ML19298A623

Manon Revalidation Letter and SER

ML19298A623
Person / Time
Site:	07103094
Issue date:	10/25/2019
From:	Dan Doyle Storage and Transportation Licensing Branch
To:	Boyle R US Dept of Transportation, Radioactive Materials Branch
BHWhite NMSS/DFM/STL 415.6577
References
EPID L-2018-NEW-0010
Download: ML19298A623 (22)

Text

October 25, 2019 Mr. Richard W. Boyle Radioactive Materials Branch U.S. Department of Transportation 1200 New Jersey Avenue SE Washington, D.C. 20590

SUBJECT:

CERTIFICATE OF APPROVAL NO. F/410/B(U)-96, FOR THE MODEL NO.

MANON PACKAGE - REVALIDATION RECOMMENDATION

Dear Mr. Boyle:

This is in response to your letter dated November 1, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19220A444), as supplemented on May 9, 2019 (ADAMS Accession No. ML19135A160) and October 9, 2019 (ADAMS Accession No. ML19294A084) the U.S. Department of Transportation (DOT) requested that the U.S.

Nuclear Regulatory Commission (NRC) staff perform a review of the French Certificate of Approval F/410/B(U)-96 Revision Ad, for the Model No. MANON transport package and make a recommendation concerning the revalidation of the package for import and export use.

Specifically, you requested that the NRC only review the content in Appendix 3 to the French certificate, specifically the Marguerite 20 radioisotopic thermal generator.

Based upon our review, the statements and representations contained in the application, in the DAHER CSI Package Design Safety Report No. DS-LME50291001, Revision B, as supplemented, and for the reasons stated in the enclosed safety evaluation report, we recommend revalidation of French Certificate of Approval No. F/410/B(U)-96 Revision Ad for the Manon transport package, with the following additional condition:

The Marguerite 20 radioisotopic thermal generator must contain 10 cm of lead surrounding the Sr-90 source on the sides and bottom. Above the source, the Marguerite 20 must have enough copper, steel and air to be equivalent to 18 cm of lead. The Marguerite 20 must further have 1.5 mm of steel surrounding the source on all sides.

R. Boyle If you have any questions regarding this matter, please contact me or Bernard White of my staff at (301) 415-6877.

Sincerely,

/RA/

Daniel I. Doyle, Acting Chief Storage and Transportation Licensing Branch Division of Fuel Management Office of Nuclear Material Safety and Safeguards Docket No. 71-3094 EPID L-2018-NEW-0010

Enclosure:

Safety Evaluation Report

ML19298A623 *via email OFFICE: DSFM DSFM DSFM DSFM DSFM NAME: BWhite SFigueroa* YKim* JBorowsky* JWise*

DATE: 10/15/19 10/18/19 10/16/19 10/16/19 10/16/19 OFFICE: DSFM DSFM DSFM DSFM DSFM ABarto for NAME: VWilson* MRahimi* YDiaz-Sanabria* DDoyle TTate*

DATE: 10/15/19 10/17/19 10/17/19 10/18/19 10/25/19 SAFETY EVALUATION REPORT Docket No. 71-3094 Model No. MANON French Certificate of Approval No. F/410/B(U)-96 Revision Ad

SUMMARY

This is in response to your letter dated November 1, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19220A444), as supplemented on May 9, 2019 (ADAMS Accession No. ML19135A160) and October 9, 2019 , (ADAMS Accession No. ML19294A084) the U.S. Department of Transportation (DOT) requested that the U.S.

Nuclear Regulatory Commission (NRC) staff perform a review of the French Certificate of Approval F/410/B(U)-96 Revision Ad, for the Model No. MANON transport package and make a recommendation concerning the revalidation of the package for import and export use.

Specifically, you requested that the NRC only review the content in Appendix 3 to the French certificate, specifically the Marguerite 20 radioisotopic thermal generator (RTG).

In support of this request the DOT provided the following documents with its letter dated November 1, 2018:

1. French Certificate of Approval F/410/B(U)-96, Revision Ad, dated November 6, 2017.

2. DAHER CSI Package Design Safety Report No. DS-LME50291001, Revision B, as supplemented.

Based upon our review, the statements and representations contained in the application, as supplemented, and for the reasons stated below, we recommend revalidation of French Certificate of Approval No. F/410/B(U)-96 Revision Ad for the Manon transport package.

1.0 GENERAL INFORMATION The packaging for shipment of the Marguerite 20 consists of an external enclosure assembly (EDCE) inside of a casing. The casing is comprised of the upper and lower shell and shock absorber. The cage is not used with the EDCE.

The upper and lower shells are two cylindrical half-shells constructed of austenitic stainless steel, each one made up of a shell with an internal diameter of 1800 mm and a thickness of 20 mm, and each one welded to a disk, 20 mm thick, creating the bases, and a closing flange.

The flanges on the half-shells are constructed of austenitic stainless steel. The upper flange, with a diameter of 2066 mm and a thickness of 32 mm, is fixed to the lower flange (thickness 30 mm) using 30, Class 10.9 screws with a 30 mm diameter by 130 mm length. A 10 mm deep centering hole in the body flange allows the positioning of the two sections.

Enclosure

The shock-absorber on the base of the main body is identical to that placed on the top of the enclosure lid. It provides mechanical protection to the whole assembly. The covers outer shell is cylindrical with a diameter of 2550 mm. The foam is held in place with 3-mm-thick stainless steel plating, which is welded onto the half-shells. The covers are generally crown shaped and recessed to create a zone covering the whole protective shell.

The EDCE has three parts, a body, a lid, and a shimming system. The EDCE body is cylindrical and formed by an upper and a lower shell, lid and body, respectively, each of which is constructed from stainless steel. Each half-shell consists of a cylindrical shell welded to a 20 mm thick plate at the bottom and welded to a flange. The two flanges are fastened together by 18 screws. Two trapezoidal grooves are machined into the upper flange. Each groove holds an ethylene propylene diene monomer (EPDM) O-ring.

Inside each half-shell, both axially and radially, there is a layer of phenolic foam that has a minimum thickness of 100 mm. The foam is protected by stainless steel plating.

The EDCE contains a self-closing vent that is protected by a closure plate made of stainless steel. It is attached to the EDCE by four screws. Two trapezoidal grooves are machined into the closure plate to hold two O-ring seals made of EPDM.

Attached to the EDCE are lifting slings that are attached to three handling studs. The lifting studs are situated on the upper half-shell and are attached to M24 rings, each with a capacity of lifting 3500 kg.

Inside the EDCE is a shimming system to maintain the position of each RTG inside the EDCE.

The RTG is designated as non-removable equipment. DOT requested that NRC review the Marguerite 20 RTG inside the Manon package.

The package has the following approximate dimensions and weights:

Overall package diameter (casing) 2,550 mm Overall package height (casing) 2,574 mm EDCE diameter 1,780 mm EDCE height 1,670 mm 1.2 Contents The package contents consist of a Marguerite 20 RTG, which may contain a maximum of 1700 TBq of Strontium-90 (Sr-90), producing less than or equal to 309 W of decay.

2.0 STRUCTURAL EVALUATION The objective of the structural evaluation is to verify that the structural performance of the package has been evaluated to meet the regulatory requirements of the International Atomic Energy Agency (IAEA) Safety Standards Series, No.SSR-6; Regulations for the Safe Transport of Radioactive Material, 2012 Edition.

2.1 Description of Structures The Manon package is a Type B package designed to transport a Sr-90 RTG, which is designated as non-removable equipment. The package has the following principal structural

components: casing, EDCE, non-removable equipment (i.e., Marguerite 20 RTG) and the internal shimming to secure the non-removable equipment. Detailed descriptions of the structural components are provided in Chapter 03, Description of the Packaging, in the safety analysis report (SAR) and brief descriptions of the safety significant components follow.

The casing is cylindrical in shape and is made of stainless steel 304 and is comprised of a lower half-shell and an upper half-shell with covers for mechanical protection, comprising and a shock-absorbing system, which provides internal mechanical protection for a container. The overall external dimensions of the casing are 2,550 mm in diameter and 2,574 mm in height.

The mass of the casing body (2,210 kg) with casing lid (3,230 kg) is approximately 5,440 kg.

Table 4 in Chapter 03 of the SAR provides mass balance for other structural components. The maximum total allowable mass is 15,600 kg for the package.

The EDCE is used to provide containment for the non-removable equipment and is placed inside the casing. It comprises the following 3 sub-assemblies: (i) a body, (ii) a lid, and (iii) shimming system. The overall dimensions of the EDCE are 1,780 mm in diameter and 1,670 mm in height. The mass of the EDCE body (706 kg) with the lid is approximately 1,450 kg.

The applicant provided the proprietary general assembly drawings and designs of the Manon transportation package in Appendix 1 (RSu LME50291001 Rev. E) and Appendix 2 (RD LME50291001 Rev. D) in Chapter 03 of the SAR.

The staff reviewed the drawings and designs for completeness and accuracy, and finds that the geometry, dimensions, material, components, notes and fabrication details were adequately incorporated.

2.2 Materials Evaluation 2.2.1 Drawings The staff reviewed the drawings and SAR Chapter 04-11, Classification Plan for Safety-Related Components on the Casing, and verified that the applicant provided an adequate description of the component safety functions, materials of construction, dimensions and tolerances, and fabrication (welding) specifications. The staff notes that the austenitic stainless steels used in the casing and EDCE assembly are specified in the drawings as conforming to the Association Française de Normalisation (AFNOR) standard NF EN 10088-2, and there are several potential stainless steel grades that could be used within that standard. However, the specific stainless steel grades and mechanical property requirements are specified in the SAR, and thus the staff finds that the applicant provided sufficient information in the drawings to describe the packaging materials.

2.2.2 Materials Codes and Standards As described in SAR Chapter 3, Description of the Packaging, the Type 304L austenitic stainless steel used in the casing, EDCE assembly, and internal shimming conform to the AFNOR materials standard NF EN 10088-2. The impact limiters are constructed of the proprietary NU280 phenolic foam, and thus the staff evaluated whether the applicant provided sufficient information on the manufacturing and testing of this material to ensure that the foam can meet its intended structural and thermal functions. The staffs review of the foam structural and thermal properties is documented below in SER Sections 2.2.4 and 2.2.5, respectively.

The staff finds the packages materials codes and standards to be acceptable because they adequately provide materials chemistry, mechanical property, and fabrication requirements and their use conforms to the French construction standards, as applicable.

2.2.3 Weld Design and Inspection As described in SAR Chapter 03, Description of the Packaging, welding is performed per the AFNOR welding standard NF P 22-470, Steel Construction - Welded Connections - Details and Design of Welds, using welders that are qualified per AFNOR EN 287-1, Qualification Test of Welders - Fusion welding - Part 1: Steels. The containment boundary welds of the EDCE are full penetration welds.

The package drawings show that all welds are inspected visually and with dye penetrant by a qualified inspector. In addition, the containment boundary welds of the EDCE are also inspected with radiography. The staff reviewed the weld design and finds it to be acceptable because welding and inspection will be performed in accordance to the French construction code.

2.2.4 Mechanical Properties Steels In the package drawings and mechanical calculations, the applicant stated that the mechanical properties of the Type 304L stainless steel used in the casing, EDCE, and shimming were obtained from AFNOR NF EN 10088-2, Stainless Steel - Part 2: Technical Delivery Conditions for Sheets/Plates and Strips for General Purposes, and NF EN 10028-7, Flat Sheet Products for Pressure Vessels - Part 7: Stainless Steels. The staff reviewed the temperature-dependent mechanical properties used in the applicants mechanical calculations and confirmed that the properties are consistent with those the technical literature (e.g., American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section II).

Because the austenitic stainless steels used in the package construction are resistant to brittle fracture at low service temperatures, the staff finds that the applicant has adequately considered fracture behavior in the package design.

Impact Limiter Foam Phenolic foam is used as an impact limiting material in the casing and the EDCE. The foam is also credited in the thermal analyses. The staff verified that the structural analysis and 1/3-scale drop test models employed foams with strengths that result in impact limiter strains and package accelerations that conservatively bound those of the actual package. To ensure the bounding nature of the structural analysis, the SAR defines an allowable range of foam compressive stress. In response to a request for additional information, the applicant provided compressive strength test data on the foam to demonstrate its conformance to the SAR.

The staff reviewed the applicants foam test data and verified that the foam meets the required compressive strength properties. Therefore, the staff finds that the applicant has adequate controls on the foam properties to ensure that the impact limiter can fulfill its structural function.

2.2.5 Thermal Properties of Materials The staff reviewed the thermal calculations in SAR Chapter 04-07, Thermal Analysis, and verified that the density, thermal conductivity and heat capacity of the stainless steel are supported by values available in the technical literature (e.g., American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section II). In response to a request for additional information, the applicant provided additional test data on the effects of temperature on the thermal properties of the foam. The staff verified that the foam thermal conductivity and heat capacity values used in the thermal analysis were consistent with the test data, with the exception of the effects increased density due to foam crushing.

The staff noted that the applicants thermal analysis did not consider the effects of foam crushing on its thermal properties, and this could affect the heat transfer properties of the casing in a fire that occurs after a drop accident. In response to a request for additional information, the applicant provided test data that showed higher foam thermal conductivity at greater foam density (such as might be expected from a crush); however, this higher conductivity was not used in the thermal analysis. Nevertheless, as discussed in Section 3.6 of this SER, the staff determined that sufficient margin exists in the maximum service temperatures of the packaging materials (e.g., seals) to reach reasonable assurance of package performance in a fire accident.

2.2.6 Radiation Shielding Materials In its radiation shielding analysis in SAR Chapter 04-09, the applicant credited only the stainless steel of the EDCE containment boundary. The outer casing and the phenolic foam impact limiting material was not modeled. The staff verified that the applicant appropriately described the density and geometry of the stainless steel in the EDCE, and therefore, finds the material properties used in the shielding analysis to be acceptable.

2.2.7 Corrosion In SAR Chapter 03, Description of the Packaging, the applicant stated that the corrosion resistance of the package is achieved by the use of austenitic stainless steel. In addition, in response to a request for additional information, the applicant stated that the maximum chloride concentration in the FENOSOLTM impact limiter phenolic foam is 20 parts per million, and the applicant referenced a study that demonstrated that the foam does not have a corrosive effect on stainless steel under transportation conditions (Leroy et. al, 2019). The staff also notes that SAR Chapter 05-01, Use and Maintenance of the Packaging, requires the visual inspection of package for evidence of corrosion and cracking before and after each transport operation.

The staff reviewed the materials of the packaging and finds that the applicant adequately considered corrosion resistance because the casing, EDCE, and internal shimming are constructed of stainless steel, which is compatible with the air environments to which the internal and external surfaces of the packaging is exposed. Also, staff reviewed the manufacturer data on the FENOSOLTM foam (Robatel, 2015) and notes that the chloride concentration of the foam is well below levels of 0.5 weight percent that were associated with prior operating experience of transportation packaging corrosion (Kovac, 1994). The staff also notes that the stainless steel shimming is compatible with the steel and lead Marguerite 20 generator. Further, the periodic visual inspections of the package can identify corrosion should it arise.

2.2.8 Seals As described in SAR Chapter 03, Description of the Packaging, the containment boundary seals in the EDCE are constructed of EPDM elastomer. SAR Chapter 03, Section 10.6 and Table 8 provide requirements for the seal hardness, operating temperature range from -55°C

(-67°F) to +170°C (338°F), and thermal expansion.

The staff reviewed the required seal characteristics and technical resources on EPDM seals and verified that EPDM is capable of meeting the seal requirements. EPDM typically has heat resistance up to 150°C (302°F) for normal service and 204°C (399°F) for short term exposures (Parker, 2007). The staff notes that the applicants thermal analysis determined that the seals reach a maximum temperature of 141°C (286°F) in a fire. EPDM maintains cold flexibility down to approximately -57°C (-71°F). The staff also verified that EPDM is capable of meeting the hardness and thermal expansion requirements of the applicants design.

In addition, SAR Chapter 05-01, Use and Maintenance of the Packaging, requires that the condition of the seals and mating surfaces be examined before and after each transport operation and that seals be replaced every 3 years.

Based on the staffs evaluation of the capability of EPDM to meet the seal requirements in the applicants safety analysis, and the fact that the seals will be periodically examined and replaced, the staff finds the seal material to be acceptable.

References Parker. Parker O-Ring Handbook, Parker Hannifin Corporation, Cleveland, Ohio, 2007.

Leroy, C., Lhostis, V., Segarra, C., and P. Laghoutaris, Study of the Occurrence of Hidden Corrosion in Packaging Steels, Exposed to Potentially Corrosive Materials such as Resin, Compound, or Foam, in Conservative Temperature/Humidity Conditions, Paper 1132, Proceedings of the 19th International Symposium on the Packaging and Transportation of Radioactive Materials, PATRAM 2019, New Orleans, LA, August 4-9, 2019.

Kovac, F.M., 21PF Overpacks: Phenolic-Foam Induced Corrosion, Institute of Nuclear Materials Management Annual Meeting, Naples, Florida, July 17-20, 1994.

Robatel Industries, FENOSOLTM technical data sheet, Rev. 0, 2015.

2.3 Structural Analyses 2.3.1 Strength Analysis of the Containment Enclosures The applicant performed a structural analysis to demonstrate the strength of the enclosures in the package comprising the casing, and the EDCE when they are subjected to regulatory pressures under normal conditions of transport and accident conditions of transport.

The applicant adopted the three design criteria per IAEA regulation requirements: (i) a maximum normal operating pressure lower than the pressure of 700 kPa, (ii) a decrease in ambient pressure to 60 kPa, during which the enclosure must retain the radioactive content, and (iii) an external overpressure of 150 kPa, following an immersion test. The applicant used ANSYS finite element (FE) computer program and built structural models (EDCE with enclosures) to calculate the induced stresses of the structure subjected to the required regulatory pressures under normal conditions of transport and accident conditions of transport.

Tables 1 and 2 in Section 5.5.1, Decrease in Ambient Pressure to 60 kPa, in Chapter 04-01 of the SAR included results of the structural analysis for the case of lowering the ambient pressure to 60 kPa under normal conditions of transport. The results showed that the induced stresses on the all enclosures were below permissible stress limits. The results also indicated that the fastening screws of the lids and closure plates on the EDCE remained securely fastened and therefore containment of the EDCE was maintained. The staff found that the EDCE has sufficient structural integrity to withstand a lowering ambient pressure without losing containment, down to 60 kPa, and that the IAEA regulatory requirements were met.

Tables 3, 4 and 5 in Section 5.5.2, External overpressure of 150 kPa, in Chapter 04-01 of the SAR provide results of the structural analysis for the case of increasing external pressure to 150 kPa under accident conditions of transport. The results show that the induced stresses are below permissible stress limits. The results also indicate that the fastening screws of the lids and closure plates on the EDCE remained securely fastened and therefore containment of the EDCE was maintained. The staff found that the EDCE has sufficient structural integrity to withstand a lowering ambient pressure without losing containment, down to 60 kPa, and that the IAEA regulatory requirements were met.

2.3.2 Strength Analysis of the Tie-Downs, Handling Devices, Lifting Components and Stacking The applicant performed structural analysis to demonstrate the strength of the tie-downs, handling devices, lifting components and stacking. The applicant utilized the ANSYS FE computer program. Descriptions of the FE structural modeling with the analytical assumptions and design criteria are provided in Chapter 04-02 of the SAR.

In Section 5, Strength of the Tie-Down and Handling Devices, in Chapter 04-02 of the SAR, Tables 1, 3 and 4 provide the results of the structural analysis for the calculated stress at the lifting points of the casing and EDCE, the calculated stresses for the tie-down lugs and casing shell and the calculated stresses on weld beads, respectively. The results show that all calculated stresses are less than the permissible stress limits and meet the IAEA regulatory requirements.

In Section 6, Strength of the Lifting Components and Other Elements of the Packaging, in Chapter 04-02 of the SAR, Table 6 provides the results of the structural analysis for the removable components. The results show that all calculated stresses are less than the permissible stress limits and meet the IAEA regulatory requirements.

In Section 7, Stacking, in Chapter 04-02 of the SAR, the applicant provides a buckling analysis and its result for the package. The IAEA SSR-6, 2012 Edition requires that the Manon package be subjected to the greater of 5 times the mass of the package or 13 kPa times the vertically projected area of the package. Using the greater of these two, the applicant calculated an allowable buckling load of 2.8x108 N, which is more than 300 times the load induced by the stacking of five packages (735,750 N). The applicant concluded that the Manon transportation package meets the IAEA regulatory requirements for the stacking.

The staff reviewed the analysis results submitted by the applicant and agrees with its conclusions that the package components (i.e., tie-downs, handling devices, lifting components and other elements) have adequate strength to meet the regulatory requirement of IAEA SSR-6, 2012 Edition.

2.4 Normal and Accident Conditions of Transport The applicant performed a series of drop tests using 1/3-scale model to demonstrate structural integrity and performance of the package under normal conditions of transport and accident conditions of transport. The model tests were planned and carried out in accordance with the requirements of IAEA SSR-6, 2012 Edition.

Three drop tests sequences were performed to evaluate the casing, EDCE and Marguerite 20 for both the normal conditions of transport drop test and accident conditions of transport drop tests. The minim free fall drop test heights onto a flat target were 0.75 m and 9.76 m for normal conditions of transport and accident conditions of transport, respectively, and the height for the drop onto a puncture bar for hypothetical accident conditions of transport was 1.47 m. The drop test orientations were chosen to cause maximum damage to the package. Chapters 04-04 and 04-05 of the SAR provide detailed information for the drop test program.

The applicant provided detailed test results in Chapter 04-06 of the SAR. In summary, the main test results are following: (i) the cumulative damage from the drop tests show that those elements related to the safety functions performed well with respect to the mechanical behavior (i.e., blocking systems, lids, vent orifices) as well as preventing the dispersal of radioactive materials beyond the containment system, (ii) the damage to the specimen was limited to varying levels of strain in the casing, (iii) the post-test leakage rates were the same as the pre-test leakage rates, and (vi) there was no rupture of the closure system. Based on the results of the tests, the applicant concluded that the sources and non-removable equipment in the Manon package will not undergo any structural functional failures under normal conditions of transport and accident conditions of transport.

2.5 Evaluation Findings

Based on the review of the statements and representations contained in the application, the staff concludes that the structural designs for the Manon transportation package has been adequately described and evaluated and that the package has adequate structural integrity to meet the structural requirements of the IAEA SSR-6, 2012 Edition.

3.0 THERMAL EVALUATION 3.1 General Considerations Manon is a Type B package designed to transport a Sr-90 RTG, which is designated in the application as non-removable equipment. According to Chapter 03 (page 23/46), the package is Type B(U) and designed for non-exclusive use.

3.2 Thermal Design Features According to Chapter 03, the RTG is placed within an EDCE, which is then placed within the cavity of the Manon casing. Both the Manon casing and the EDCE consist of a stainless steel outer skin and inner skin. The casing cylindrical enclosure and the EDCE enclosure consist of two stainless steel (austenitic, per page 4/5 of Chapter 04:08) half-shells; phenolic foam (DL NU280h) is placed at each half shell. There is no mechanical cooling system.

According to Chapter 03 (page 26/46) and Chapter 04-04 (page 18/39), the Manon casing and the phenolic foam associated with the Manon casing and EDCE provides thermal protection at the high temperatures of the hypothetical fire accident and is effective at -40 °C. Note on Thermal Calculations (NC LME 50291001-08 rev. C) indicated that properties of the foam were referenced in document DSTM9665 Rev. A NU280H (page 8/21). Chapter 04:08 indicated that the FENOSOL phenolic thermosetting foam is placed axially and radially around the casing and EDCE and is held in place by 3-mm-thick stainless steel plates; additional foam details were provided in the October9, 2019 submittal. Chapter 03 (page 19/46) indicated that phenolic foam is placed on the outside of the Manon casing, which is comprised of a lower half-shell, upper half-shell, and a shock-absorbing system made from phenolic foam. The half-shells are fabricated from austenitic stainless steel and are 20 mm thick. The bases are made from 20-mm-thick stainless steel.

Chapter 03 page 29/46 indicated that the welds associated with the casing and the EDCE are per AFNOR NFP 22 470, Steel Construction - Welded Connections - Details and Design of Welds. The welds of the EDCE containment are full penetration and the filler material is based on the mechanical properties of the metals used in construction. All welds are inspected using a dye penetrant method and a tensile test is carried out on representative samples of each welding procedure used.

According to Chapter 03 Section 6.5.2.6 and Section 7.2.1.4, both the Manon casing and the EDCE have thermal fuses located in their outer periphery; the fuses are holes that are filled with polyurethane mastic and pellets of polyethylene with a melting point lower than 180 °C; additional details were provided in the October 9, 2019 submittal. Section 7.2.1.4 stated that the fuses allow water vapor from the phenolic foam to dissipate from the foam during a fire scenario. Section 7.2.1.4 indicated that the thermal fuses and mastic have a compatible temperature range between -40 °C and 70 °C. According to Chapter 04-11, the thermal fuse is an important-to-safety component (page 15/19) and must meet a certificate of conformity. The Packaging Maintenance Manual (page 8/27 and 9/27) states that the packages systematic maintenance test includes checking the condition of the thermal fuses and ensuring the absence of seepage and streaking.

3.3 Decay Heat The Radioactive Release Study (U-8021-NT-02, rev 1) indicated that the bounding Sr-90 source in the radioisotope generator (i.e., non-removable equipment) has an activity of 1700 TBq (page 4/18). The thermal analyses presented in Note on Thermal Calculations (Document No.

NC LME 50291001 08 rev. C) were based on an internal power of 309 W, with reference to the Marguerite 20 RTG (Chapter 2, page 9/10).

3.4 Summary of Temperatures Chapter 4 provided a summary of temperatures for normal conditions of transport and accident transport conditions. A listing of these temperatures is provided below in SER Section 3.5 and Section 3.6; the listed temperatures were less than their allowable values.

3.5 Thermal Evaluation for Normal Conditions of Transport Chapter 4 (page 6/12) indicated that the ANSYS 11 FE analysis software was used for the thermal analysis. According to page 11 of 21 of the Document No. NC LME 50291001-08, Rev. C Note on Thermal Calculations, analyses were based on the package being in a horizontal orientation and a vertical orientation; maximum temperatures were reported for the horizontal orientation. The three-dimensional EDCE model included the shell, end plates, and blocks of NU280 phenolic foam. According to Chapter 4 (page 9/21) and the October 9, 2019 submittal, the 309 W decay heat was applied homogeneously to the wall of a cavity simulating the space occupied by the RTG.

In terms of modeling inputs and boundary conditions, Section 6.4 (page 8/21 of Note on Thermal Calculations) provided the density, thermal conductivity, and heat capacity of the 304L stainless steel and foam that comprise the EDCE. Section 6.5 indicated that the models ambient air temperature boundary condition was 38 °C. Section 6.6.2 provided the heat transfer coefficient correlations for the horizontal and vertical surfaces, although, according to the French certificate (F/410/B(U)-96 Revision Ad, Appendix 3, page 2/13), the package is designed to be handled, loaded, and transported in a vertical position. Emissivity of the steel structure was taken as 0.2. Solar radiation was 800 W/m2 on horizontal surfaces and 200 W/m2 for vertical surfaces; the solar absorptivity coefficient was 0.4. It is noted that according to Chapter 05-01 (page 5/37), the package may not be transported in a contained manner.

Results described in Chapter 04-07 (page 6/12) show that the package surface temperature is 48 °C, which is less than the 50 °C regulatory limit for non-exclusive use transportation.

Likewise, the mean temperature of the foam located in the protective covers and the gaskets were below their maximum service temperatures, as reported in Chapter 04-04 and Chapter 04-07.

Chapter 04-08 stated that the EPDM gaskets and the phenolic foam retain their effectiveness at

-40 °C. Page 4/5 stated that the EPDM gaskets are guaranteed to -55 °C, per the Stacem Technical Data Sheet F-DEV-04-02.

The applicant stated in Chapter 04-07 (page 7/12) that the average air temperature within the cavity was 113 °C under normal transport conditions, which would correspond to an internal pressure of 1.33 bar (133 kPa). Likewise, page 7/18 of the Radioactive Release Study (U 8021-NT-02, rev 1) listed an absolute pressure in the EDCE cavity as 1.334E5 Pa and Chapter 04-01 (page 5/9) indicated that maximum normal operating pressure was 32 kPa

gauge. The Note on Thermal Calculations (page 14/21) stated that the EDCE pressure during the thermal accident condition was 1.44 bar (144 kPa). Section 5.5 of Chapter 04-01 indicated safety coefficients between 1.3 and 3 regarding the structural integrity of the EDCE for decreases in ambient pressure to 60 kPa and for external overpressures of 150 kPa; therefore, the results show safety coefficients greater than one for EDCE pressures during operations. It is noted that Chapter 04-01 (page 5/9) indicated that there is no material within the contents that would result in gaseous discharge (e.g., radiolysis).

3.6 Thermal Evaluation for Accident Conditions of Transport According to Notes on Thermal Calculations Section 7.3, the transient thermal analysis used the package temperatures at normal conditions as initial conditions. Section 6.6.3.2 indicated the emissivity of the external package surface was 0.8 during and after the fire. The flame emissivity was taken as 1. Section 6.6.2.2 stated that the convective heat transfer coefficient between the package and the 800 °C fire was 10 W/m2-K; the casing surface temperature was equal to 800 °C. After the 30 minute fire, the convection heat transfer coefficient correlations were those used during normal conditions; likewise, solar radiation was applied during the cool-down portion of the transient.

Results from Notes on Thermal Calculations Section 7.3.1 (page 13/21) indicated that the outer package (i.e., casing) had a maximum temperature of 800 °C. In addition, gaskets reached a maximum temperature of 141 °C after 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 45 minutes. As noted earlier, the gaskets were reported to have a 170 °C allowable temperature. Temperature transient profiles (up to 100,000 seconds) of the EDCE cavity and gasket were provided in Figure 10 (page 21/21). It is noted that, according to Notes on Thermal Calculations Section 7.3, the calculations took into consideration the damage to the package after the lateral drop by modeling a reduced insulation thickness. The applicant noted in the October 9, 2019 submittal that a higher density foam of the casing would have a 0.122 W/m2-K thermal conductivity.

Although this value was not modeled, its thermal effects would not exceed the nearly 30°C margin of the gasket temperature. In addition, according to the October 9, 2019 submittal, the lead surrounding the Sr-90 source was at 239 °C during the thermal accident condition; this temperature is less than the leads 327.5 °C allowable temperature.

The air in the enclosure assembly reached a temperature of 144 °C after 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 20 minutes.

The applicant used the Ideal Gas Law to calculate a 1.44 bar (144 kPa) absolute internal pressure within the EDCE during accident conditions. As noted above, Section 5.5 of Chapter 04-01 indicated safety coefficients between 1.3 and 3 regarding the structural integrity of the EDCE for decreases in ambient pressure to 60 kPa for external overpressures of 150 kPa.

3.7 Conclusion Based on a review of the relevant portions of the French certificate and the representations in the application, the staff has reasonable assurance that the Manon package with non-removable equipment (Marguerite 20) with a maximum decay heat of 309 W meets the thermal requirements of IAEA SSR-6 2012 edition.

4.0 CONTAINMENT EVALUATION 4.1 General Considerations Manon is a Type B package designed to transport a Sr-90 RTG, which is designated in the application as non-removable equipment. The package consists of the Manon casing, the EDCE, non-removable equipment/radioisotope generator (Marguerite 20) and the internal shimming to secure the non-removable equipment (details on page 16/19 of Chapter 04-11 and French Certificate (F/410/B(U)-96 Revision Ad, Appendix 3, page 3/13, Chapter 03 page 41/47).

According to Chapter 03 (page 23/46), the package is Type B(U) and designed for non-exclusive use.

4.2 Description of Containment System The Radioactive Release Study (U-8021-NT-02, rev 1; page 4/18) and Chapter 04-10 (page 7/8) indicated that the EDCE is the containment boundary, which, according to Chapter 03 (page 16/4 and 23/46), consists of lid and lid gaskets (i.e., O-rings), closure plate and closure plate gaskets, 20-mm-thick stainless steel upper and lower plates, and two stainless steel cylindrical half-shells that are 8 mm thick, with each half-shell having a stainless steel flange.

The upper flange is 45 mm thick and has two concentric trapezoidal grooves that hold EPDM O-rings; the two grooves enclose a volume used for containment testing. Chapter 03 page 16/46 indicated that a 48 mm thick stainless steel closure plate protects the EDCEs self-sealing coupling vent (i.e., STAUBLI quick connection) and includes two concentric trapezoidal grooves. According to the French Approval Certificate F/410/B(U)-96 Revision Ad (page 2/13 of Appendix 3), the four grooves hold EPDM O-rings of grade 48DRL13 by STACEM or EP8517 by Joint Français; the item number for the EPDM O-rings on the safety directory parts list is included in Table 1 of Chapter 05:01. Table 5 of the Packaging Maintenance Manual and Chapter 03 (page 44/46) provide the containment EPDM O-ring and test EPDM O-ring dimensions and note that the EPDM has an 80 Shore A hardness value. The October 9, 2019 submittal stated that all O-ring gaskets have a minimum crushing ratio of 15%. Figure 3 and Figure 4 of Chapter 05:01 provide sketches of the EDCE lid sealing and the EDCE vent closure plate sealing; similar information was provided in Figure 1 and Figure 2 of the Packaging Maintenance Manual. The Radioactive Release Study (page 6/18) stated the EDCE has a venting self-plugging connector that is protected by a closure plate; there is no filter, no mechanical cooling system, and no feature that allows continuous venting during transport.

According to Chapter 03 (page 43/46) and Chapter 05-01 (page 22/37), the closure of the Manon casing includes M30 screws (30 quantity) with an 850 Nm tightening torque. Likewise, the closure arrangement of the EDCE is secured by M24 EDCE screws (18 quantity) with a 760 Nm tightening torque and M10 EDCE closure plate screws (4 quantity) with a 35 Nm tightening torque. Finally, Chapter 05:01 (page 5/37) indicated that safety seals are included to prevent access to the container.

Chapter 03 page 29/46 indicated that the welds associated with the casing and the EDCE are per AFNOR NFP 22 470, Steel Construction - Welded Connections - Details and Design of Welds. The welds of the EDCE containment are full penetration and the filler material is based on the mechanical properties of the metals used in construction. All welds are inspected using a dye penetrant method and a tensile test is carried out on representative samples of each welding procedure used.

Description of Content The content consists of a Sr-90 RTG designated as non-removable equipment; there is no plutonium in the content. According to the Packaging Maintenance Manual, page 4/27, the non-removable equipment includes a Marguerite 20 radioisotope generator. Chapter 02 page 9/10 (and the Radioactive Release Study, page 4/18) indicated that the Marguerite 20 is the bounding content, with an activity of 1700 TBq and a decay heat of 309 W. Chapter 02 (page 8/10) indicated that the Sr-90 is in the form of sintered pellets.

Description of Containment System Performance The Radioactive Release Study provided the calculations to determine the permissible leakage rate and the permissible standard leakage rate of the EDCE containment boundary.

Page 6/18 stated that the calculations were based using the procedure provided in ISO 12807.

Although it was noted in Chapter 03 (pages 15/46 and 24/46) that the RTG non-removable equipment provides radiological protection such that the RTG provides confinement of the sintered Sr-90 pellets, the analysis assumed an aerosol concentration of 9 g/m3 (page 6/18 of Radioactive Release Study) in the EDCE throughout the accident scenario; no credit was taken for the radioisotope generator structure. The analysis in Chapter 04-10 indicated that releases would not exceed the regulatory limit of 10E-6 A2/hr (normal conditions of transport) and A2/week (accident conditions of transport) with testing of the EDCE (welds, lid gaskets, and cover plate gaskets) to a standard permissible leakage flow rate acceptance criterion of 6.2E-4 Pa m3/sec SLR.

The condition of the containment boundary after normal conditions and accident condition tests was discussed in various chapters. The Note on Thermal Calculations (NC LME 50291001-08 rev. C) indicated that the maximum temperatures of the gaskets under normal conditions and accident conditions of transport were below their respective limit values. Chapter 04:03 indicated that structural performance of the package containing the Marguerite 20 RTG in the EDCE was modeled using the LS-DYNA code and pages 9/14 and 10/14 state that the strains of the EDCE body and lid related to normal conditions of transport and accident conditions of transport drop tests and puncture tests were below permissible limits. In particular, Figure 6 (page 9/14) indicated there was no plastic strain at the EDCE sealing surface. According to Chapter 04-03, the radioisotope generator non-removable equipment is secured in the EDCE such that it will not impact the EDCE closure during the 30 ft drop test and thus, not cause a larger than analyzed leakage pathway. In addition, Section 5.5 of Chapter 04-01 indicated safety coefficients between 1.3 and 3 regarding the structural integrity of the EDCE for decreases in ambient pressure to 60 kPa and for external overpressures of 150 kPa. Further discussion of the structural calculations is provided in the structural evaluation of the SER.

Finally, it was noted in the October 9, 2019 submittal that the foam associated with the casing and EDCE is non-flammable, such that combustible gas generation would not be an issue.

The Packaging Maintenance Manual (page 23/27) stated that an air leakage rate test is used to confirm sealing of the lid/flange containment gasket has a leakage flow test acceptance criterion of 1.1E-5 Pa m3/sec SLR. Likewise, an air leakage rate test used to confirm sealing of the closure plate containment gasket has a leakage flow test acceptance criterion of 1.1E-5 Pa m3/sec SLR. The air leakage flow rate test procedure was provided on page 24/27.

Page 15/27 also stated that External Enclosure Assembly welds undergo a commissioning factory fabrication helium leakage rate acceptance test that has an acceptance criterion less than 1.1E-8 Pa m3/sec SLR. The procedure for conducting the helium leakage rate test was provided on page 23/27. It is noted that these details support the discussion in Chapter 03

(page 31/46) that stated EDCE enclosure welds are helium leak tested using the integral vacuum method and the EDCE gaskets on the containment flanges and gaskets associated with the vent orifice closure plate are leak tested using a pressure rise method.

The Packaging Maintenance Manual described Systematic maintenance, Minor maintenance, and Major maintenance activities associated with the Manon casing and the EDCE. The Systematic testing activities that are performed before each use include replacing each EDCE gasket and visually inspecting the gasket contact surface. Although not listed in the systematic maintenance table found in the Packaging Maintenance Manual, it is noted that a pre-shipment leakage rate test is performed after loading of the radioisotope generator in the EDCE.

Specifically, pages 12/37 and 13/37 of Chapter 05:01 indicate that, as part of loading, the lid/flange gaskets and closure plate/gaskets undergo an air leakage rate pressure rise test with acceptance criteria of 1E-5 Pa m3/sec SLR, as described in Appendix 1 (pages 27/37 and 28/37). It is noted that the information in Appendix 1 provides the same information as found on pages 23/27 and 24/27 of the Packaging Maintenance Manual. The Minor maintenance activities that are performed every 3 years or 30 cycles (i.e., loading) include the above mentioned systematic testing activities and penetrant examination on the Manon casing and EDCE welds. In addition, the containment lid/flange gasket and cover plate gasket undergo a leakage rate test with an acceptance criterion of 1.1E-5 Pa m3/sec SLR (acceptance criterion also reported in the October 9, 2019 submittal). The Major maintenance activities that are performed every 6 years or 60 cycles (i.e., loading) include the above-mentioned systematic testing and minor maintenance activities. In addition, page 8/27 indicated that the Manon casing and EDCE welds undergo a penetrant examination and a helium leakage rate test; the October 9, 2019 submittal indicated that the helium leakage rate test has a total (i.e., summed) acceptance criterion of 1.1E-8 Pa m3/sec SLR. The October 9, 2019 submittal also clarified that the weld helium leakage rate tests with the 1.1E-8 Pa m3/sec SLR acceptance criterion would occur whenever there was a weld repair, irrespective of a 3 year or 6 year timeframe. Likewise, page 9/27 indicated that the containment lid gasket and cover plate gasket undergo an air leakage rate test with a summed acceptance criterion of 1E-5 Pa m3/sec SLR. Leakage rate tests are to be performed by qualified personnel in accordance with the listed COFREND quality assurance system. As part of the Major maintenance activities, the EDCE gasket contact surfaces are inspected with a roughness meter; the October 9, 2019 submittal included acceptance criteria and indicated that the contact surface of the flange and plate would have an RA surface roughness equal to 0.4 and the grooves would have a RA surface roughness of 0.8.

4.3 Conclusion Based on a review of the relevant portions of the French certificate and the representations in the application, the staff has reasonable assurance that the Manon package with non-removable equipment content with a maximum decay heat of 309 W (e.g., Marguerite 20) meets the containment requirements of IAEA SSR-6 2012 edition.

5.0 SHIELDING EVALUATION The staff reviewed the application to ensure that the shielding is adequate to meet the radiation level requirements within the IAEA Safety Standards for protecting people and the environment, Regulations for the Safe Transport of Radioactive Material, 2012 Edition, Safety Specific Requirements No. SSR-6 (SSR-6) for this type of package. Specifically, Paragraph 526 of the SSR-6 requires that the transport index (TI) shall not exceed 10. Per paragraph 523 of the SSR-6, this means that the radiation level cannot exceed 0.1 mSv/hr (10 mrem/hr) at 1 meter from the package. Paragraph 527 of the SSR-6, for non-exclusive use packages, requires that

the maximum radiation level at the surface of the package does not exceed 2 mSv/hr (200 mrem/hr). For Type B(U) packages, Paragraph 652 requires that the package meet the requirement in Paragraph 648 of SSR-6. Paragraph 648(b) states that under normal conditions of transport that the package not experience more than a 20% increase in the maximum radiation level. Paragraph 659(b)(1) of the SSR-6 requires that the package does not exceed 10 mSv/hr (1000 mrem/hr) at 1 meter under accident conditions.

DOT limited its requested revalidation to the content described in Appendix 3, which consists of an EDCE loaded with the Marguerite 20 generator containing Sr-90 sources.

The Manon package consists of the Manon casing. The EDCE is placed inside of the casing, it consists of a special purpose shimming system which is used to hold the Marguerite 20. The Marguerite 20 is a Sr generator. Along with 6 other generators, not being requested for revalidation, these are collectively referred to within the application as non-removable equipment. The application states that these consist of Sr-90 sources within a lead biological protection cask.

The staff reviewed the drawings of the Marguerite 20, Drawing Nos. 1ME50291522 and 1ME50291522. The mass of the Marguerite 20 is stated in Table 5-1 of the application (Document No. DS LME 50291001-02 Rev. D) and is limited to 4,000 kg. The source is specified in Table 5-2 of the application (Document No. DS LME 50291001-02 Rev. D). This table states that the source was 4,255 TBq at loading on February 6, 1969. As of January 9, 2006, Table 5-2 of the application states that the activity was 1,699.42 TBq.

5.1 Source Modeling Sr-90 beta decays to Y-90 which beta decays into Zr-90, a stable nuclide. Because the half-life of Sr-90 is much longer than that of Y-90, and based on the amount of time since loading, the two would be in secular equilibrium. Although the beta emissions from the Sr-90 and Y-90 would be easily stopped by the package components, the beta particles interacting with the lead (a high Z material) would create bremsstrahlung photons that need to be considered when evaluating radiation levels. The maximum beta emitted from Sr-90 is 0.546 MeV with an average energy of 0.196 MeV and from Y-90 the maximum beta emitted is 2.284 MeV with an average energy of 0.935 MeV. The applicant uses the MCNP code in the coupled electron photon mode to calculate the radiation level. In the electron mode, MCNP simulates bremsstrahlung production. The staff found this code capable and acceptable for performing this simulation.

The applicant states that it neglected the bremsstrahlung dose rate for Sr-90 as its beta energy is so much lower than that of Y-90. Although the staff found it non-conservative to neglect the Sr-90 contribution, it finds that it would be small and that there is significant margin to the SSR-6 radiation level limit for this application and found it acceptable to neglect Sr-90. The applicant provides the beta energy spectrum for Y-90 in Figure 1 of Page 2 of Enclosure 1 to Oranos letter submitted May 9, 2019 by DOT. The staff found the shape and magnitude of the beta spectrum consistent with literature (Cember, Introduction to Health Physics, 1996 (ISBN 0-07-105461-8)).

The applicant modeled the source as a point source within the Marguerite 20. This is a conservative source geometry and the staff found it acceptable.

5.2 Evaluation Method The applicant calculated the external radiation level of the package using the MCNP 6.1 code.

This code includes electron photon transport capability and is widely used and therefore the staff found it capable of performing this simulation.

The applicant validated its method by comparing it to a study in Reference 3 of Enclosure 1 of Oranos letter submitted May 9, 2019 by DOT that calculated the lead shielding requirement for Sr-90/Y-90 bremsstrahlung sources. This reference gives a numerical equation confirmed by experiment for calculating the dose for lead shield up to 10 cm. The difference between the referenced papers method and that of the applicants is that the applicants was 19% lower. This is expected given the difference in flux to dose rate conversion factors used between the two methods.

The staff further found that this justifies that the applicants method for evaluating the dose rate from the bremsstrahlung source from beta radiation from Y-90 through the lead target is acceptable.

5.3 Package Modeling On Page 3 of Enclosure 1 to Oranos letter submitted May 9, 2019 by DOT, the applicant states that it modeled the source inside an 18 cm lead cylinder surrounded by a 1.5 mm thick stainless steel cask with a radius of 73 cm. The cask is modeled as steel with 8 mm thickness on the sides and 20 mm thickness on the top and bottom. The applicant calculates the radiation level of the Manon package with the Marguerite 20 source located at the center and also against the side of the cask wall. The Marguerite 20 source against the side of the cask wall gives the most conservative results as this minimizes the distance between the source and the detector.

The staff was unable to verify the dimensions of the lead and steel within the Marguerite 20 in the package drawings and is therefore including a condition for revalidation that the Marguerite 20 include 18 cm of lead on the sides and bottom surrounding the source. The top of the Marguerite 20 does not have lead shielding and instead consists of copper, steel and air as discussed in the October 9, 2019 supplement, and therefore for the top of the Marguerite 20 the staff is requiring an equivalence of 18 cm of lead in copper, steel and air. Typically, the staff requires additional qualifications on determining equivalence, but in this case the staff found that the Marguerite 20 shielding needs to be credited to shield the bremsstrahlung photons generated in the lead shield. Although bremsstrahlung photons can be generated in materials such as copper and steel, without the lead it will be significantly less and therefore would require less shielding. Therefore, the staff has determined, that specifying an equivalence to 18 cm of lead for the copper and steel top portion of the Marguerite 20 provides reasonable assurance that there is enough shielding to ensure that radiation levels do not exceed regulatory limits in SSR-6.

5.4 Flux-to-Dose Rate Conversion Factors The applicant uses the flux-to-dose-rate conversion factors for the ambient dose equivalent, H*(10), from the International Commission on Radiological Protection, Publication 74 Conversion Coefficients for use in Radiological Protection against External Radiation, (ICRP-74). The staff accepts the flux-to-dose-rate conversion factors from ANS/ANSI-6.1.1-1977. The ambient dose equivalent in ICRP-74 was formulated as an operational quantity for area monitoring meaning that it can be measurable from a detector. These conversion factors

have not been evaluated by the NRC staff and the staff continues to accept the conversion factors from American National Standards Institute (ANS/ANSI)-6.1.1-1977, , Neutron and Gamma-Ray Flux-to-Dose Factors, which more conservatively calculates the measurable dose rate. The staff compared the flux-to-dose-rate conversion factors between ANS/ANSI-6.1.1-1977 and that of H*(10) from ICRP-74 and found that the difference is as large as two orders of magnitude for lower energy photons (10 keV) and as much as 1.5 times higher for photons above 40 keV. The reason the conversion factors for ANS/ANSI-6.1.1-1977 are so much higher for lower energy photons is because the H*(10) conversion factors from ICRP-74 are evaluated assuming dose is deposited in a 10 mm International Commission on Radiation Units (ICRU) sphere. Lower energy photons deposit energy at a shallower depth. This is recognized by the Specific Safety Guide SSR-6 supporting documentation (SSG-26).

SSG-26 Paragraph 233.1 states that SSR-6 radiation levels are in terms of ambient dose equivalent for strongly penetrating radiation and directional dose equivalent for weakly penetrating radiation. General Safety Requirements Part 3 No. GSR Part 3, Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards, further defines the ambient dose equivalent as the dose equivalent produced at a recommended depth of 10 mm in the ICRU sphere and directional dose equivalent as the dose equivalent produced at a recommended depth of 0.07 mm in the ICRU sphere. GSR Part 3 defines weakly penetrating radiation to include photons of energy below about 12 keV, electrons of energy less than about 2 MeV, and massive charged particles such as protons and alpha particles.

The staff found that the flux-to-dose-rate conversion factors agree more between the ANS/ANSI-6.1.1-1977 and the directional dose equivalent H(0.07,0o) from ICRP-74 at energies below 30 keV.

Based on an estimate from Equation 5.11a in Cember, Introduction to Health Physics, 1996 (ISBN 0-07-105461-8), the fraction of incident beta energy estimated to be converted to photons is at an average of about 25 keV and a maximum of 150 keV. There would be some photons reaching the detector from lower energy bremsstrahlung gammas and gammas reduced in energy from scattering. Even though some of these photons may be of the energy where the flux-to-dose-rate conversion factors are non-conservative by 2 orders of magnitude, it is more likely that the photons reaching the detector will be the higher energy photons and higher energy photons will contribute more to the dose rate. The energy of these photons is where the flux-to-dose rate conversion factors used by the applicant underpredict the dose rate as compared to factors accepted by the staff by about a factor of 1.5. There is about an order of magnitude conservatism in the applicants calculated radiation level as compared to the SSR-6 surface limit. Considering this the staff found the use of the ambient dose equivalent flux-to-dose-rate conversion factors from ICRP-74 acceptable for this application.

5.5 Accident Conditions of Transport The applicant states that its model of the package under accident conditions is the same as that for routine and normal conditions of transport as the applicant does not model the upper and lower casing, and the top and bottom foam absorbers of the EDCE. The staff found this adequate for representing accident conditions as these are the components that would be damaged under accident conditions.

5.6 Radiation Levels The applicant calculated the maximum radiation level at the surface of the Manon using two different types of MCNP tallies. It used the F4 (cell flux) and F5 (detector flux). Since the two tallies are evaluated in different ways, the applicant compared the two, the staff found this conservative and acceptable. The highest surface radiation level was from the F4 cell flux tally and is 171 µSv/hr (0.171 mSv/hr) at the surface of the EDCE (limit 2 mSV/hr). The applicant did not calculate the radiation level at 1 meter from the package to demonstrate that it is capable of meeting the TI in SSR-6 Paragraph 523 (0.1 mSv/hr at 1 meter), however since the calculated surface limit is already so close to the 0.1 mSv/hr limit for 1 meter, and the nature of a radiation field is that it decreases proportional to the distance squared, the staff has reasonable assurance that the package will meet the TI requirement in Paragraph 523 of the SSR-6.

Comparisons of calculations at 1 meter versus the surface for other sources authorized by the French Certificate of Approval show that the radiation level decreases by almost an order of magnitude at 1 meter as compared to surface radiation levels (U-8021-NT-01 Rev. 1, Radioactive Release Study for the Casing For SV34, SV69 and Non-Removable Equipment.)

Using the same reasoning, the staff also found that the package will meet the accident condition radiation level in Paragraph 659(b)(1) which is 10 mSv/hr at 1 meter because the accident condition model is the same as that for the routine and normal conditions of transport model.

Similarly, because the model used by the applicant represents routine, normal and accident conditions, the staff concluded that the applicant also meets Paragraph 648(b) of the SSR-6 which states that under normal conditions of transport that the package not experience more than a 20% increase in the maximum radiation level.

5.7 Conclusion As discussed in the above paragraphs, the staff has reasonable assurance that the F-522 package meets the requirements in Paragraphs 526, 527, 648(b), 659(b)(1) in SSR-6. The staff recommends revalidation of French Certificate F/410/B(U)-96 Revision Ad for the Manon package with the conditions as discussed in this report.

5.8 Conditions of Revalidation The Marguerite 20 must contain 10 cm of lead surrounding the Sr-90 source on the sides and bottom. Above the source, the Marguerite 20 must have enough copper, steel and air to be equivalent to 18 cm of lead. The Marguerite 20 must further have 1.5 mm of steel surrounding the source on all sides.

6.0 CRITICALITY EVALUATION

There is no fissile material in the package, therefore a criticality evaluation is not required.

7.0 OPERATING PROCEDURES EVALUATION The Package User Manual in the safety analysis report include sections on package acceptance, loading, unloading, and pre- and post-shipment requirements. The operating procedures have specific measures to be taken prior to each shipment, including ensuring the correct shims are used for the corresponding RTG, installing the package closures and confirming that the lid screws are properly torqued, leak testing the lid and containment penetration seals, and taking radiation measurements.

8.0 ACCEPTANCE TESTS AND MAINTENANCE PROGRAM EVALUATION The acceptance test program includes: document examination; visual examination; and leak testing to ensure that the package is fabricated in accordance with the design approved in the French certificate. The maintenance program includes requirements for each shipment, after 15 cycles (or 3 years whichever is less), and after 60 cycles. The maintenance tests for each cycle, 15 cycles and 60 builds upon one another to ensure continued efficacy of the package design.

CONCLUSION Based on the statements and representations contained in the documents referenced above (see

SUMMARY

), the staff concludes that the Model No. Manon package meets the requirements of International Atomic Energy Agency Regulations for the Safe Transport of Radioactive Material, IAEA Safety Standards Series, No. SSR-6, 2012 edition.

Issued with letter to R. Boyle, Department of Transportation, on October 25, 2019.