ML23279A103
| ML23279A103 | |
| Person / Time | |
|---|---|
| Site: | Westinghouse |
| Issue date: | 10/27/2023 |
| From: | NRC/NMSS/DFM/FFLB |
| To: | Westinghouse Columbia Fuel Fabrication |
| Shared Package | |
| ML23279A099 | List: |
| References | |
| EPID L-2022-LLA-0177 | |
| Download: ML23279A103 (9) | |
Text
OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION 1
OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION SAFETY EVALUATION REPORT WESTINGHOUSE ELECTRIC COMPANY, LLC APPLICATION FOR TEMPORARY POSSESSION OF CERTAIN HEMATITE ASH DOCKET:
70-1151 LICENSEE:
WESTINGHOUSE ELECTRIC COMPANY, LLC
SUBJECT:
SAFETY EVALUATION REPORT: REVISION TO TEMPORARY LICENSE CONDITIONS FOR SAMPLING, ANALYSIS, AND DISPOSITION OF HEMATITE ASH MATERIAL PHASE II ABOVE LICENSE LIMITS (EPID L-2022-LLA-0177)
1.0 BACKGROUND
By cover letter dated December 2, 2022, Westinghouse Electric Company, LLC (Westinghouse or WEC) submitted a license amendment request to temporarily possess and store a limited quantity of Hematite ash in excess of its current possession limit of 5.0 weight percent (wt.%)
uranium-235 (235U) (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML22336A174). The request was for possession and storage of the material only and did not include any material processing.
In the first quarter of 2003, Westinghouse was in the process of decommissioning the Westinghouse Hematite site in Hematite, MO. Ash from the incinerator for uranium recovery was sent to the Columbia Fuel Fabrication Facility (CFFF) for processing. The ash has been in storage since that time and CFFF recently began a campaign to process all the ash from the Hematite site. During that process, as described in Nuclear Regulatory Commission (NRC)
Event Notification 56199, CFFF employees discovered that some bags from the Hematite site had labels stating the ash contents were above or statistically had the potential to be above the 5.0 wt.% 235U limit in Materials License SNM-1107 for CFFF. In total, nine drums containing ash potentially above the 5.0 wt.% 235U threshold were identified and segregated from the remaining Hematite drums and are currently stored in an intermodal transport container suspended off the ground on a flatbed trailer.
On May 5, 2023 (ML23094A158), the NRC granted Westinghouse a temporary license amendment to authorize the possession and storage of a limited quantity of Hematite ash material in excess of its possession limit of 5.0 wt.% 235U (Phase I of the WEC Hematite Ash campaign).
As a follow-on action to the temporary license amendment for Phase I, WEC requested, via letter dated June 9, 2023 (ML23160A261), a modification to the temporary license amendment and associated temporary license conditions S-19 and S-20 to authorize the handling, sampling, analysis and down-blending, as necessary, of the ash material to less than 5.0 wt.% 235U (i.e.,
Phase II). In so doing, Westinghouse would down-blend the material to within the current SNM-1107 possession limits.
The staff reviewed Westinghouses license application and its supporting documentation, including CSE-4-J, Criticality Safety Evaluation (CSE) for Processing Suspect >5 wt.% Ash (ML23160A264, non-public), which documents the criticality safety basis for the transfer of
OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION 2
OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION Hematite ash from their current location in 55-gallon drums to the uranium recycle and recovery services (URRS) Sifting/Cleaning Hood (RH-1070) wherein sampling, down-blending, and loading into polypaks will be performed. Staff also reviewed supplemental information provided by Westinghouse on August 18, 2023, in support of its application (ML23230B302)
(supplemental information).
The purpose of this review is to determine whether the proposed activities will be conducted such that adequate protection for the health and safety of workers and the public against criticality hazards is reasonably assured, and whether the proposed activities will be conducted such that subcriticality is assured under normal and all credible abnormal conditions.
Additionally, the staff also determined whether the requested revision to the temporary license conditions for sampling, analysis, and disposition of the drums of incinerator ash referenced in the submittal will not result in any significant impact from a safeguards perspective. The staff documents its review below.
2.0 REGULATORY REQUIREMENTS The NRC staff conducted its review of the licensees request to ensure that the statements and commitments described in the submittal are consistent with the applicable requirements of 10 CFR Part 70, including:
§70.22, Contents of applications;
§70.23(a)(6), Requirements for the approval of applications;
§70.24, Criticality accident requirements;
§70.61, Performance requirements;
§70.62, Safety program and integrated safety analysis; and
§74.31, Nuclear material control and accounting for special nuclear material of low strategic significance.
The NRC regulatory guidance for an acceptable material control and accounting (MC&A) program applicable to Category III fuel fabrication facilities is NUREG-1065, Acceptable Standard Format and Content for the Fundamental Nuclear Material Control (FNMC) Plan Required for Low-Enriched Uranium Facilities, Rev. 2 (ML031340288). The NUREG is divided into separate chapters for each of the program areas listed with associated commitments and acceptance criteria for each program area. Additionally, the NRC staffs criticality safety review was conducted in accordance with the applicable acceptance criteria in Chapter 5, Nuclear Criticality Safety, of NUREG-1520, Standard Review Plan for Fuel Cycle Facilities License Applications, Rev. 2, (ML15176A258) as well as applicable portions of NUREG/CR-6698, Guide for Validation of Nuclear Criticality Safety Calculational Methodology (ML050250061).
3.0 MATERIAL CONTROL AND ACCOUNTING As specified in 10 CFR 70.22(b), each licensee authorized to possess and use special nuclear material (SNM) in a quantity exceeding one effective kilogram must provide a full description of its program for MC&A of such SNM to show how compliance with applicable requirements of 10 CFR part 74, Material Control and Accounting of Special Nuclear Material, will be accomplished. Regulations in 10 CFR part 74 subpart B, General Reporting and Recordkeeping Requirements, and in 10 CFR 74.31, Nuclear Material Control and Accounting for Special Nuclear Material of Low Strategic Significance, apply to the establishment of an MC&A program for Category III fuel fabrication facilities. The requirements in 10 CFR 74.31
OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION 3
OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION cover the specific MC&A program capabilities needed to establish an acceptable MC&A program. Category III fuel fabrication facilities are required to have a fundamental nuclear material control plan (FNMCP) describing how the performance objectives in 10 CFR 74.31(a),
the system capabilities of 10 CFR 74.31(c), and the recordkeeping requirements of 10 CFR 74.31(d) will be met. Additionally, 10 CFR 70.23(a) contains requirements for the approval of applications, and subparagraph (6) states that where the applicant is required to submit a summary description of the fundamental material controls provided in his procedures for the control and accounting for special nuclear material pursuant to §70.22(b), the applicants proposed controls [must be] adequate.
The NRC staff reviewed the June 2023 submittal for specific MC&A impacts of the request for modification of the temporary license conditions to authorize handling, sampling, analysis and down-blending of the subject incinerator ash as referenced in the submittal letter. The licensee provided an outline of the sampling and disposition process for the ash material potentially greater than 5.0 wt. % 235U. Additionally, the licensee provided draft revisions to existing operating procedures that incorporate the sampling and disposition activities as discussed in the process outline.
The NRC staff reviewed the currently approved FNMCP, Revision 44, dated July 9, 2019 (ML19190A152), which is required by 10 CFR 70.22(b). The FNMCP describes the licensees MC&A program and includes the practices in use for all the SNM possessed under the license, including the procedures for incinerator ash. Chapter 2 provides a general overview of the MC&A system, covering receipts, shipments, statistics, inventory, records, and reports. Chapter 4 describes the various measurement systems and measurement control practices for all SNM in the licensees possession, including sampling systems and analytical determinations. Chapter 6 discusses the item control program, including nuclear material receipt and entry into the item control program, in-plant handling aspects, and item control records. Chapter 9 describes the recordkeeping system.
Based on its review of the application, FNMCP, and the supplemental information (ML23230B202), the NRC staff finds that the licensees plan and procedures for handling, sampling, analysis and down-blending of the incinerator ash is consistent with the existing MC&A program as described in the FNMCP and is adequate to ensure the MC&A requirements in 10 CFR 74.31(a), (c), and (d) continue to be met. The NRC staff therefore finds there is reasonable assurance that the licensees existing MC&A program will continue to detect and protect against the loss, theft, or diversion of SNM that the licensee possesses, stores, and utilizes at its facility, and the requirement of 10 CFR 70.23(a)(6) for approving applications has been met.
4.0 CRITICALITY SAFETY The requested amendment involves the handling, sampling, analysis and down-blending of a limited quantity of Hematite ash in excess of the licensees current possession limit of 5.0 wt.%
235U. Nine 55-gallon drums containing incinerator ash in excess of 5.0 wt.% 235U were shipped from the Hematite site to WECs CFFF facility in 2003. Although the average enrichment of the material contained in each drum is less than 5.0 wt.% 235U, each drum contains two or more items (i.e., bags), some of which contain material in excess of 5.0 wt.% 235U or have the potential to exceed 5.0 wt.% 235U when accounting for statistical uncertainty. The individual item enrichment and 235U mass, as well as the average drum enrichment and total drum 235U mass are described in enclosure 2 of the Phase I application (ML22336A174), reproduced in part below.
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OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION Drum Contents Drum Identifier Item wt.% 235U Item Mass (g 235U)
Total Mass (g 235U)
Enrichment Average (wt.% 235U) 5.17 37 4.1 192 HO29 4.084 33 262 4.222 5.028 37 4.48 81 H033 4.291 52 170 4.526 5.02 42 4.4 203 4.108 4
H058 4.07 85 334 4.373 5.01 43 4.46 86 4.09 3
H104 4.04 117 250 4.326 5.00 105 4.58 90 H032 4.521 58 253 4.73 5.00 252 H096 4.1 56 308 4.809 4.999 25 4.58 70 4.52 22 H022 4.06 36 153 4.498 4.96 61 4.41 128 H023 4.26 125 315 4.443 4.957 23 4.15 45 H068 4.06 246 314 4.128 The individual item enrichment ranges from 4.04 to 5.17 wt.% 235U, with the total drum enrichment ranging from 4.128 to 4.809 wt.% 235U. The individual item mass ranges from 3 to 252 grams 235U, with total drum mass ranging from 153 to 334 grams 235U. The maximum quantity in any drum does not exceed 334 grams 235U. The total 235U mass of all nine drums is approximately 2.36 kilograms.
WEC stated that the current configuration of the drums is bound by an existing nuclear criticality safety evaluation, CSE-16-F, Criticality Safety Evaluation (CSE) for Floor Storage of Special Nuclear Material, which demonstrates that the drums do not present any credible criticality hazard.
The staff reviewed CSE-4-J, Criticality Safety Evaluation (CSE) for Processing Suspect >5 wt.% Ash (ML23160A264, non-public), which documents the criticality safety basis for the transfer of Hematite ash from their current location in 55-gallon drums to the URRS
OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION 5
OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION Sifting/Cleaning Hood (RH-1070) wherein sampling, down-blending, and loading into polypaks will be performed.
Normal Conditions Under normal conditions, 55-gallon drums containing the Hematite ash will be brought into the enclosed Dock 3 staging area. The drums will then be moved to an unloading station within a raised floor area in Dock 3. The lid of the drums will be removed and each bag containing ash will be weighed using a calibrated scale and inspected for any presence of moderating material.
Only one drum lid will be permitted to be removed at a time, and the drum will be lidded when not actively in use. Each bag of ash with contents potentially greater than 5.0 wt.% 235U will be brought into the hood one at a time. Duplicate samples will be taken from each bag, and each bag will be resealed and returned to its parent container. The Chemistry Laboratory will analyze the sampled ash for uranium isotopic compositions to verify enrichment. After receipt of the isotopic analyses, nuclear criticality safety (NCS) and URRS staff will determine the disposal path for the material. Any material with analytical results greater than 5.0 wt.% 235U will be blended with a predetermined amount of lower assay material from the same shipping container into polypaks. After mixing of the blended polypaks, duplicate samples will be taken and sent to the Chemistry Laboratory for isotopic analysis. Following confirmation of the analyses by NCS and URRS staff, the blended material will be moved to the URRS C-4 Dissolver process for dissolution under existing URRS procedures.
Down-blended ash will be processed using existing licensed activities or processes (i.e.,
storage, dissolution, and uranium recovery) and will be below the SNM-1107 possession limit of 5.0 wt.% 235U. Consequently, activities associated with the processing of down-blended ash are bound by the existing SNM-1107 license and were, therefore, not evaluated by NRC staff in this report. Criticality hazards associated with inadvertent criticality in the 55-gallon drums containing Hematite ash were evaluated by NRC staff as part of Phase I of the Hematite ash campaign as documented in NRC staffs evaluation of Phase I, Safety Evaluation Report: Request to Temporarily Possess a Limited Quantity of Hematite Ash Above License Limits (EPID L-2022-LLA-0177) (ML23094A159) and were found to be not credible. Therefore, criticality hazards associated with 55-gallon drums containing Hematite ash were likewise not evaluated by NRC staff in this report. The staffs review documented herein focused on the criticality hazards associated with the handling, sampling, and down-blending of the ash material.
It is important to note that each drum is limited to 500 grams 235U, which is below the single parameter limit for uranium systems of any material composition per ANSI/ANS-8.1, Nuclear Criticality Safety in Operations with Fissionable Material Outside Reactors (available for purchase from ANS), as endorsed by NRC Regulatory Guide (RG)-3.71, Nuclear Criticality Safety Standards for Nuclear Materials Outside Reactor Cores, Rev. 3 (ML18169A258). This, combined with the licensees administrative restriction to allow only one drum to be unlidded and processed at a time, ensures that the normal conditions associated with the handling, sampling, and down-blending of Hematite ash will not involve sufficient mass for criticality. For these reasons, the staff determined with reasonable assurance that the activities associated with the requested amendment will be subcritical under normal conditions.
Credible Abnormal Conditions Although normal conditions do not involve a sufficient mass for criticality, credible abnormal conditions exist in which higher quantities of mass could be introduced. However, given the
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OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION enrichment of the material (highest enrichment of 5.17 wt.% 235U), a concurrent moderation upset would also be required for criticality to occur.
The licensees analysis identified and considered credible abnormal conditions involving moderation upsets, including two bounding sequences: 1) the presence of moderating material in a bag containing Hematite ash outside of the URRS Sifting/Cleaning Hood (RH-1070), and
- 2) the presence of moderating material inside the RH-1070 hood. Both bounding sequences included concurrent mass upsets.
Moderating Material Present Outside of RH-1070 The licensee imposed three administrative controls to limit mass and two administrative controls to ensure that significant amounts of moderating material are not introduced. A description of each of these controls is provided in enclosure 2 of the Phase II application (ML23160A262, non-public).
The staff performed an independent confirmatory analysis using the SCALE 6.0/KENO-VI Monte Carlo N-Particle application with various continuous energy cross-section libraries. In its analysis, the staff considered a 5.5 wt.% 235U uranium dioxide (UO2)-water mixture consisting of a fully reflected spherical geometry.
Figure Homogeneous U(5.5)O2-H2O Mixtures The staff determined that a minimum of 22 liters of water would be required for criticality to occur, which corresponds to a uranium mass of more than 45 kilograms U. For the minimum critical mass (i.e., optimum moderation), more than 34 kgs U would be required for criticality, which corresponds to more than 40 liters of water. The staff determined that such a volume of moderator would be easily recognized by a trained operator and multiple upsets for both mass and moderation would be required in order for criticality to occur. Due to the licensees administrative controls on mass, the staff considers it unlikely that sufficient mass for criticality would be present; however, if a mass upset were to occur, the staff considers it further unlikely that the required quantity of moderation would be present concurrent with a significant mass upset given the administrative controls the licensee has imposed on moderation.
10 100 1000 10 100 1000 Homogeneous U(5.5)O2-Water Mixtures Critical Mass (kg U)
Moderator Volume (L H2O)
OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION 7
OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION The licensee also considered sources of moderation due to roof or piping leaks, as well as from firefighting efforts in the event of a fire. To limit the likelihood of the introduction of significant amounts of moderation due to these sources, the licensee also credited controls on its fire protection program and structural integrity.
The staff determined that the additional controls for moderating material present outside of RH-1070 (enclosure 3 of Phase II application, ML23160A264, non-public) are sufficient to limit the likelihood of a mass upset concurrent with an introduction of significant amounts of moderation such that at least two independent, concurrent, and unlikely changes in process conditions would be required in order for criticality to be possible (i.e., satisfies the double contingency principle as stated in ANSI/ANS-8.1-2014, and endorsed by RG 3.71 as cited above). The staff also determined that the aforementioned controls are sufficient to assure subcriticality under the credible abnormal condition of moderating material being present outside of the RH-1070 hood.
Moderating Material Present Inside RH-1070 Similar to the accident sequence involving moderating material present outside of the RH-1070 hood, firefighting efforts or roof/pipe leaks may introduce moderation while the ash material is inside of the RH-1070 hood. The primary difference between this accident sequence and the sequence involving moderation present outside of the hood is that the ash material may be located outside of its bags/containers while inside the hood due to processing. In addition to only one drum being permitted to be in process in Dock 3 at a time, the licensee imposed a restriction on mass in the RH-1070 hood to no more than two bags of ash at a time. To limit the likelihood of an introduction of significant amounts of moderation, the licensee credited its fire protection program and associated restrictions on firefighting techniques that limit the amount of moderating material introduced due to firefighting efforts, as well as controls associated with dissolver area roof and piping integrity. The licensee also imposed a control to require that containers in the RH-1070 hood be covered or resealed before being left unattended.
As previously discussed, the staff determined that the volume of moderator required for criticality would be easily recognized by a trained operator, and that multiple upsets for both mass and moderation would be required in order for criticality to occur. Due to the licensees administrative controls on mass, the staff considers it unlikely that sufficient mass for criticality would be present; however, if a mass upset were to occur, the staff considers it further unlikely that sufficient moderation would be present concurrent with the mass upset given the administrative controls the licensee has imposed on moderation. The staff determined that the aforementioned controls are sufficient to limit the likelihood of a mass upset concurrent with an introduction of significant amounts of moderation such that at least two independent, concurrent, and unlikely changes in process conditions would be required in order for criticality to be possible (i.e., satisfies the double contingency principle). The staff also determined that the aforementioned controls are sufficient to assure subcriticality under the credible abnormal condition of moderating material being present inside of the RH-1070 hood.
The licensees overall NCS program was evaluated by NRC staff as documented in Chapter 5.0 of NRC Safety Evaluation Report (SER), Safety Evaluation Report: Renewal of License SNM-1107 for Westinghouse Electric Company, LLC, Hopkins, South Carolina - Docket Number 70-1151 (ML22207B617 hereafter referred to as SER for SNM-1107 License Renewal). In that report, the staff concluded that WECs NCS program and commitments related to technical practices were adequate to meet the requirements of 10 CFR Part 70, including 10 CFR 70.61(d).
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OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION Regarding the pending request related to Phase II of the Hematite Ash campaign, the staff reviewed the abovementioned controls and determined that the licensees analysis and imposition of controls is consistent with the licensees NCS program as described in Section 6.0 of the SNM-1107 license application. Furthermore, the staff determined that the controls are sufficient to satisfy the double contingency principle and are sufficient to assure subcriticality under normal and credible abnormal conditions, consistent with the staff conclusions as documented in the SER for SNM-1107 License Renewal (ML22207B617). For these reasons, the staff concludes with reasonable assurance that the requested activities satisfy the applicable requirements of 10 CFR Part 70, including the performance requirements of 10 CFR 70.61.
Changes to Integrated Safety Analysis Summary The staff reviewed the changes to the licensees Integrated Safety Analysis (ISA) Summary and determined that no changes were made to the licensees existing ISA methodology. The staff determined that the changes merely align the ISA Summary with the activities associated with the requested amendment and are, therefore, acceptable.
5.0 ENVIRONMENTAL REVIEW The amendment changes a requirement with respect to a materials license issued under 10 CFR Part 70, identified in 10 CFR 51.60(b)(1), and which is considered administrative, organizational, or procedural in nature. The NRC staff determined that the changes addressed by this amendment will not result in any significant change in effluents released offsite or any significant increase in individual, or cumulative occupational radiation exposure. Additionally, the amendment will not result in any construction impacts or any significant increase in the potential for consequences from radiological accidents. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(11). Pursuant to 10 CFR 51.22(b),
no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
6.0 CONCLUSION
Based on the review of the submittal, the FNMCP, and the supplemental information, the NRC staff has determined that the modification of the temporary license conditions for sampling, analysis and disposition of the subject drums will not result in any significant impact from a safeguards perspective. The licensees MC&A program as described in the approved FNMCP will continue to provide reasonable assurance that loss, theft, or diversion of SNM will be detected and protected against. The NRC staff finds that the licensee continues to meet the applicable MC&A requirements in 10 CFR Part 74, the 10 CFR 70.23(a)(6) requirement for approving applications has been met, and therefore approves the modification of the temporary license conditions to sample, analyze and disposition this specified material:
- The request is limited to the storage of the nine drums of incinerator ash referenced in the submittal;
- The nine drums are controlled in accordance with the FNMCP and associated site procedures; and
- The nine drums will remain segregated from other material and handled in accordance with the procedures specified in the June 9, 2023 application, as supplemented.
Based on the review discussed in this report, the NRC staff concluded that the licensees request provides reasonable assurance of subcriticality under normal and all credible abnormal
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OFFICIAL USE ONLY - SECURITY-RELATED INFORMATION conditions, provides reasonable assurance of adequate protection against the risk of criticality accidents, and otherwise satisfies the applicable requirements of 10 CFR Part 70. Two temporary license conditions (S-19 and S-20) are amended to permit sampling, analysis and disposition of the subject Hematite ash material. The two temporary license conditions are revised as follows:
License Condition S-19:
The licensee shall use the methods described in the June 9, 2023, application to sample, analyze and disposition the 55-gallon drums containing Hematite ash in excess of 5.0 wt.% 235U.
License Condition S-20:
The licensee shall maintain at least 12 inches edge-to-edge spacing between 55-gallon drums containing Hematite ash in excess of 5.0 wt.% 235U and all other fissionable material during the sampling, analysis and disposition of this material.
PRINCIPAL CONTRIBUTORS JTobin, DFM SAni, DFM JMunson, DFM