accommodate radioactive material from the thorium high temperature reactor THTR-3OO and the high temperature reactor of the Arbeitsgemeinschaft Versuchsreaktor GmbH (AVR).
In this report, a containment analysis is performed for AVR inventories (item 3 of the Authorized Radioactive Contents of the German Approval Certificate 0/4214/B(U)F-96, Rev. 11 [1]). Accor-ding to [1], up to 1900 fuel elements (FE) from the AVR reactor are admissible in each loading.
The demonstration of the compliance of the containment system follows the stipulations in 10 CFR Part 71 [2] under consideration of NUREG/CR-6487 [3] and NUREG-2216 [4]. Allowable activity release rates are determined for normal conditions of transport (NCT) and hypothetical accident conditions (HAG) based on the containment criteria defined in [3] (cp. Chapter 2) along with the corresponding boundary conditions (see Chapter 3) and inventory characteristics (see Chapter 4 ). Analytical calculations by means of the Knudsen equation with a one-capillary model are performed to convert the allowable activity release rates at transport conditions into reference air leakage rates (cp. Chapter 5).
A reference air leakage rate of the containment system of is obtained for the most restricting case, which is NCT.
2 Containment criteria The requirements regarding the containment of the activity for Type B(U) packages are con-sidered as follows (cf. [2] and [3]):
- Normal conditions of transport (NCT):
After testing of robustness under normal conditions of transport, the activity release rate (averaged over one hour) may not exceed the value of R= 10° A/h.
- Hypothetical accident conditions (HAG):
After the sequence of tests required by regulations, the activity release rate (averaged over one week) may not exceed the value of R, = 10 A3/week for Kr-85 or R, = A/week for all other nuclides.
1 Introduction and summary Page 4 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2 The A value of mixtures of radionuclides is calculated as stipulated in [2]:
1 and f(i) = A(i) = A(i) 9, 2>> 6
- A,()
with A: A value of the nuclide mixture; f(i): fraction of the activity of nuclide i to the maximum mobilized activity; A(i): A value of nuclide i (for Kr-85, an A value of 10 A(Kr-85) is used)
A(i): maximum mobilized activity of nuclide i; A: maximum mobilized activity of the nuclide mixture.
3 Boundary conditions In this chapter, the boundary conditions that are used for the containment analysis are compiled.
The general containment requirements for the cask - e. g. appropriate closure of the cask and prevention of unintended opening, no dependence of the containment on filters or mechanical cooling systems, acceptable component temperatures, appropriate size of gasket grooves and material compatibility of cask and inventory - are demonstrated via [5].
3.1 Containment system The containment boundary for the CASTOR THTR/AVR with AVR inventories is constituted alternatively by the following subassemblies (see [6]):
a) Containment with primary lid (1° sealing barrier) cask body (item 2),
primary lid (item 19) and socket head screw (item 32), socket head screw for plumbing seal (item 34) and metal O-ring (item 42 (Al)), as well as protection cap (item 61) in the primary lid, socket head screw (item 39) and metal O-ring (item 73 (Al)).
b) Containment with secondary lid (2" sealing barrier) cask body (item 2),
secondary lid (item 55) and socket head screw (item 62), socket head screw for plumbing seal (item 64) and metal O-ring (item 70 (Al)),
3 Boundary conditions Page 5 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2 protection cap (item 61) in the secondary lid, socket head screw (item 39) and metal O-ring (item 73 (Al)), as well as blind flange (item 89), socket head screw (item 39) and metal O-ring (item 71 (Al)).
During transport, the containment may consist alternatively of the 1°or of the 2" sealing barrier.
The potential leakage paths are shown in Fig. 1(1°sealing barrier) and Fig. 2 (2" sealing barrier).
I Environment I 1
I I Metal O-ring (item 73, Al) Metal O-ring (item 42, Al) in the protection cap (item 61) in the primary lid (item 19) 1 1 I
[ AVR-TL canisters I t
I Fuel and operating elements I Fig. 1: Leakage paths in 1" sealing barrier Environment Metal O-ring (item 73, Al) Metal O-ring (item 71, Al) Metal O-ring (item 70, AI) in the protection cap (item 61) in the blind flange (item 89) in the secondary lid (item 55)
AVR-TL canisters Fuel and operating elements Fig. 2: Leakage paths in 2' sealing barrier The sealing effect is the result of the sealing function of the metal O-rings employed. Each metal O-ring consists of a helical spring made of Nimonic surrounded by an inner jacket of stainless steel and an outer jacket of aluminum (see Fig. 3).
The sealing effect of a metal O-ring is based on the plastic deformation of the outer jacket, which is the result of the pretension force induced by the screwed connection of the lid. The ductility is larger for the outer jacket of the metal O-ring than for the inner jacket, so that the O-ring will adapt to the surface structure of the sealing surface. The function of the inner jacket is to distribute the force due to pressure, which is generated during the compression of the helical spring, uniformly 3 Boundary conditions Page 6 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @GNs Rev. 2 over the outer jacket. For metal O-rings, capillary leakage is the only relevant potential leakage mechanism.
The minimum support width of the metal O-rings is estimated from the torus diameter, resulting in a capillary length of for item 42 and item 70 resp. for item 71 and item 73.
Aluminum Stainless steel Nimonic90 Fig. 3: Structure of a metal O-ring 3.2 Package contents Irradiated and undamaged fuel elements (FE) as well as operating elements (BTE) from the high-temperature reactor of the Arbeitsgemeinschaft Versuchsreaktor GmbH (AVR) are admissible for loadings of the transport and storage cask CASTOR THTR/AVR.
The AVR-FE consist of a large number of particles (approx. 20k to 40k per FE), embedded in a graphite matrix (so called "coated particle concept"). For loadings into the CASTOR THTR/AVR cask, the spherical FE and BTE (diameter: 60 mm) are filled in two AVR dry storage canisters (AVR-TL canisters) placed on top of each other. Each AVR-TL canister may contain up to 960 FE and a maximum of 1900 FE is allowable per cask. Details on the inventory as well as nuclear and thermal data can be found in the corresponding inventory report [7].
3.3 Volumes The minimum free volume in the cask cavity is calculated based on the following volumes:
- Available cask cavity volume:
- displaced volume of the AVR-TL canister: approx.
This results in a minimum free volume in the cask cavity of VG =
3 Boundary conditions Page 7 of 21
Non-Proprietary Version Proprietary information withheld GNS B8 325/2018 per 10 CFR 2.390 @GNs Rev. 2 The volumes are conservatively deduced from [6] and the main canister dimensions in [7]. For a given activity inventory, a minimum Va will lead to maximum activity concentrations (Section 4),
and thus to minimum reference air leakage rates (Section 5.4).
3.4 Temperatures Covering temperatures for AVR inventories are selected from [8] as boundary conditions for the containment analysis. The highest gasket temperature indicated in [8] is taken as the covering value for all gaskets. Temperatures which must be assumed for the gasket, the cavity wall and the inventory for NCT and HAC are shown in Tab. 1.
(cp. Tab. 1).
Temperature, K Component Symbol NCT HAC Gaskets 1 Cavity wall Tw Inventory 1, Cavity gas* 1, Tab.1: Covering temperatures used for containment analysis 3.5 Pressures During dispatching of the cask, the cask cavity of the CASTOR THTR/AVR with AVR-FE is filled with with a total pressure of and a partial pressure of
[9]. The AVR-TL canisters are loaded The pressure pin the cask and in the AVR-TL canisters under normal and accident conditions of transport is obtained according to the ideal gas law from the temperature under transport conditions (cf. Tab. 1) and from the temperature during dispatching of the cask:
p=p*TIT, with po: pressure established in the cavity/canister after loading of the cask; To: average temperature of the cavity/canister gas after loading (= );
T: average temperature of the cavity/canister gas under transport conditions.
3 Boundary conditions Page 8 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2
. This assumption is conservative because the maximum temperature of the inventory is reached at the center of the fuel element canisters while the maximum temperature at the center of the cavity volume is approx. lower [8]. The maximum temperature of the inventory Tis assumed as gas temperature in the canisters.
This leads to the pressures presented in Tab. 2 for the case without canister leakage.
Pressure, kPa Gas NCT HAC Cask cavity AVR-TL canister
- First value: without canister leakage, Second value: with canister leakage Tab. 2: Covering pressures used for containment analysis The Maximum Normal Operating Pressure is the gauge cask cavity pressure in NCT without canister leakage, i. e. .
As can be seen in Tab. 2, the pressure in the AVR-TL canisters is Canister leakage may cause pressure equalization between the cask cavity and the canister atmosphere. The resulting pressure is obtained from the gas volumes in the cask cavity Vc and in the canisters V (cp. Section 3.3) and with the temperatures Ts and T as follows:
The gas volume V in the AVR-TL canisters depends on the number of fuel elements in each of the canisters. Due to the difference in pressures between the cask cavity and atmosphere in the canisters, in the case of the AVR-TL canister, the pressure in the cavity will decrease less if there are more FE in the canisters. When the canisters are full, the gas volume per canister is approximately corresponding to a displacement volume of well as an inherent volume of approx. and an inventory volume (950 FE with 6 cm diameter) of Thus, for two AVR-TL canisters per cask, V=
These volumes VG and h as well as the filling pressures ps and p and the temperatures from Tab. 1 lead to the pressures summarized in Tab. 2. During pressure equalization between cask cavity and canister atmosphere, pressure in the cask cavity will decrease by approx. .
3 Boundary conditions Page 9 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @GNs Rev. 2 4 Activity and gas mobilization AVR-FE consist of a large number of particles embedded in a graphite matrix (cp. Section 3.2).
The coatings of these particles are made of pyrolytic carbon and silicon carbide. They are very tight and mechanically as well as thermally stable. The fuel elements are designed in such a way that under reactor conditions with fuel temperatures of 1150 °C, fission products are retained through the multiple coating of the fuel particles. During transport, fuel element temperatures are below (see Section 3.4 ), so that practically all fission products are present as solids and are bound in the UO or in the UC lattice. With the prevailing conditions, only the release of gaseous nuclides, such as krypton (Kr-85) and tritium (H-3) can occur. In addition, C-14 can be present as gaseous CO arising with the oxygen in the AVR-TL canister atmosphere and is, therefore, included in the following analysis in a conservative way. The reference activities are taken from Tab. 10 in [7].
Kr-85 is generated as a fission product in the coated particles, and is not released when the coating is intact. Only the amount due to heavy metal contamination of the fuel element matrix or coming from failed particles will be released. For the covering AVR-FE Kr-85 are generated during operation per fuel element.
H-3 is mostly generated from impurities of the graphite matrix (e. g. through the (n,a) reaction on Li-6), or through the (n,p) reaction on He-3 in the cooling gas. Thus, tritium will be found mainly outside the coated particles in the matrix material, and must therefore in general be considered as releasable. For the covering AVR-FE of H-3 are generated during operation per fuel element.
C-14 is mainly generated through the (n,p) reaction on nitrogen impurities of the graphite matrix and the cooling gas. C-14 produced from the cooling gas might be dominantly located at the surface of the FE and, when in contact with oxygen, might react to gaseous CO. For the covering AVR-FE of C-14 are generated per fuel element.
Within the scope of the measurement programs [1 O] accompanying the existing canister and cask storage, it was possible to measure the release behavior of gaseous radionuclides with realistic fuel element packagings. The average storage temperature was 30 °C. Release from the FE in closed canisters was measured using special AVR-TL canisters fitted with valves, which offered the advantage of permitting to obtain statistically assured information for a large amount of FE.
In a further series of measurements, the activity release from closed AVR-TL canisters embedded in a CASTOR THTR/AVR prototype due to the plug leakage was checked. For these 4 Activity and gas mobilization Page 10 of21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2 measurements, the prototype cask was fitted with a gas sampling device, so that the nuclide activity accumulated in the empty cask cavity volume could be supervised.
For Kr-85, the development of the releasable inventory, the build-up of activity in the empty cavity volume of the AVR-TL canister and the quantity mobilized from the canister for a leakage rate of 1.10° Pa.m?ls are shown in Fig. 4. The evolution of the mobilized activity was extrapolated from the measurement data under the conservative assumption that only the radioactive decay contributes to a reduction of the releasable inventory. The leakage rate was deduced from the measured activity values, cf. (1 0]. It became apparent from (1 0] that the Kr-85 activity in the canister volume does not increase above 15 MBq, and the mobilization from the canister does not increase above 0.3 MBa for the leakage rate of 1* 10°Pa* m?/s. Neglecting the activity retention by the containment of the AVR-TL canisters, the maximum mobilized activity in the cask atmosphere from two canisters is given by 2 - 15 MBq = 30 MBq.
For H-3, the values are higher by a factor of approx. 2 (Fig. 5). The fact that H-3 is present in the gas volume of the canister in form of HTO, and that a significant part of this HTO is bound to the graphite surface of the FE, due to the desorption/adsorption balance, must be taken into account.
If this balance is disturbed, an increased HTO desorption from the FE surfaces will follow due to exchange with air humidity. Measurements performed on opened AVR canisters containing 50 FE showed that after opening, up to 50 times the activity originally present in the gas volume is mobilized (1 0]. The mobilization rate increased in the first hours and dropped again during the day. An opened AVR-TL canister with 950 FE would thus release maximum 50
- 2
- 15 MBq =
1.5 GBq of tritium as HTO into the cask atmosphere. With two canisters in the cask, the released amount of tritium as HTO into the cask atmosphere is hence 3.0 GBq.
The AVR-TL canisters are loaded under air atmosphere with assumed pressure of pk = (cp. Section 3.5). If all oxygen is consumed to CO, a maximum CO amount of 1.04 mol is obtained based on a free canister volume of and a filling temperature of Measurements (11] showed that a maximum C-14 concentration of 100 Cilg-C can be reached at the FE surface and mobilized with the same concentration into the canister atmosphere. Based on this C-14 concentration, a maximum gaseous C-14 activity of approx. is obtained per canister.
. Hence, an increased maximum value of C-14 is assumed to be released into the cask atmosphere for two canisters.
4 Activity and gas mobilization Page 11 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2 The maximum mobilized activity in the cask cavity is listed in Tab. 3. The listed activity release fraction is the ratio between the mobilized activity and the activity inventory. With the cask cavity volume of this corresponds to an activity concentration in the cask cavity of There is no other relevant mechanism for gas formation, so there is no significant amount of combustible gases in the cask atmosphere.
ACTIVITY (Ci)
KR-85 INVENTORY RELEASABLE INTO AN AVR-TL CANISTER MEASUREMENT VALUE (CANISTERS Willi VALVES)
KR-85 IN THE GAS VOLUME OF AN AVR-TL CANI STER KR-85 RELEASED THROUGH LEAKAGE (1-10'mbar I/s) no MEASUREMENT VALUES (CAST IRON STORAGE CASK) 10 20 30 YEAR S STORAGE TIME Fig. 4: Kr-85 release into and out of an AVR-TL canister (from [101) 4 Activity and gas mobilization Page 12 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @GNs Rev. 2 ACTIVITY (Ci)
H-3 H-3 INVENTORY RELEASABLE INTO AN AVR-TL CANISTER MEASUREMENT VALUE (CANISTERS WITH VALVES)
H-3 IN THE GAS VOLUME OF AN AVR-TL CANISTER m kl.
H-3 RELEASED THROUGH LEAKAGE 1o°1 """"" I MEASUREMENT VALUE (CAST IRON STORAGE CASK) 10 20 0 YEARS STORAGE TIME Fig. 5: H-3 release into and out of an AVR-TL canister (from [10))
Activity Activity Mobilized Activity Nuclide release inventory activity fraction fraction i A'(i), A(i), f(i) A(i), f(i)/A(),
TBq GBq TBq 1/TBq H-3 3.0 4.0E+01 C-14 3.0E+00 Kr-85 0.03 1.0E+02 Sum = 1/A, I A, = I Tab. 3: Mobilized activity of gaseous substances 4 Activity and gas mobilization Page 13 of21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2 5 Leakage rate acceptance criteria The containment criteria defined in Chapter 2 can be expressed in terms of leakage rate accep-tance criteria for the containment system. For this purpose, activity release rates for transport conditions need to be converted into reference leakage rates for standard air conditions.
5.1 Calculation model The volumetric flow rate L from the cask atmosphere is calculated by means of the Knudsen equation. The Knudsen equation describes the combined viscous (first term) and molecular (second term) flow of a gaseous substance through a circular capillary (cp. [3]):
with La(p,) viscous volumetric flow rate, L(pa) molecular volumetric flow rate,
µ dynamic viscosity of the gas, M molar mass of the gas molecules, R universal gas constant (R = 8.314 J* mol'*K'),
T gas temperature within the capillary (gasket temperature),
p upstream pressure, pa downstream pressure, pa average pressure (pa = (po + pa)/2),
a capillary length, D capillary diameter.
The viscous and molecular flow contributions L(pa) and L(p) are defined for an average pres-sure Pa- Since the volume source is located upstream, it is useful to calculate the volumetric flow rate for upstream conditions (cp. [3]):
5 Leakage rate acceptance criteria Page 14 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2 5.2 Allowable leakage rates The allowable leakage rates at transport conditions are obtained from the allowable activity release rates via L(p) = R/Ck and LA(p,) = RX /C, for NCT and HA, respectively, where CN resp. Cx denotes the corresponding activity concentration.
As deduced in Chapter 4, the maximum activity concentration in the cask atmosphere amounts to and the A value of the nuclide mixture equals to . Hence, the following allowable leakage rates are obtained for NCT and HAC, respectively:
- R= results in L = for NCT, R, = results in L = for HAC.
5.3 Capillary diameter The maximum allowable diameter of the equivalent capillary is calculated by solving the Knudsen equation for transport conditions for which the allowable leakage rates are determined (see Tab. 1).
For the calculations, the cask atmosphere is considered as For normal conditions of transport, a reduced ambient pressure of 25 kPa is considered according to [2].
The relevant parameters as well as the capillary diameters which result from solving the Knudsen equation for NCT and HAC are shown in Tab. 4.
Transport condition NCT HAC Gasket temperature T, K Upstream pressure p,,, Pa Downstream pressure p,, Pa 2.5E+04 1.0E+05 Allowable leakage rate L(p,), m'ls Gas Molar mass M, kg/mol Dynamic viscosity (T), Pa*s Capillary length a, m Allowable capillary diameter D, m Tab. 4: Allowable capillary diameters corresponding to allowable leakage rates at transport conditions 5 Leakage rate acceptance criteria Page 15 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2 5.4 Reference air leakage rates The capillary diameters calculated in Section 5.3 for transport conditions are used to determine a reference leakage rate of dry air leaking from p = 1atm to p= 0.01 atm at a temperature of 298 K. The relevant parameters as well as the resulting reference air leakage rates at standard conditions are shown in Tab. 5.
Standard conditions Gasket temperature T, K 298 Upstream pressure p, atm 1.0 Downstream pressure pa, atm 0.01 Gas Air Molar mass M, g/mol 28.9 Dynamic viscosity (T), cP 0.0183 Capillary length a, m Capillary diameter D, m Reference air leakage rate L, ref*cm'ls Tab. 5: Reference air leakage rates The most restrictive reference air leakage rate results from the NCT containment criterion and amounts to The containment system consists of up to four individual components (cask body and gaskets of primary or secondary lid) which may contribute to the total leakage rate of the system (cp. Section 3.1 ).
If one conservatively neglects all retention mechanisms for H-3, C-14 and Kr-85 and assumes that these nuclides are fully mobilized into the cask atmosphere, the activity concentration increases from to and the A value of the gas mixture increases to Repeating the calculation of the reference air leakage rate as described above results in allowable volumetric leakage rates of for NCT resp. for HAC, and a resulting reference air leakage rate of of the containment system for these highly conservative boundary conditions.
5 Leakage rate acceptance criteria Page 16 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2 6 Conclusions The analysis shows that the containment criteria for NCT resp. HAC are fulfilled for the considered AVR inventories of the CASTOR THTRIAVR, provided the standard leakage rate of one barrier of the containment system does not exceed the maximum admissible reference air leakage rate Ln = (corresponding to a standard helium leakage rate of mentioned in Section 5.4. A second barrier is not required, as the fuel is undamaged.
The leak-tightness of the lid sealing system of a loaded CASTOR THTR/AVR has to be proven for each package prior to transport using the specific helium leak-tightness test procedure PV 360/17, Rev. 2 [12). The acceptance criterion therein is predefined to standard helium leakage rate, which is equivalent to a reference air leakage rate of .
The leak-tightness of the cask's structural components of the secondary sealing barrier including the cask body, the secondary lid, the protection cap and the blind flange The target value to demonstrate that leakage through structural components of the CASTOR THTRIAVR would not occur therein is predefined to , which is equivalent to a reference air leakage rate of . The corresponding tests were performed in the period from 2020-09-21 to 2020-11-11 for The measurements yielded an integral standard helium leakage rate of the above mentioned components which fulfills the target. The test report is given in [14).
Provided the leak-tightness of the lid sealing system is fulfilled for a particular cask, compliance with the admissible reference air leakage rate for the entire containment system can be demonstrated. The total standard helium leakage rate of the lid sealing system and the structural components of the cask is limited to less than 6 Conclusions Page 17 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2 which is equivalent to a reference air leakage rate of and is thus below the maximum admissible reference air leakage rate of which was obtained for the most restricting case, i. e. NCT. It should be noted that even the requirement that would result from neglecting all retention mechanisms for H-3, C-14 and Kr-85, i.e.
(see Section 5.4), is fulfilled.
6 Conclusions Page 18 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2 List of Tables Page Tab. 1: Covering temperatures used for containment analysis 8 Tab. 2: Covering pressures used for containment analysis 9 Tab. 3: Mobilized activity of gaseous substances 13 Tab. 4: Allowable capillary diameters corresponding to allowable leakage rates at transport conditions 15 Tab. 5: Reference air leakage rates 16 List of Figures Page Fig. 1: Leakage paths in 1° sealing barrier 6 Fig. 2: Leakage paths in 2" sealing barrier 6 Fig. 3: Structure of a metal O-ring 7 Fig. 4: Kr-85 release into and out of an AVR-TL canister (from [1 OJ) 12 Fig. 5: H-3 release into and out of an AVR-TL canister (from [10]) 13 List of Tables Page 19 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @Gs Rev. 2 List of References
[1] Certificate of Approval D/4214/B(U)F-96, Rev. 11
[2] U.S. Nuclear Regulatory Commission Regulations: Title 10, Code of Federal Regulations, Part 71
[3] Anderson, B. L. et al.
Containment Analysis for Type B Packages Used to Transport Various Contents NUREG/CR-6487, November 1996
[4] Standard Review Plan for Transportation Packages for Spent Fuel and Radioactive Material NUREG-2216, August 2020
[5] GNB B 078/2004, Rev. 0 Typ B(U)F-Versandstück Transport- und Lagerbehlter CASTOR THTR/AVR Sicherheitsnachweis Type B(U)F Package Transport and Storage Cask CASTOR THTRIAVR Safety Verification
[6] GNB B 348/2003, Rev. 0 Typ B(U)F-Versandstück Transport- und Lagerbehlter CASTOR THTR/AVR Behlterbeschreibung Type B(U)F Package Transport and Storage Cask CASTOR THTRIAVR Description of the Packaging
[7] GNB B 329/2003, Rev. 0 Typ B(U)F-Versandstück Transport- und Lagerbehlter CASTOR THTR/AVR lnventarbeschreibung Type B(U)F Package Transport and Storage Cask CASTOR THTRIAVR Description of Inventory
[8] GNB B 334/2003, Rev. 1 Typ B(U)F-Versandstück Transport- und Lagerbehlter CASTOR THTR/AVR Thermische Auslegung Type B(U)F Package Transport and Storage Cask CASTOR THTRIAVR Thermal Design
[9] GNB B 093/97, Rev. 15 Benutzungs- und Wartungsanleitung des Typ B(U)F-Versandstücks Transport- und Lagerbehlter CASTOR" THTRIAVR zur Erfüllung der verkehrsrechtlichen Anforderungen Instructions for Utilization and Maintenance of Type B(U)F Package Transport and Storage Cask CASTOR THTRIAVR for the Fulfillment of Requirements According to Transport Regulations List of References Page 20 of 21
Non-Proprietary Version Proprietary information withheld GNS B 325/2018 per 10 CFR 2.390 @GNs Rev. 2
[10] R. Duwe, A. Christ, U. Brinkmann FuE-Arbeiten zur Zwischenlagerung von HTR-Brennelementen in: Statusseminar Hochtemperaturreaktor-Brennstoffkreislauf Jül-Conf-61, August 1987 R. Duwe, A. Christ, U. Brinkmann R&D Work Concerning the Interim Storage of HTR Fuel Elements in: Status Workshop High Temperature Reactor Fuel Cycle, Jül-Conf-61, August 1987
[11] Kernforschungsanlage Jülich GmbH Technische Notiz IRW-TN-40/88 C 14-lnventar und Freisetzung von Brennelementen in AVR-Trockenlagerkannen 27.05.1988 Nuclear Research Center Jülich GmbH Technical Note IRW-TN-40/88 C 14 inventory and release from fuel elements in A VR dry storage canisters May 27, 1988
[12] PV 360/17, Rev. 2 Dichtheitsprüfung Helium-Dichtheitsprüfverfahren
- CASTOR THTR/AVR -
- Beladung -
Test specification Leak-tightness test Helium leak-tightness test procedure
- CASTOR THTRIAVR - Loading-
[13] PV 360/82, Rev. 3 Test specification Cask structural component - Leak-tightness test Helium leak-tightness test procedure
- CASTOR THTRIAVR-
[14] GNS T 280/2020, Rev. 0 Results of the leak-tightness testing of the CASTOR THTR/AVR cask List of References Page 21 of 21