ML20195H454
| ML20195H454 | |
| Person / Time | |
|---|---|
| Site: | Portsmouth Gaseous Diffusion Plant, Paducah Gaseous Diffusion Plant |
| Issue date: | 03/01/1999 |
| From: | Toelle C UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | Pierson R NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| Shared Package | |
| ML20195H463 | List: |
| References | |
| GDP-99-0043, GDP-99-43, GPD-99-43, TAC-L32009, TAC-L32067, NUDOCS 9906170055 | |
| Download: ML20195H454 (18) | |
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March 1,1999 -
GDP 99-0043 Mr. Robert C. Pierson Chief, Special Projects Branch Division of Fuel Cycle Safety and Safeguards, NMSS Attention: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Paducah Gaseous Diffusion Plant (PGDP)
Portsmouth Gaseous Diffusion Plant (PORTS)
Docket Nos. 70-7001 and 70-7002 USEC Response to Request for AdditionalInformatior. (RAI)- Criticality Accident Alarm System (CAAS) Monitoring Exclusion Requests (TAC No L32009 and TAC No. L32067)
Dear Mr. Pierson:
The purpose of this letter is to respond to the NRC's December 4,1998 letter, TAC No. L32009
- and TAC No. L32067, requesting additional information concerning USEC's request for exclusion of areas within the USEC leased areas from CAAS monitoring. provides a response to your staff's questions or requests concerning the Portsmouth Gaseous Diffusion Plant (GDP) CAAS exclusion request. Enclosure 2 provides a response to your staffs questions or requests concerning the Paducah GDP CAAS exclusion request.
Enclosures 3 and 4 provide updated documents that were originally submitted as part of the original CAAS exclusion request for the PGDP and PORTS plants, respectively.
Should you have any questions related to this subject, please contact Marc Klasky at (301) 564-3408. There are no new committments contained in this submittal.
Sincerely, S. A.
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Steven A.Toelle Nuclear Regulatory Assurance aad Policy Manager 6Dp 9906170055 990301 ~i9 PDR ADOCK 07007001[#
E PDR 6903 Rockledge Drive, Bethesda, MD 20817-1818 Telephone 301564-3200 Fax 301-564-3201 http://www.usec.com Offices in Livermore, CA Paducah, KY Portsmouth, OH Washington, DC L
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g, Mr. Robert Pierson
. Merch 1,1999 GDP 99-0043, Page 2
Enclosures:
1.
Portsmouth Response to NRC RAI dated December 4,1998 2.
Paducah Response to NRC RAI dated December 4,1998 3.
Paducah Updated References to April 9,1996 and August 1996 submittal 4.
Portsmouth Updated References to May 22,1996 submittal f
cc: Mr. Robert C. Pierson, NRC IIQ NRC Region 111 Office NRC Resident inspector-PORTS NRC Resident inspector-PGDP L
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l GDP 99-0043 Portsmouth Response to RAI Page 1 of 6 -
Q1 (NRC 12/4/98 Letter)
Please provide on the docket all updates that may have been made to the documents submitted aspart ofthe original CDS exemption requests submittedin 1996. During the site visits, NRC staf were made aware ofrevisions to the technicalsupport documents, including t evised building listings requiring CDS exemption, that were notpart ofthe original submittals.
Response
The original submittal dated May 22,1996 contained references which listed / justified the areas of the plant to be excluded from CAAS coverage. The accompanying Tal,le presents these references and indicates whether the document was revised subsequent to the original submittal. Updated references are provided in Enclosure 4 of this submittal, Report Updated Yes/No Criticality Accident Alarm System Coverage and &clusions, dated December 1998 Yes and Addendum dated February 26,1999 Justificationsfor &cluding UF, Cylinder Storage Yardsfrom Criticality Accident Yes Alarm System Coverage, dated March 1997.
Analysis ofthe Proposed Relocation ofthe Neutron Criticality Clusters in the Process No Buildingsfor the Portsmouth Gaseous Difusion Plant, dated January 1994 Veri ication ofCriticality Accident Alarm System Detector Locationsfor theX-326 No f
Process CellFloor, dated August 1995.
Analysis ofCriticality Accident Alarm System Coverage in IheX-700, %705, and%
No 720 Facilities, dated December 1995 Analysis ofCriticality Accident Alarm System Coverage ofthe X-744G, X-744H, X-No 342/344A andX-343 Facilities at the Portsmouth Gaseous Difusion Plant, dated September 1995 1
Analysis ofCriticality Alarm System Response to an Accidental Criticality outside the No Cascade Process Buildings at the Portsmouth Gaseous Difusion Plant, dated July l994
& amination ofCriticality Accident Alarm Coverage on the Operating Floors ofthe Yes X-333, X-330, andX-326 Facilities at the Portsmouth Gaseous Difusion Plant, dated 1
March 1997 An hamination ofCriticality Accident Alarm Coverage ofIheX-710, X-760, No Buildings and the North Halfofthe X-7745-R Storage Pad, dated January 1996
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i GDP 99-0043 Portsmouth Response to RAI Page 2 of 6 Q2 (NRC 12/4/98 Letter)
For the buildings / areas whichyou are requesting CAAS exemption, please indicate which ones are directly connected to equipment andprocesses that may contain greater than a safe mass of uranium. Describe the controls that are relied upon to ensure that such quantities ofuranium are not transferable to the unmonitoredareas during allnormalandcredible abnormalplant conditions.
For those buildings / areas requiring CAAS exemption that are not connected to areas processing these quantities or that have been physically disconnectedfrom areas processing these, please describe the controls that are relied upon to ensure connections are not erroneously established.
For example, the Fluor!ne Storage Building, X-342B, at the Portsmouth Site contains largefluorine supply tanks, which are connected to the cascade. USEC mustprovide reliable controls, which prevent the backflow ofsigm'ficant quantities ofuranium to these storage tanks or demonstrate that
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such backflow can not result in a critical excursion.
i Response (Part A):
The following buildings / areas, for which USEC is requesting an exclusion to CAAS coverage, are directly connected to equipment / processes that may conmin creater than a safe mass of uranium:
1 A.
The plant nitrogen distribution system (X-232A)
The plant nitrogen system is designed to generate and distribute nitrogen for use on site. The nitrogen is directly connected to cascade equipment (i.e., compressor seal system). The nitrogen distribution header is maintained at a normal pressure of 55 psig (see SAR Section 3.4.3.2.3). Reducing stations in the process buildings supply nitrogen at a reduced pressure (X-333 and X-330 at 10 psig, and X-326 at 5 psig). The backflow of UF into the nitrogen 6
distribution system is not credible under normal operating conditions due to the pressure difference between the cells and nitrogen distribution system.
In the event of a loss of nitrogen pressure, the automatic cross-over to air occurs when nitrogen pressure drops below 8.0 psig in X-333 and A-330 or 4.5 psig in X-326.
Additionally, low nitrogen header pressure alarms (audible and visual) alarm in the Plant 1
Control Facility (PCF) and Area Control Rooms (ACRs). Personnel take appropriate actions to maintain the cell seal feed. Based on the system design and operational necessary of l
maintaining cell seal feed there are no credible abnormal plant conditions that could allow i
transfer of uranium to unmonitored areas.
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I GDP 99-0043 Portsmouth Response to RAI Page 3 of 6 B.
The plant dry air distribution system (X-2328)
The plant dry air system is designed to generate and distribute dry air for use on site. The air distribution system is directly connected to cascade equipment (i.e., compressor seal system, to purge process equipment, substitute for nitrogen during a nitrogen distribution system failure, and process system instruments). The dry air distribution header is maintained at a nominal pressure of100 to 110 psig (see Section 3.4.4.1 of the SAR). Where necessary, dry air is supplied at lower pressures through the use oflocal pressure reducing stations. The backflow of UF into the dry air distribution 5,ystem is not credible under 6
normal operating conditions due to the pressure difference between the process equipment and dry air distribution system.
In the advent of a loss of pressure in the dry air distribution header, additional compressors automatically start (95 psig at X-330 air plant and 88 psig at X-326 air plant). If the header pressure continues to lower valves DA-3 and DA-8 close (65 psig). These valves isolate the outer loop (administrative and auxiliary buildings) from the inner loop (facilities vital to continued cascade operation). Additionally low pressure alarms actuate in the PCF and ACRs. Personnel take appropriate actions to maintain the pressure in the system. Based on the system design and operational parameters of the dry air distribution system there are no credible abnormal plant conditions that could allow transfer of uranium to unmonitored areas.
C.
The Fluorine Storage Building (X-3428) and fluorine distribution system (X-232F)
Clarification: The fluorine storage tanks in X-342B are not directly connected to the cascade.
The fluorine storage tanks are connected to a metering station in X-342A then to the PG return and back iron headers to the rest of plantsite.
The fluorine storage tanks and distribution system are operated in accordance with Plant Procedures. During normal operations, the fluorine storage tanks and distribution system are operated above atmospheric pressure. This operation is controlled by the procedure XP4-TE-FG2640 " Operation of the Fluorine Metering Station and Distribution System". The actual pressure / flow rate of fluorine in the distribution system is determined by the Cascade Controller based on the needs of the plant.
During normal operations, the fluorine distribution system and fluorine storage tanks in X-342B are always above atmospheric pressure and the cell pressure in the cascade, it is not possible for UF. to enter the fluorine distribution system and then travel to the fluorine storage tanks in X-3428.
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GDP 99-0043 Portsmouth Response to RAI Page 4 of 6 Once every 10 years, the fluorine storage tanks in X-342B are inspected. Prior to the inspection, the amount of fluorine in the tank is reduced as much as possible through normal usage. The fluorine tank is then connected to the Evacuation Booster Station (EBS) system, if available, to reduce the pressure in the fluorine tank further (Cascade Controller coordinates the valving lineup). This is the only time that the fluorine storage tank is below atmospheric pressure. If the EBS system is not available for this purpose, the fluorine is vented from the storage tanks in a controlled manner.
The EBS system is used to evacuate one component / item at a time. This is a SAR requirement and is flowed down into the EBS operating procedures. Thus when the EBS is used to evacuate a fluorine storage tank, the valving line up being controlled by the Cascade Controller, there is no path for UF to reach the fluorine storage tank. In the event of a 6
valving line up error connecting the EBS to a cell (containing UF ) and a fluorine storage 6
tank, the UF would flow toward the EBS pump and not the fluorine storage tank. There are 6
no credible abnormal events that would allow cascade equipment containing UF to be 6
connected to a fluorine storage tank below atmospheric pressure. Thus the backflow of UF6 to a fluorine storage tank is not credible since there is no pressure differential that would allow this to occur.
There are no credible abnormal events that would allow UF to reach the fluorine storage 6
tanks in X-342A. Thus there are no credible methods for UF to enter the fluorine storage 6
tanks in X-342B during normal or abnormal operations.
Resptmse 2 (Part B)
To ensure that plant modifications are not performed in a manner that would enable fissile material j
to be erroneously transferred to unconnected areas of the plant, for which a CAAS exclusion is being requested, a Configuration Management Program has been established. A description of this Program is presented in SAR Section 6.3.5 " Physical Plant Change Control and Configuration Management". SAR Section 6.3.5.2.4 " General Modification Process" describes the elements of the change control process.
1 The modification design control process requires a modification team for all modifications to Q, AQ and AQ-NCS structures, systems and components (SSCs). NCS is represented on every modification team until it is determined NCS is not affected by the modification. NCS participation is mandatory for all modifications dealing with fissile material operations. All modifications to Q, AQ and AQ-NCS SSCs are also reviewed by Nuclear Safety Analysis against the SAR accident analysis and approved Nuclear Criticality Safety Evaluations / Approvals.
Finally, tL:se modifications must be reviewed and approved by the Plant Operations Review Committee before implementation. Furthermore, the Nuclear Criticality Safety (NCS) program requires each functional manager to ensure that operations in their area that involve, or could potentially involve fissile
F GDP 99-0043 Portsmouth Response to RAI Page 5 of 6 material, are identified and evaluated for nuclear criticality safety before initiation of the operation.
The NCS program procedure notes that this includes processes that may inadvertently involve fissile material due to a process upset condhion.
Q3 (NRC 12/4/98 Letter)
Please describe the measures (e.g., posting, training, controlled access, etc.) that will be used to control exempted building / areas used to store non-fissile material /equipmentfrom containing quantities offissile material such that a critical excursion is not possible.
Response
Workers at the Portsmouth Gaseous Diffusion Plant are required to attend a General Employee Training (GET) class. GET training and/or testing is required every two years. This training includes general NCS training which informs the personnel of criticality concerns and the potential for criticality accidents. This class also explains the differences between process buildings / areas, 235 235 where uranium is enriched to 1% or higher in U and where there is 15 grams or more U, as well l
as non-process buildings / areas, where no uranium is allowed. All employees / workers are instructed to inform the Plant Shift Supe intendent (PSS) of any container or pieces of equipment found 235 235 containing material exceeding 1% or higher U, and 15 grams or more U in non-process buildings / areas without moving it. The PSS then ensures that the object is examined and moved if necessary.
In addition to GET training there is job specific training. The groups (e.g., Waste Management, Uranium Material Handling, Cascade Operations, Environmental Samplers and Lab personal) that move material 'oetween buildings receive additional training. This training emphasizes the l
importance of transporting the fissile material from point of receipt to its destination in a direct manner. It discusses the definition of fissile material, explains the parameters associated with criticality safety, and explains the application of these principles. In addition, this training covers l
personnel responsibilities related to criticality safety including obtaining the appropriate approvals l
prior to performing fissile material operations.
To ensure compliance with the NCS program requirements specified in the Procedures and Training Organization, walk-throughs and surveillances are performed by NCS, plant management, and the Safety, Safeguards, and Quality Organization. These walk-throughs and surveillances are performed in part to ensure that operations involving uranium enriched to I wt. percent or higher and 15 grams i
or more of 235U have been reviewed and approved by NCS, as well as to verify that conditions have not been altered to adversely affect NCS. This review and approval process includes compliance with CAAS requirements.
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Paducah Updated References to April 9,1996 and August 15,1996 submittals 1
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GDP 99-0043 Portsmouth Response to RAI Page 6 of 6 Q4 (NRC 12/4/98 Letter)
For the Portsmouth site, please identify all areas that are required to be monitored by a CAAS, but where CAASalarm audibility may not be adequate. For example, provide the measures relied i
upon to ensure adequate CAAS audibility in the cascade cell enclosuresfor all cell operational modes.
Response
There are no identified locations within the 12 rad boundary of a CAAS cluster for which the CAAS alarm is not audible, including the cell housings. Previously identified areas ofinaudibility at PORTS were corrected in response to Compliance Plan Issue #44. This issue was completed in July of1998.
An Industrial Ilygiene sound survey on the cascade cell floor indicated that within the housing of an operating cell the CAAS alarm was audible, for all cell operational modes, when personnel enter the cell in accordance with the Confined Space Program. The Confined Space Program requires that the housing door remain open in order to facilitate communication with the confined space attendant and therefore not only will the person (s) entering the cell housing be able to hear the CAAS alarm but will also have the added assurance as a result of the attendant being present and in direct contact with them should there be a CAAS alarm.
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Q1 (NRC 12/4/98 Letter)
Pleaseprovide on the docket all updates that may have been made to the documents submitted aspart ofthe original CAAS exemption requests submitted in 1996.
Response 1 The submittals dated April 9,1996 and August 15,1996 contained references which listed / justified the areas of the plant to be excluded from CAAS coverage. The accompanying Table presents these references and indicates whether the document was revised subsequent to the original submittal.
Updated references are provided as part of this RAI submittal.
Report Revised Yes/No T J. Cahill, Justi/Ication That Operations With Less Than 13 Grams "UDo Not Yes t
Require a Nuclear Criticality Safety Approval (NCSA) or a Criticality Accident Alarm System (CAAS), KY/G-632, Rev.1 March 1997.
G. R. Smolen, et al, Justificationfor No Criticality Alarm Coveragefor Areas With No Uranium Enriched to Less Than One Weight Percent U at the Paducah Gaseous Difusion Plant, KY/S-255, February 1996. (No change)
G. R. Smolen, Criticality Accident Alarm Coverage ofthe Interbuilding Tie Lines at No the Paducah Gaseous Difusion Plant, KY/G-578, February 1996. (No change)
R. J. Winiarski ir., NCS Evaluationfor the Drain System in the C-710 Facility at the Yes Paducah Gaseous Digusion Plant, CSA No. 1493-25, Rev. 2, March 1997 C. S. Miller, Justificationfor Not Having Criticality Alarm Coveragefor the C-726 No Sandblast Facility, KY/S-280, November 1995. (No change)
Yes Safety Solutions, Inc., Justificationfor Excluding UF, Cylinder Storage Yardsfrom Criticality Accident Alarm Coverage, KY/S-27i, Rev. 2, March 1997.
I Safety Solutions, lnc., TechnicalJusthficationfor the Exemption ofC-746-A C-733, Yes C-754. C-734-A, C-333, and C-737 Waste Storage Facilitiesfrom Criticality Alarm Requirements, KY/S-267. Rev. 2, March 1997.
G. R. Smolen, et al, Criticality Accident Alarm Detector Placement and Coverage at No the Paducah Gaseous Difusion Plant, KY/S-255, February 1996. (No change) l i
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GDP 99-0043 Paducah Response to RAI Page 2 of 7 In addition, PGDP has identified two additional facilities which were inadvertently left off of the initial request. These two facilities and thejustification for their exclusion from CAAS coverage are provided below:
Facility Facility Name or Function Type of Construction Justification C-727 90-Day Storage Area Prefabricated Metal
<1 wt% 2"U or
< 15 g "U 2
C-745 J Storage Yard Crushed Stone
<1 wt% 2"U or 2
< 15 g "U l
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L GDP 99-0043 Paducah Response to RAI Page 3 of 7-L Q2 (NRC 12/4/98 Letter) -
For the buildings / areas whichyou are requesting CAAS exemption, please indicate which ones l
are directly connected to equipment andprocesses that may contain greater than a safe mass
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l ofuranium.; Describe the controls that are relied upon to ensure that such quantities ofuranium are not transferable to the unmonitored areas during all normal and credible abnormalplant j
conditions. For those buildings / areas requiring CAAS exemption that are not connected to areas processing these quantitles or that have 'heen playsically disconnectedfrom ureas processing these, please describe the controls that are relied upon to ensure connections are not i
. erroneously established j
l Response 2 (Part A) l i
The following table presents a list of buildings / areas which are directly connected to equipment and processes that may contain greater than a safe mass of uranium for which an exclusion to the CAAS requirement is requested. A description of the i
controls that are relied upon to ensure that greater than a safe mass of uranium is not transferable to the unmonitored areas during all normal and credible abnormal plant conditions for each of the buildings / areas is also provided.
i Facility Control (s) i C-310-410 Tie Lines F
C-315 Surge and Waste Building B, C, & D C-315-331 Tie Line D
C-350 Drying Agent Storage Building E
C-410-D Fluorine Storage Building E
C-601 Nitrogen Generator Building Addition A
C-603-E Nitrogen Storage Tank (East)
A C-603-F Nitrogen Storage Tank (Center)
A C-603-G Nitrogen Storage Tank (West)
A C-60 i Utilities Maintenance Building A
l C-607 Emergency Air Compressor Building A
C-620 Air Compressor Room A
C-331 Process Building B
C-333 Process Building B
l' C-335 Process Building B
C-712 Acid Neutralization Pit See Item 4 in response to Question I
GDP 99-0043 Paducah Response to RAI Page 4 of 7 Controls:
A. Pressure differentials between the building air or nitrogen pressures and the operating cascade make back flow of UF into the air or nitrogen systems very unlikely. The plant air pressure is 6
approximately 90 psig and nitrogen presrure is approximately 30 psig. This pressure is regulated down to no less than 5 psig in C-331, C-333, C-335, and C-337 for use. Plant air is used for purging process equipment, and nitrogen is used for purging instrument manifolds. Both nitrogen and plant air are also used in the process seal system. Each cell and major piece of auxiliary equipment has a purge valve that is normally maintained in the closed position. If a purge valve were inadvertently opened on operating equipment, the impact would be immediately obvious due to the substantial increase oflight gasses in the cascade which would result. Therefore, there is very little possibility that one of these valves would be left open to allow back diffusion of UF into the purge air or nitrogen systems. In the unlikely event that this 6
would occur, the large pressure difference between the purge and plant air or nitrogen systems would prevent the UF from back difTusing any further. In addition, a low air pressure alarm is 6
received at 80 psig and shutdown of equipment is required by Procedure CP4-CO-ON3003,
" Plant Air Failure," if the plant air pressure drops below 40 psig. Shut down of plant equipment would reduce UF to subatmospheric, eliminating the possibility of any UF back flowing into 6
6 the air or nitrogen systems Each building has an automatic air / nitrogen crossover set at approximately 2-3 psig. Should nitrogen be lost, plant air would supply the nitrogen loads.
B. The only cell floor areas which contain operating UF process equipment without CAAS 6
coverage are C-333 units 1,2,3, and 4. Although the cell equipment is maintained below 1.0 wt% 235U in the entire building, auxiliary equipment in C-333 (Purge & Evacuation (P&E) pumps, surge drums, and Wet Air pumps) is used to service equipment in C-331 which has the potential to be greater than 1.0 wt% 235U. While the auxiliary equipment mentioned is under 23 CAAS coverage, the potential exists to introduce material above 1.0 wt% 5U into areas of the building without CAAS coverage through incorrect valving operations on the P&E panel. The only area of concem in this case are the Evacuation and Evacuation Return headers in C-333 units 1,2,3, and 4. To reduce this risk, valve lineup sheets are currently required for valving operations on the P&E panels. To ensure equipment status and control are maintained, the requirement for valve lineups, or equivalent administrative controls, will remain in place.
Introduction of materials above 1.0 wt% 235U into the operating cascade is oflow consequence.
The difference between mass flow rates of the operating cascade versus the flow rate of the 235 material being introduced would immediately dilute the arsay to below 1.0 wt%
U. Instead a slow rise in the cascade assay would result which would be detected by online assay monitoring or the periodic assay samples which are pulled in accordance with procedure CP4-CO-CN1058,
" Administrative Control of Cascade Assay."
There are also ground floor areas in C-331, C-333, and C-335 which do not have CAAS coverage. Some of these areas contain cell instrument panels, which are tied to the UF system 6
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ODP 99-0043 Paducah Response to RAI Page 5 of 7 of their associated cell. UF over 1.0 wt% 5U could only be introduced to these panels if the 23 6
assay of the associated cell rose to over 1.0 wt% 235U. As explained above, there is a very low probability of cells in these areas rising to over 1.0 wt% 235U.
C. The valves controlling the eight inch Evacuation header piping in the C-331 to C-315 tie line, and in the C-315 building, are controlled by procedure CP4-CO-CN1028a. This procedure provides instructions for valve operations and leak rating tasks designed to prevent misvalving, mixing of assays, and the admission of excessive amounts oflight gas contaminates (lights) into the cascade. Evacuation header isolation valves in C-331 that isolate the C-331 to C-315 tie line have been closed and tagged "Do not open without Cascade Coordinator's approval."
D. The process "B" stream from C-331 to C-315 tie line, and within the C-315 building, is controlled to less than 1.0 wt% 235 U by cascade gradient and by procedure CP4-CO-CN1028a.
The C-331 bottom assay machine monitors the assay of uranium at the bottom of C-331. Tails 235 assay is low (typically s 0.3 wt% 0) thus it would take a significant amount of time and higher 235 assay material to raise C-315's assay up to 1.0 wt%
U. A rough order magnitude estimation is that it would take hours for the assay to approach 1.0 wt% 235U in C-315. This is strongly dependent on the initial plant conditions. Based on the responsiveness of the C-331 bottom assay machine and reporting results hourly to the Cascade Coordinator, it is reasonable to assume 1
that operator response and action to changes in assay machine readings will occur significantly i
prior to assay changes adversely impacting C-315.
E. These buildings are connected to the cascade piping. The mechanism which ensures such quantities of uranium are not transferred to the unmonitored areas is a pressure differential between the fluorine header and the cascade piping. The fluorine header maintains a pressure of 5 psig and the cascade piping at the point of connection is always below atmosphere. Even in the limiting case of that portion of the cascade approaching atmospheric, (i.e., shutdown),
there still would be no motive force to drive uranium into the fluorine piping. Therefore, the flow is always towards, vice away from, the cascade. If the fluorine piping were to be severed, the flow would still be toward the cascade because the cascade, at the points of connection, is subatmospheric.
F. These tie lines have been cut and capped as defined previously. This tie line previously enclosed a fluorine header from C-410. If the lines were to be severed, the flow would be toward the cascade because, as discussed above, the cascade is subatmospheric at the points of connection.
Response 2 (Part B) l The Nuclear Criticality Safety (NCS) program requires each functional manager to ensure that operations in their area that involve, or could potentially involve fissile material, are identified and evaluated for nuclear criticality safety before initiation of the operation. These operations are covered by an NCSA. The NCS program procedure notes that this includes processes that may
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GDP 99-0043 i
Paducah Response to RAI Page 6 of 7 inadvertently involve fissile material due to a process upset condition. In addition, the modification design coatrol process requires a modification team for all modifications to Q, AQ and AQ-NCS structures, systems and components (SSCs). NCS is represented on every modification team until j
it is determined NCS is not affected by the modification. NCS participation is mandatory for all l
modifications dealing with fissile material operations. All modifications to Q, AQ and AQ-NCS
. SSCs are also reviewed by Nuclear Safety Analysis against the SAR accident analysis and approved Nuclear Criticality Safety Evaluations / Approvals. Finally, these modifications must be reviewed and approved by the Plant Operations Review Committee before implementation.
Q3 (NRC Letter 12/4/98)
Please describe the measures (e.g., postings, training, controlled access, etc.) That will be used to control exempted buildings / areas used to store non-fissile material /equipmentfrom containing quantities offissile material such that a critical excursion is not possible.
Responsc 3 As required by the Safety Analysis Report (SAR) all fissile material operations shall be evaluated by Nuclear Criticality Safety (NCS) to determine if there is a need for Criticality Accident Alarm System (CAAS) coverage. This commitment is implemented by plant procedures and communicated to the employees through training. Personnel allowed into the work areas of the Paducah Gaseous Diffusion Plant (PGDP) go through a General Employee Training (GET) class. GET training and/or testing is required every two years. This training includes general NCS training which informs the personnel of criticality concerns and the potential for criticality accidents. This training also discusses the purpose of and the correct response to the CAAS krm.
In addition this training explains the differences between c sntamination areas and non-contamination areas. The contamination limit is more restrictive than the fissile material limits of I wt. % or greater of 2"U, and 15 grams or more of 2"U. Employees / personnel are instructed that radioactive material is not to be removed from a contamination area. The training emphasizes the NCS postings (which specify the NCSA controls), Fissile Control Area markings and that only specially trained personnel are allowed to move or handle fissile material.
Personnel who are allowed to handle or direct the activities of workers who handle fissile /potentially fissile material are also required to complete much more detailed NCS training. This training discusses the definition of fissile material, explains the parameters which affect criticality safety, and explains the application of these principles.
In addition, this training covers personnel responsibilities related to performing all fissile material operations in accordance with approved NCSAs and procedures.
Procedures, and supervision provide additional controls to prevent individuals from moving fissik material into areas out side of CAAS coverage. Plant procedures require that all oper ons which
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Paducah Response to RAI Page 7 of 7 could potentially involve fissile material be performed in accordance with NCSAs and approved l
procedures. NCS is required to review procedures for operations which involve or potentially mvolve fissile material and to determine the need for CAAS coverage.
l To ensure compliance with the NCS program requirements specified in the training and procedures, L
walk-throughs and surveillances are performed by NCS, plant management, and the Safety, Safeguards, and Quality Organization. These walk-throughs and surveillances ce performed in part to ensure that operations involving uranium enriched to I wt. % or greater and 15 grams or more of 2"U have been reviewed and approved by NCS, as well as to verify conditions have not been altered to adversely affect NCS. This review and approval process includes compliance with CAAS requirements.
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Portsmouth Updated References to May 22,1996 submittal m
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1 r ADDENDUM TO POEF LMUS-10,' Criticality' Accident Alarm System Coverage and Exclusions",
Revision 3, December,1998, by J. A. Rapp Jr.
The following addendum to Section 2 of the subject report includes the changes from the latest Lease Change between the DOE and the USEC. None of the facilities added to the Lease require coverage by CAAS. None of the facilities deleted required coverage by CAAS.
FACILITIES ADDED X-106C _
- New Fire Training Building X-230A-41 Ambient Air Monitoring Station A-41 (located offsite at Zahn's Corner)
X 611E Clearwell and Chlorine Building (at X 611 water treatment facility)
X-747 Clean Scrap Yard 1107DV Administrative Vehicle Portal USEC Contractor Trailer Area Approximately 2.8 acres; bounded south by construction road, west by Perimeter Road, north by drainage ditch, and area is directly south of X-6614E FACILITIES DELETED X-100L Environmental ControlTrailer X-106B -
Old Fire Training Building X-630-3.
- Acid Handling Station FACILITY NAME/ FUNCTION CHANGE X-3000 Changed from " Electronic Maintenance Building" to " Environmental Compliance Building" Note: A few editorial changes were made in the updated Lease Agreement to building names or identifying numbers; however, none were substantive with respect to the report evaluation or conclusions