ML20211H125
| ML20211H125 | |
| Person / Time | |
|---|---|
| Site: | Paducah Gaseous Diffusion Plant |
| Issue date: | 09/19/1997 |
| From: | John Miller UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | Pierson R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| GDP-97-0166, GDP-97-166, TAC-L32028, NUDOCS 9710060217 | |
| Download: ML20211H125 (29) | |
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United States y
Enrichment Corporation 2 Democracy Center 9
0903 Rockledge Drive Betheada, MD 20817 Tel: (301)564 3200 rax:(301) 564-3201 J AMEs H. MILLER Dir: (301) 564 3309 VicE PRESIDENT, PRuDUCTioN Fat (301) 571-8279 September 19,1997 Mr. Rooert C. Pierson SERIAL: GDP 97-0166 Chief, Special Projects Branch C. vision of Fuel Cycle Safety and Safeguards, NMSS l
United States Nuclear Regulatory Commission Washington, D.C. 20555-0001 Paducah Gaseous Diffusion Plant Docket No. 70-7001 Response to NRC Request for Additional Information Copeening Seismic Upgrade USQs (TAC NO. L32'o28)
Dear Mr. Pierson:
The purpose of this letter is to respond to the NRC's August 20,1997 letter that requested additional information concerning the unreviewed safety questions associated with the proposed seismic upgrades to Buildings C-331 and C-335. Responses are provided in Enclosure 1.
Ifyou have any questions or comments on USEC's responses, please call me at (301) 564 3301 or Steve Routh at (301) 564-3251. Commitments contained in this submittal are identified in Enclosure 2.
S' g ely, w
es 11. Miller
' ice President, Production
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Enclosures:
1.
Response to NRC Request for Additional Information Concerning Seismic Upgrade USQs (TAC NO. L32028), United States Enrichment Corporation, Paducah Gaseous Diffusion Plant, Docket No. 70-7001.
2.
Commitments Contained in This Submittal.
Nft llllllhlflllll)]l ll ADO OO 01 C
PM Offices in Livormore,Cahfornia Paducah, Kentuck/ Portsmouth, Ohio Washington, DC y
Mr. Robert C. Pierson 5'eptember 19,1997 GDP 97 0166 Page 2 cc:
NRC Region ill Ollice NRC Resident inspector. PGDP NRC Resident inspector. PORTS Mr. Joe W. Parks (DOE) l l
Enclosure I to GDP 97 0166 Page1of22 Response to NRC Request for AdditionalInformation 4
Concerning Seismic Upgrade USQs (TAC NO. IJ2028) i United States Enrichment Corporation
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Paducah Gaseous Diffusion Plant Docket No. 70-7001 1.
Provide a description of the construction sequence to be used to install the structural modifications. Describe how this sequence minimizes the time that the structure is in a degraded state from what currently exists, llow long will the structure be in a degraded condition from what currently exists?
When work was stopped on the seismic ungrade project (see Reference 1), a construction sequence had only been fully developed for installation of the cell floor structural steel. See Table 1. The construction sequence presented in Table 1 is for the building section bounded by Column Lines A,17, Mx, & 9x. The construction sequence is typical for all four of the small footprint building sections bounded by Column Lines A,34, Mx, & l. The construction sequence for the remainder of the large featprint building sections of the cell floor will follow a similar pattern, i.e., demolition of existing bracing in a single " story" of a bay followed by installation of structural elements having larger cross sections in the same bay. Each story of the bay will be worked sequentially until bracing installation is completed. Work typically will begin in a centrally located bay with respect to the building section in plan and proceed outward towards the perimeter of the building section. The construction sequence for the ground floor will be conducted in a similar fashion.
A comparison of the planned demolition /crection schedule presented in Table 1 with the bracing layout shown for the cell floor in Drawing SSE-19484 A03, Resision 3, (provided to the NRC by Reference 2) shows that construction will occur one bay at a time. Demolition will only occur in a single bay between adjacent braced elevations, e.g., from elevation 405'-6" to elevation 417'-11" (braced elevations are generalized spproximations for purposes of this discussian). Erection of replacement steel will immediately follow demolition. The next higher set of bracing in the same bay will then be demolished and replaced. Simultaneou demolition in a bay from cell floor to building roof will not be permitted. The contractor intends to field as many as three crews in each building, with each crew in a separate building bay.
Constructior crews will commence work on the cell floor in the building section bounded by Column Lines A,9, Mx, & l. Constniction will progress clockwise around the building from section to section until the work is complete on the cell.loor. This construction plan ensures that no more than three bays bounded by adjacent oraced elevations are in a degraded configuration at the same time. The construction schedule indicates that, for a bay having 2 braced elevations (e.g.,403' 6" to 434'-21/2",434'-21/2" to 447'-6"), total erection time is estimated to average 14 days. The schedule includes preparatory work such as paint removal and welding enclosures.
<> to GDP 97 0166 Page 2 of 22 TAIILI: 1 Ilracing and Shoring Construction Sequence Stept SmallInternal tinti(C 335 (fnit 2)
Ilounded b Column Lines 9x 17. A Mt 3
Abm e Cell Floor Sten Descrintion lo remove low er brace, column ime 13, D.li li install lower brace, colunm line 13, D ll 2i install lower bt ace, column line J,13 14 and Mx,13 14 30 remove upper brace, col. line 13, D l!
4i install WT to cohunns on lines Mx and 1 Si install upper brace, col. line 13 14 and Mx,13 14 60 remove lower brace, col. hne 14, D l!
6i install lower brace, col. line 14, D-li I
70 remove lower brace, col. line 13, J K 71 installlower brace, col. hne 13, J K 80 remove upper brace, col. line 14. D li 81 install upper brace, col. hne 14, D l!
90 remove upper brace, col hne 13 J K 9i install upper brace, col hne 13, J-K 100 remove lower brace, col. hne 14, J K and A,1314 10i install lower brace, col line 14, J-K and A,13 14 1lo remove middle brace, col line A,13 14 Ili install middle brace, col. line A,13 14 & install WT to columns on A line 120 semove upper brace, col. line A,13 14 12i install upper brace, col. hne A,13 14 13o remose middle brace, col. line 10 D 1!
13i install middle brace, col. line 10, D l!
14o remove upper brace, col. line 14, J K 14i install upper brace, col Ime 14, J K 150 remove middle brace, col. line 10 J K 15i install middle brace, col. line 10, J-K 16o remove top brace, col. line 10, D-l!
16i install top brace, col. line 10, D-l!
17i install top brace, col. line 10,011 180 remove top brace, col line 10, J K 18i install top brace, col. line 10, J K 19o remove middle brace, col. line 17, J K 19i install middle brace, col. line 17, J K 20i install middle lower brace, col. line 10, C F 21i install middle lower brace, col line 17,140 22i install middle upper beace, col. line 10, F.O 23o remove top brace, col. line 17, J K 23i install top brace, col. line 17, J K 240 remove middle brace, col. line 17, D-l!
24i install middle brace, col. line 17, D-li 25i install middle Ivace, col line 17, C-F 26o remove top brace, col hne 17, D li 26i install top brace, col. line 17, D li 27i install top brace, col line 17,011
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Enclosure I to GDP 97-0166 Page 3 of 22 Ilased on discussions with the construction supenisor, the actual time any given bay will exist in the demolished condition is expected to be only a single shift After preparatory work is comple'ed, existing bracing will be removed and the new bracing temporarily installed on the day shift. Final welding and bolt-up will be completed on the night shift. As a result, each bay segment will exist in a degraded condition for approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. As the work progresses, the stmeture will progressively become stifTer. The initial degradation in the global stiffness of the overall structure will be short-lived and localized to a single building section.
(Buildings C 331 & C 335 are composed of 8 structural sections, each section is separated by expansionjoints.)
Drawing SSE 19484 A02, Revision 1, shows the ground floor locations of bays receiving new bracing and bays where bracing is being replaced. Ground floor bracing provides a load path for lateral loading on the structure from the cell floor to ground. The ground floor installation will proceed in the same fashion as for the cell floor but commencement of work on the ground floor will not begin until work on the cell floor is complete. In addition, replacement ofexisting bracing on the ground floor will not commence until installation of new
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ground floor bracing is complete. Bracing installation on the ground floor will not require i
degradation of the pre-construction stiffness of the building sections.
The structure above the cell floor will exist in a configuration somewhst sofler than its pre-construction configuration for a short time (estimated to be less than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for each building section, 8 sections per building).
This estimate assumes that, for cell floor construction,3 of the 9 bays in a building section at the cell floor elevation for which bracing steel is being replaced are demolished consecutively. As construction progresses, the overall stiffness of the building sections will increase and will quickly exceed their pre-construction stiffness. Construction will proceed from the center of the structure towards its perimeter so as not to aggravate torsional effects that may be induced by potential wind activity during construction.
The intent is to follow this construction sequence. This sequence may be modified due to unanticipated field conditions which may delay the demolition or installation at a particular bay. This flexibility will be utilized to maximize the efliciency of the work force while minimizing the overall constmetion duration.
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b Enclosure I to GDP 97-0166 Page 4 of 22 2.
Identify equipment that could be alTected assuming that a load handling accident occurs, including equipment in the ground Hoor that could be damaged assuming that steel being erected on the cell floor penetrates the floor. Provide justification if Door penetration cannot occur. Identify those pieces of equipment that could be damaged concurrently by a singleload handling accident llave the consequences of each scenarlo been addressed in the SAR7 If so, identify the scenarlo in the SAR. If not, provide a detailed discussion of those consequences.
l Identification of Equinment That Could Be Imnacted As shown on the installation drawings provided to the NRC by Reference 2, str ictural steel bracing is planned to be added throughout Buildings C 331 and C-335. Based a the l
extent of the planned modifications, it must be assumed that any of the important to safety (Q and AQ) equipment located on the cell and ground floors could be impacted by a postulated load handling accident. Based on SAR Section 3.15, Q and AQ equipment located in Buildings C 331 and C-335 that could be impacted by a postulated load handling accident includes the follow'mg:
Cell Floor and Ground Floor O Equinment UF6 Release Detection Systems for Equipment Operating above Atmosphere R-ll4 Coolant Over pressure Control System Freezer / Sublimer liigh liigh Weight Trip System Intermediate Gas Removal liigh Temperature Control System Criticality Accident Alarm System Portable Criticality Accident Alarm System -
Cell Floor and Ground Floor AO Equipment Waste Scales located in C 335 Datum Systems for the Enrichment Facilities Surge Drum Pressure / Room Temperature Instrumentation High Pressure Fire Water System Cascade Piping and Equipment Portions of Non-radiological Chemical Systems Distribution Piping Cell Remote Manual Shutdown System Onsite Warning / Evacuation Systems Seismic Instmmentation Mass Spectrometers
f Enclosure I to GDp 97-0166 Page 5 of 22 Potential for Penetration of the CelLElent No analysis has been performed to determine if a postulated drop of the steel to be installed on the cell floor would penetrate the floor.1lowever, based on the size of the new bracing, the design of the cell floor, and the numerous potential drop orientations, it is unlikely that such an analysis would reasonably conclude that no penetration of the cell floor would occur under r.ny circumstances. Consequently, as discussed in the first paragraph of this response,it must be assumed that a postulated load drop above the cell floor will penetrate the floor and potentially impact Q and AQ equipment located on the ground floor.
C.pnsequences of Postulated I,oad llandling Accident No detailed analyses have been performed to estimate the specific radiological consequences of a postulated load handling accident during the seismic upgrade project.
l llowever, as described in Enclosure 1 of Reference 3, the key characteristics of a postulated i
load handlit g accident (i.e., nize of dropped load, plant operating condition, response time) l have been compared against existing accident analyses in the Safety Analysis Report (SAR) and Compliance Plan issue 36 (Reference 4). The conclusion of this comparison is that the radiological consequences of a postulated load handling accident are bounded by the accidents currently evaluated in the SAR and the Justification for Continued Operetion (JCO) for Compliance Plan issue 36:
SAR Ecction 4.3.2.1.1 analyzes a postulated drop of a 33 ton '00U converter. In that analysis, a dropped converter is assumed to cause a complete rupture of the "II" bypass line on a cell operating at pressures up to 22 psia Administrative controls require an operator to be on the cell floor and in contact with the Area Control Room (ACR) thr ough radio or telephone when equipment is being moved over cells operating above atmospheric pressure. The analysis assumes that in the event of a drop, the operator on the cell floor would notify the ACR operator and motor shutdown would occur within 30 seconds. The cell would quickly drop to below atmospheric pressure, limiting the amount of UF, released to no more than 4000 lbs. Closure of the MOVs terminating the release is assumed to occur in 2.5 to 3 minutes.
The radiological consequences of a potulated load drop during the seismic upgrade project are less than evaluated in SAR Section 4.3.2.1.1 for the following reasons:
The weight ofeach liflis significantly less (5 tons versus 33 tons). A postulated load handling accident would produce less damage to cascade equipment (e.g., size of hole, single versus multiple holes, etc.) than assumed in the SAR accident analysis for the drop of a converter.
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Enclosure i to GDP 97-0166 Page 6 of 22 During the seismic upgrade project, a PGDP operations representative will witness each lin and will maintain voice contact with the facility ACR throughout the lifl and ensure that the ACR is notified as quickly as possible should a load handling accident occur. Thus, consistent with the assumptions in SAR Section 4.3.2.1.1, termination of any release would also be expected to occur within 3.5 minutes (0.5 minutes to notify the ACR plus a max mum of 3 minutes for MOV closure).
The current restrictions on subatmospheric operation in Buildings C-331 and C-335 will f" reduce any potential releases below the 4000 lbs of UF reported in SAR 6
Sectiv.. -,.3.2.1.1.
The JCO for Compliance Plan issue 36 evaluates four postulated seismic failure cases that predict uraniurn uptake and liF exposure to individuals (see Table 1 of Compliance Plan issue 36 and Reference 5). The bounding case assumes a complete building collapse and the release of the entire contents of the cascade system. An actual release of 41,670 lbs of UF per building or 83,340 lbs total for both buildings is predicted. (See the response 6
to Question 3 for a further discussion of the DOE bounding case analysis provided in the JCO for Compliance Plan Issue 36 ) The calculated consequences of this bounding case exceed the less than 4000 lbs of UF. that may be predicted to result due to a postulated load handling accident.
A description of the consequences of a postulated load handling accident is not planned to be added to the SAR because load handling during the seismic modifications is a temporary (and not permanent) change to plant operations described in the SAR.
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Enclosure I to GDP 97-0166 Page_7 of 22 3.
The amendment request uses the bounding case of a completely collapsed building to justify all three USQs. The bounding case is described in Compilance Plan 36 as a complete building collapse and the release of the entire contents of the cascade system into the collapsed structure. Compliance Plan Issue 36 defines a collapsed building as the building fell over onto its side Describe how tots '
llapse (i.e., building falling over onto its side) envelopes the three USQ situations in the nendment request given that the three
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potential USQ failures and associated release mechanisms differ substantially from total collapse as defined. Does the bounding case of total collapse, as defined in the Compliance Plan, and release of the cascade system contents into the collapsed structure assume that i
the collapsed structure prevents the conttnis, or a portion of the contents, from escaping?
The bounding case analysis prepared by DOE and presented in the JCO for Compliance
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t Plan Isme 36 considered the plant to be operatir g at 2200 MW (assumed to be the maximum
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power level for subatmospheric operation). Under these conditions, each '00' building would contain about 61,750 lbs of UF.. The release scenario assames that the buildings fall over on l
their sides and are compressed to a height of 8 feet. This corresponds to the diameter of the converters which are assumed to prevent the buildings from being completely flattened It was further assumed that UF in the piping and equipment is released over a 5-minute period into 6
the 8-foot Ifgh collapsed structures except for that retained in the ponion of the converters below the inlet and outlet pipine This results in an actual release of about 41,670 lbs per building (or 83,340 lbs total for both buildings).- The UF. is assumed to mix with air hasing suflicient moisture to react instantaneously and completely in the building and to mix with hot R-114 released from 4 coolant systems. The release of reaction prod icts to the at nosphere is modeled as a puff release that considers thermodynanti effeus. No deposition of reaction i
products _was allowed inside the buildiag or from the plume, resulting in conservative results.
(Refer to Reference 5 for the DOE analysis performed in support of the JCO for Compliance Plan Issue 36.)
The three USQs associated with the modification of Buildings C-331 and C-335 are discussed below:
USQ 1: The increased stiffness of the buildings following completion of the modifications may increase the number and the probability of_ seismically-induced equipment failures inside :he buildings.
Table 1 of Reference 6 and Table 1.1 of Referuce 7 identify equipment in Buildings -
C-331 and C-335 pre'.icted to fail as a result of a revised Evaluation Basis-Earthquake of 0.15g once the structural modifications are completed. A release of 1,920 lbs of UF is predicted to result (Reference ti) which is less than the total of 83,340 lbs UF, predicted to result from building co!bpse.
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' to GDP 97-0166 Page 8 of 22 USQ 2: The process ofinstalling new structural steel may temporarily make the building and contained equipment more susceptible to seismically-induced failure as the existing structural frames are altered and/or replaced.
As a worst case, any instability caused by the construction would result in building collapse equivalent to the scenario evaluated in the JCO for Compliance Plan issue 36.
USQ 3: The process of installing the new structural steel may temporarily increase the probability of equipment failures due to postulated load handling accidents during construction.
As described in the response to Question 2, the radiological consequences of a postulated load handling accident are less than currently evaluated in SAR Section 4.3.2.1.1 and the JCO for Compliance Plan Issue 36.
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ODP 97-0166 Page 9 of 72 4.
You have stated that an operations representative will be witnessing all lifts and will maintain voice contact with the Area Control Room, Approximately how long will it take to isolate a pipe t' tak or a piece of equipment should a load handling accident occur and what is the ma) < mum amount of material that would escape during this time? Is this amount bounted by SAR accident analyses? Describe any other responsibilities of operations pc.sonnel in assuring that the construction is performed safely.
As discussed in the response to Question 2, the analysis described in SAR Section 4.3.2.1.1 bounds the radiological consequences of a postulated load handling accident.
Termination of any release would be expected to occur within 3.5 minutes (0.5 hutes to notify the ACR plus a maximum of 3 minutes for MOV closure). The maximu.a amount l
released would be less than 4000 lbs of UF..
l The responsiblities of PGDP operations personnel in ensuring that construction activities associated with the seismic upgrade project are performed safely include the following:
I Work associated with the seismic upgrades will be performed in accordance with the 4
wek control process. Work plans will be reviewed and approved by contractor, PGDP construction engineering, and PGDP operations personnel.
l Before the initiation of demolition / installation work, the method and ex'ent of pmtection required in the work space will be determined and agreed to by the contractor, tne PGDP construction engineer, and a PGDP operations representative.
Lift plans will be developed for each liR and will be reviewed m h1 approved by contractor, PGDP construction enginee:ing, and PGDP operations personnel.
A PGDP operations representative will witness each lin and will maintain voice contact.
with the facility ACR throughout the lin to ens ire that the ACR is notified as quickly as possible should a load hand!ing accident occur.
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E to GDP 97-0166 -
Page 10 of 22 5.
Describe the experience level of the onsite individual (s) who will directly oversee the construction and be responsible for construction safety. Will all rigging be inspected by an experienced rigging person prior to each lift? Describe the experience of the rigging inspector.
The steelinstallation will be performed by J.S. Alberici, an outside construction company.
J.S. Alberici was founded in 1918 and is the 38th largest contractor in the United States, with one of the largest and most modern fabrication shops in the Midwest. J. S. Alberici has been placed on the USEC/LMUS Approved Suppliers List and has demonstrated the capability to perform work in accordance with the USEC Quality Assurance Program Description.
J. S. Alberici will assign competent construction superintendents to the project who will directly oversee construction activities. The responsibilities of the construction superintendent include construction safety and inspection. The minimum qualifications for construction superintendents includes a high school diploma or general education degree (GED), or 10 to l
15 years related experience and/or training; or an equivalent combination of education and exper' nce.
Ropes, chains, slings and other rigging equipment will be inspected prior to each lift t
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, to GDP 97-0166 Page11of22 6.
Describe why the lins will be hand rigged and not involve use of the crane. Will you employ redundant rigging for critical lifts?
Bracing is not being installed in areas of the building accessible by existing overhead i
- crancs. Erection lins will be hand rigged because of the tight quarters in which the bracing.
steel must be installed.- For the same reason, redundant rigging is not practical. Erection lins for this project will be treated as non ordinary lins. As such, these lins require a rigging plan l
l specific to each set oflins required for installation of steelin a given bay, Lin-specific rigging plans will be developed for each lin and will be reviewed and approved by contractor, PGDP construction engineering, and PGDP operations personnel.
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GDP 97-0166 Page 12 of 22 7.
Will the construction be performed by USEC personnel or an outside co-action company? If outside construction company, describe their experience in t..
.srming similar projects. What USEC training will construction personnel receive prior to beginning construction? Ilow will sefety-related equipment and hazardous lifts be identified to construction personnel?
As described in the response to Question 5, the steel installation will be performed by J.S.
Alberici, an outside construction company. Similar projects performed by J. S. Alberici include Construction of New Galvanizing Line for National Steel Corporation, Seismic Upgrading of Brew House for Anheuser-Bush Company, and Steel Removal and Replacement for Elf Autochem. This experience demonstrates the ability of J. S. Alberici to work in an operating environment.
Construction personnel will receive the following USEC/LMUS training as applicable to theirjob activities:
General Employee Training (Initial)
General Topics General Employee Radiological Training Waste Generator General Nuclear Criticality Safety Security Orientation (Initial Security Briefing)
Respirator Training (Specialty Workers)
Fire Watch (Triennial)
Lockout /Tagout Safety & Health Work Permits Rad II(Initial)
Confined Space (Attendant / Entrant)
Confined Spa:e (Supervisors)
The contractor will provide rigging and hoisting training and fall protection training for those employees responsible for work under these programs.
Important to safety equipment and hazardous lifts are identified to the construction personnel though the precautions section of the work plans. The construction personnel are briefed on the work plans prior to work execution.
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. to GDP 97-0166 Page 13 of 22 8.: What is the maximum voltage of electrical lines in the vicinity of the steel installatior.?
Will electrical lines be de-energized during construction near such lines? If not, what g ecautions will be taken to assure that no electrical mishaps occur?
The maximum voltage of electrical lines in the vicinity of steel installation will be a nominal 14000 volts on the ground floor and 4160 volts on the cell floor. The electricallines carrying these voltages will not be de-energized during construction.
Steel installation will be controlled through the work control process and will be
- conducted in accordance with the Project Health and Safety Permit. The Project Health and Safety Permit provides a consistent evaluation of the potential safety and health hazards in planned work and initiates the establishment of appropriate protective measures. Barriers or administrative controls will be provided as specified in the permit to protect electrical lines l
from direct impact during load movement.
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- - to GDP 97-0166 Page 14 of 22-9.-
Describe any precautions or physical protection that will be implemented to protect conduits and electrical cables, piping and equipment from failing to function as concrete is removed and as steel is installed. Include consideration of concrete dust, falling pieces of concrete, and concrete spalling (spalling can occur onto the ground floor from work being performed on the cell floor), as well as steel installation.
Contractor work plans will require that PGDP construction engineering and contractor t
personnel survey each work site for important to safety equipment prior to commencement of work. Equipment important to safety has also been identified in the fiehl by white metal tags.
l-Before the initiation of demolition / installation work, the method and extent of protection l-required in the work space will be determined and agreed to by the contractor, the PGDP I
construction engineer, and a PGDP operations representative. Protection will take the form of a physical barrier or administrative controls.
4 Ihe amount of concrete dust and debris generated by the seismic modificatians is expected to be small. The dust will be controlled by applying a constant water mist to the area in which existing concrete is to be removed. Control of concrete dust generated by sawing the concrete has been successfully controlled by misting at PGDP in the past. Where concrete fragmenta are expected to fall into equipment or work areas, confmement barriers will be erected to catch the debris.
-c Enclosure I to-
- GDP 97-0166 Page 15 of 22
- 10. Describe safety precautions that will be taken with regard to torch cutting and welding operations. What fire protection measures will be in effect during such operations?
Briefly describe plant procedures that govern these operations.
Torch cutting and wdding operations and their associated fire protection measures are contained in plant procedures that deal with control of welding and burning operations and the issuance of hot work permits. Safety precautions and protective measures that will be in effect and enforced will be included in a safety and health work permit and/or a welding / burning / hot work permit that will be issued for each hot work operation. In addition, work areas will be maintained free of combustible materials, opening in walls and floors will be covered or closed to reduce the dispersion of sparks, combustibles in adjacent areas will be removed or protected from the impact of sparks and heat, the nearest firefighting equipment and phone / fire alarm box will be identified, and fire watches will be provided. In addition, non-combustible housings / shielding will be utilized as necessary at each work location to protect adjacent equipment from sparks, hot slag, direct flame or arc contact, and elevated temperatures.
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. Enclosure 1 to GDP 97-0166 Page 16 of 22
- 11. Describe safety precautions that will be taken with respect to personnel and equipment in the drum storage rooms.
In addition to'the safety precautions described in the responses to Questions 4 and 10, the work environment in the drum rooms will be evaluated for heat load, external and airborne exposure to radioactive materials, and radioactive materials sarface contamination. Appropriate protective measures will be implemented utilizing radiation work and safety and health work permits and the recommendations of the contractor's industrial hygienist.
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Enclosure I to GDP 97-0166 Page 17 of 22
- 12. Ilow will it be assured that the steelis installea in the correct location since it may be possible for the steel to be installed in multiple focations given the similarity of the
-installations? This is especially important considering that the ground floor steel is specified to be ASTM A572, Grade 50 and cell floor steelis specified to be ASTM A36.
Will ground floor steel be segregated from cell floor steel? What quality assurance and quality control (QA/QC) measures will be applied to this project?
The steel is marked at the fabrication facility with a unique identifying code. This code allows the piece to be traced back to the mill heat from which it was rolled, post mill certification specimen testing results, fabrication marks, and erection sequence marks. The unique identification markings are applied during fabrication using a set of punches that indelibly mark the piece. Markings are verified when received at PGDP. Once identified, the steel is stored in accordance with these markings on a marked and coded yard laydown plan.
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Prior to installation, the contractor supervisor verifies the pieces to be installed in a given location are marked and in accordance with the erection drawings. The installation is reviewed by PGDP constmetion engineering for adherance to constmetion drawings.
I Segregation will be enforced in yard storage facilities and during construction.
Segregation will be facihtated by the unique markings on each piece of steel to be installed as well as the construction sequence. A storage yard map indicating storage sites for the pieces I
I as they are stored will be maintained by the contractor.
All_ work performed on the seismic upgrade project will be in accordance with the requirements of the USEC Quality Assurance Program Description. Specific QA/QC measures are identified in project documents that are available at the site for NRC review.
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Enck :ure I to GDP 97-0166 Page 18 of 22
- 13. Confirm that all steel connections are designed as bearing connections, and that design torque will be obtained using the " turn-of-the-nut" method.
Buildings C-311 and C-335 are of AISC Type II braced frame construction. Existing connections in the structures are predominately riveted. Bolted connections for the seismic upgrade project are designed as shear / bearing type connections for use in diagonal cross-bracing. Since the bracing is being installed in a building having a crane with a iill capacity l
in excess of 5 tons, the 7/8"-diameter A 325 bolts will be installed tising calibrated wrenches to a minimum tension of 39 kips in accordance with the recommendations of Reference 8.
" Turn-of-the-nut" tightening will not be used, l
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. - - to GDP 97-0166 Page 19 of 22
- 14. Ilow will-interferences encountered during steel installation be clearcd? Will the interferences he " field relocated" or will engineering assistance always be required? Ilow will you assure that these relocations are reficcted in the drawings?
Numerous interferences were identified during the development of the conceptual and detailed designs of the structural steel installation. As interferences were identified, relocation design drawings vtere developed. The physical relocation ofinterferences is performed by PGDP maintenance personnel.
PGDP design engineering provides final approval of interference relocations.
If the steel installation is found to interfere with existing systems, structures, or components, the steel installation will be stopped and PGDP engineering assistance will be i
requested. Modifications to the plant will be documented in accordance with the existing i
design process.
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- . to GDP 97-0166 Page 20 of 22
- 15. Will masonry installation be reinforced or unreinforced? If unreinforced, what safety related equipment is located in the vicinity of these walls and will collapse of these masonry walls during a seismic event affect safety-related equipment?
To facilitate the installation of bracing steel, portions of the unreinforced masonry walls in the Change House and the Area Control I.com (ACR) will be dmolished and reconstructed.
Reconstruction of the Change House masonry wall involves relocation of an t xisting door in an interior wall of the Change House. No exterior walls of the Change House will be l
affected. The door is being relocated to provide access that would otherwise be blocked by the l
installation of steel cross bracing members. The doonvay relocation is on an interior wall of the Wash House. There are no important to safety SSCs located inside the Wash House.
The masonry walls in the ACR that enclose the kitchen and toilet facil: ties will be demolished and relocated slightly to allow installation of steel cross bracing. Both wall segments currently exist in Buildings C-331 and C-335 and are of unreinforced masonry construction.
The replacement wall segments will also be of unreinforced masonry construction. A seismically-induced collapse of these masonry wallu could impact the Unit 2 control cabinets lecated in the ACR. Loss of the control cabinets would impair operation;
~ however, shutdown of the unit could be accomplished from the C-300 control room if necessary.
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- 16. The time required to complete construction is a factor to be considered in one of the USQs. The total time that the structure is more susceptible to seismically induced failure is dirtetly related to risk. The previously approved schedule required 91/2 months from the start of steelinstallation to completion of the modification. In your July submittal, you requested to extend the completion time to 18 months after release of the project.
- Describe the reasons for requesting an additional 8 % months. In light of the above, further justification is necessary to extend the completion time as requested.
The 9% months assumed a two shin operation with two sets of construction, inspection, operations, s.nd construction support (health physics, construction engineering, security, escorts) personnel. A ramp-up to 160 workers was required at a training rate of 25 every other week. The 9%-month schedule also assumed no float. If efliciency started to slip, a third shin would be necessary.
The requested extension of the con;truction schedule to 18 months is based on the following:
Mobilization: 4 months Final approval and issue of design accu.nents " Certified for Construction"
(
based on resolution of USQs.
i Development and approval of contractor work packages.
Contractor hiring and training personnel.
Construction: 12 months i
Primarily single shin work with second shin devoted to work activities not related to lining. Examples include welding and inspection.
Contingency: 2 months Heat stress rdated efliciencies Evacuation of non-essential personnel Heal h Physics considerations t
The 18-month schedule is preferred for control of the work. Also, the total number of personnel working inside the process buildings near operating equipment will be less. By reducing the total number of personnel on shift, the overall construction safety of the project will be increased.
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. to GDP 97-0166 Page 22 of 22 Errerences
- 1.. Letter from James H. Miller, USEC, to Dr. Carl J. Paperiello, NRC, "Paducah Gaseous Diffusion Plant (PGDP), Docket No. 70-7001, Seismic Risks and Modifications at PGDP, Compliance Plan Issue 36," GDP 97-0101, dated June 30,- 1997.
2.'
Letter from Steven A~. Toelle, USEC, to Mr. Robert C. Pierson, NRC, "Paducah Gaseous DiEsion Plant (PGDP), Docket N o. 70-7001, Final Design Information for Planned Stmetural Moditintions to Buildings C-331 and C-335, Compliance Plan Issue 36," GDP 97-0138, dated July 31,1997.
3.
Letter from James H. Miller, USEC, to Dr. Carl J. Paperiello, NRC, "Paducah Gaseous Diffusion Plant (PGDP), Docket No. 70-7001, Certificate Amendment Request - Buildings C-331 and C-335 Seismic Upgrades," GDP 97-0136, dated July 31,1997.
l 4.
" Plan for Achieving Compliance with NRC Regulations at the Paducah Gaseous Diffusion Plant," DOE /ORO-2026, Issue 36 - Seismic Capability of Buildings C-331 and C-335.
5.
Letter from Joe W. Parks, DOE, to Ms. Elizabeth Q. Ten Eyck, NRC, " Revised Justification for Continued Operation for the Paducah Gaseous Diffusion Plant During Seismic Modifications," dated July 26,1996
' 6.
DAC-M0848401-SAR-62, Addendum 1," Revised Source Terms for Paducah Evaluation Basis Seismic Event," Lockheed Martin Energy Systems, Inc., June 20,1997.
7.
V./GDP/SAR-127/R2, " Cumulative Seismic Effects for Paducah Gaseous Diffusion Plant "00" Buildings C-331 and C-335 Piping and Equipment," Lockheed Martin Energy Systems, Inc.,
March 1997.
8.
Specification for Structural Joints Using ASTM A325 or A490 Bolts, November 13, 1985,
. American Institute of Steel Constructicu Chicago, IL.
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.. to GDP 97-0166 Page1 of5 COMMITMENTS CONTAINED IN Tills SUBMITTAL 1.
The construction sequence presented in Letter GDP 97-0166 (Enclosure 1, Table 1) is for the building section bounded by Column Lines A,17, Mx, & 9x. The construction sequence is typical for all four of the small footprint building sections bounded by Column Lines A,34, Mx, & l. The construction sequence for the remainder of the large footprint building sections of the cell floor will follow a similar pattern, i.e., demolition of existing bracing in a single
" story" of a bay followed by installation of structural elements having larger cross sections in the same bay. Each story of the bay will be worked sequentially until bracing installation is completed. Work typically will begin in a centrally located bay with respect to the building section in plan and proceed outward towards the perimeter of the building section. The construction sequence for the ground floor will be conducted in a similar fashion.
A comparison of the planned demoiition/ erection schedule presented in Table I with the bracing layout shown for the cell floor in Drawing S5E-19484-A03, Revisio'13, (provided to the NRC by Reference 2) shows that construction will occur one bay at a time. Demolition will only occur in a single bay between adjacent braced elevations, e.g., from elevation 405'-6" to elevation 417'-11" (braced elevations are generalized approximations for purposes of this disussion). Erection ofreplacement steel willimmediately follow demolition. The next higher set of bracing in the same bay will then be demolished and replaced. Simultaneous demolition in a bay from cell floor to building roof will not be permitted. Construction crews will commence work on the cell floor in the building section bounded by Column Lines A,9, Mx,
& l.
Const>uction will progress clockwise around the building from section to section until the work is complete on the cell floor. The construction plan ensures that no more than three bays bounded by adjacent braced elevations are in a degraded configuration at the same time.
After preparatory work is completed, existing bracing will be removed and the new bracing temporarily installed on the day shift Final welding and bolt-up will be completed on the night shift The ground floor installation will proceed in the same fashion as for the cell floor but commencement of work ou the ground floor will not begin until work on the cell floor is complete. In addition, replacement of existing bracing on the ground floor will not commence until installation of new ground floor bracing is complete.
Construction will proceed from the center of the struc*ure towards its perimeter so as not to aggravate torsional effects that may be induced by potential wind activity during construction.
The intent is to follow this construction sequence. This sequence may be modified due to unanticipated field conditions which mw delay tbc demolition or installation at a particular bay.
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GDP 97-0166 Page 2 of 5 This flexibility will be utilized to maximize the efficiency of the work force while minimizing the overall construction duration.
2.
During the seismic upgrade project, a PGDP operations representative will witness each lin and will maintain voice contact with the facility ACR throughout the lin and ensure that the ACR l
is notified as quickly as possible should a load handling accident occur.
3.
The responsiblities of PGDP operations personnel in ensuiing that construction activities associated with the seismic upgrade project are performed safely include the following:
Work associated with the seismic upgrades will be performed in accordance with the work control process. Work plans will be reviewed and approved by contractor, PGDP construction engineering, and PGDP operations personnel.
Before the initiation of demolition / installation work, the method and extent of protection required in the work space will be determined and agreed to by the contractor, the PGDP construction engineer, and a PGDP operations representative.
Lin plans will be developed for each lid and will be reviewed and approved by contractor, PGDP construction engineering, and PGDP operations personnel.
A PGDP operations representative will witness each lift and will maintain voice contact with the facility ACR throughout the lift to ensure that the ACR is notified as quickly as possible should a load handling accident occur.
4.
Competent construction superintendents will be assigned to the project who will directly oversee construction activnies. The responsibilities of the construction superintendent include construction safety and inspection.
The minimum qualifications for construction superintendents includes a high school diploma or general education degree (GED); or 10 to 15 years related experience and/or training; or equivalent combination and experience.
Ropes, cha'as, slings and other rigging equipment will be inspected prior to each lin.
5.
Erection lids will be hand-rigged because of the tight quarters in which the bracing steel must be installed. Erection lins for this project will be treated as non-ordinary lins. Lin-specific rigging plans will be developed for each lift and will be reviewed and approved by contractor, PGDP construction engineering, and PGDP operations personnel.
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Construction personnel will receive the following USEC/LMUS training as applicable to their job activities:
General Employee Training (Initial)
General Topics General Employee Radiological Training Waste Generator General Nuclear Criticality Safety Security Orientation (Initial Security Briefmg)
Respirator Training (Specialty Workers)
Fire Watch (Triennial)
Lockout /fagout Safety & Healtn Work Permits Rad 11 (Initial)
Confined Space (Attendant / Entrant)
Confmed Space (Supervisors)
The contractor will provide rigging and hoisting training and fall protection training for those employees responsible for work under these programs.
Important to safety equipment and hazardous lifts are identified to the construction personnel though the precautions section of the work plans. The construction personnel are briefed on the work plans prior to work execution.
7.
Steel installation wi!! be controlled through the work control process and will be conducted in accordance with the Project Health and Safety Permit. The Project Health and Safety Permit provides a consistent evaluation of the potential safety and health hazards in planned' work and initiates the establishment of appropriate protective measures. Barriers or administrative controls will be provided as specified in the permit to protect electrical lines from direct impact during load movemer;.
8.
Contractor work plans will require that PGDP construction engineering and contractor personnel survey each work site for important to safety equipment prior to commencement of work. Equipment important to safety has also been identified in the field by white metal tags.
Before the initiation of demolition / inst.dlation work, the method and extent of protection required in the work space will be determined and agreed to by the contractor, the PGDP construction engineer, and a PGDP operations representative. Protection will take the form of a physical barrier or administrative controls.
Concrete dust will be controlled by applying a constant water mist to the area in which existing concrete is to be removed. Where concrete fragments are expected to fall into equipment or work areas, confinement barriers will be erected to catch the debris.
9-e o to GDP 97-0166 Page 4 of 5 9.
Safety precautions and protective mcasures that will be in effect and enforced will be included in a safety and health work permit and/or a welding / burning / hot work permit that will be issued for each hot work operation. In addition, work areas will be maintained free of combustible materials, opening in walls and floors will be covered or closed to reduce the dispersion of sparks, combustibles iu adjacent areas will be removed or protected from the impact of sparks and heat, the nearest firefighting equipment and phone / fire alarm box will be identified, and fire watches will be provided. In addition, non-combustible housings / shielding will be utilized as necessary at each work location to protect adjacent equipment f'sm sparks, hot slag, direct flame or arc contact, and elevated temperatures.
- 10. In addition to the safety precautions described in the responses to Questions 4 and 10 of Enclosure I to Letter GDP 97-0166, the work emironment in the drum rooms will be evaluated
. for heat load, external and airborne exposure to radioactive materials, and radioactive materials surface contamination. Appropriate protective measures will be implemented utilizing radiation work and safety and health work permits and the recommendations of the contractor's industrial hygienist.
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- 11. The steel is marked at the fabrication facility with a unique identifying code. This code allows the piece ;o be traced back to the mill heat from which it was rolled, post mill certification specimen testing results, fabrication marks, and erection sequence marks. The unique identification markings are applied during fabrication using a set of punches that indelibly mark the piece. Markings are verified when received at PGDP. Once identified, the steelis stored in accordance with these markings on a marked and coded yard laydown plan. Prior to installation, the contractor supervisor verifies the pieces to be installed in a given location are marked and in accordance with the erection drawings. The installation is reviewed by PGDP construction engineering for adherance to construction drawings.
Segregation will be enforcer' in yard stoiage facilities and during construction. Segregation will be facilitated by the unique markings on each piece of steel to be installed as well as the construction sequence. A storage yard map indicating storage sites for the pieces as they are stored will be maintained by the contractor.
All work performed on the seismic upgrade project will be in accordance with the requirements of the USEC Quality Assurance Program Derription.
- 12. Bolted connections for the seismic upgrade project are designed as shear / bearing type connections for use in diagonal cross-bracing. Since the bracing is being installed in a building having a crane with a lift capacity in excess of 5 tons, the 7/8"-diameter A-325 bolts will be installed using calibrated wrenches to a minimum tension of 39 kips in accordance with the recommendations of" Specification for Structural Joints Using ASTM A325 or A490 Bolts,"
November 13,1985, American Institute of Steel Construction, Chicago, IL, " Turn-of-the-nut" tightening will not be used.
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- 13. The physical relocation ofinterferences is performed by PGDP maintenance personnel. PGDP design engineering provides final approval ofinterference relocations.
i If the steel installation is found to interfere with existing systems, structures, or components, the steel installation will be stopped and engineering assistance will be requested.
Modifications' to the plant will be documented in accordance with the existing design process.
i 14 To facilitate the installation of bracing steel, portions of the unreinforced masonry walls in the Change House and the Area Control Room (ACR) will be demolished and reconstructed. No exterior walls of the Change House will be affected. The replacement wall segments for the ACR will also be of unreinforced masonrj construction.
- 15. The requested extension of the construction schedule to 18 months is based on the following:
Mobilization: 4 months
_ Final approval and issue of design documents " Certified for Construction" a
based on resolution of USQs.
Development and approval of contractor work packages.
Contractor hiring and training personnel.
Construction: - 12 months Primarily single shift work with second shift devoted to work activities not related to lifting. Examples include welding and inspection.
Contingency: 2 months -
Heat stress related efliciencies Evacuation of non-essential personnel Health Physics considerations i
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