ML20237E971
| ML20237E971 | |
| Person / Time | |
|---|---|
| Site: | Paducah Gaseous Diffusion Plant |
| Issue date: | 08/21/1998 |
| From: | Toelle S UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | Pierson R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| GDP-98-0184, GDP-98-184, NUDOCS 9809010347 | |
| Download: ML20237E971 (12) | |
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. A Global Energy Company August 21,1998 GDP 98-0184 Mr. Robert C. Pierson Chief, Special Projects Branch Division of Fuel Cycle Safety and Safeguards, NMSS U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Paducah Gaseous Diffusion Plant (PGDP)
Docket No. 70-7001 Response to Request for AdditionalInformation -Compliance Plan Issue 3, Action 9,
- ASME Code Interpretation and Assessment Results,(TAC NO. L32012)
Dear Mr. Pierson:
The purpose of this letter is to provide a response to the United States Nuclear Regulatory Commission's (NRC) request (TAC No. L32012) for additional information on Compliance Plan Issue 3, Action 9, ASME Code Interpretation and Assessment Results as pertains to the liquid j
transfer operations in C-360. The request for additional information was provided to the United States Enrichment Corporation (USEC)in Reference 1 and identified additional information required i
by NRC to review USEC's submittal (Reference 2) related to Compliance Plan Issue 3, Action 9. to this letter provides PGDP's response to this request for additional information.
Additional investigation into the code requirement shows that the ASME Code Committee has previously issued Code Case Number 2211 (Enclosure 2) which applies to Compliance Plan Issue 3, Action 9. This Code Case specifically addresses the conditions which must be satisfied in order for a pressure vessel to be provided with overpressure protection by system design in lieu of a pressurc relief device. The enclosed response demonstrates PGDP's compliance with this Code Case.
If you have any questions or require additional information, please contact Mark Smith at (301) 564-3244. Commitments contained in this submittal are identified in Enclosure 3.
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Sincerely, A
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a Steven A.Toelle Nuclear Regulatory Assurance & Policy Manager 6903 Rockledge Drive, Bethesda, MD 20817-1818 l
Telenhnne 3m AM.un0 Fax 301-564-3201 http://www.usec.com
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Mr. Robert C. Pierson August 21l1998 GDP 98-0184, Page 2
Enclosures:
1.
Response to Request for Additional Information -Compliance Plan Issue 3,.
Action 9, ASME Code Interpretation and Assessment Results, (TAC NO.
L32012) 2.
ASME Code Case 2211 3.
Commitments Contained in this Submittal ec:
NRC Region III Office NRC Resident Inspector-PGDP NRC Resident inspector - PORTS l
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-Mr. Robert C. Pierson LAujust 21,* 1998 ODP 98-0184, Page 3 References l
d 1.
Letter from Robert C. Pierson (NRC) to Steven A. Toelle (USEC), Paducah Gaseous
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Diffusion Plant and Portsmouth Gaseous Diffusion Plant, Compliance Plan Issue 3, Action 9, ASME Code Interpretation and Assessment Results (TAC No. L32012), dated June 10, i1998.
2.'
' Letter from Steven A. Toelle (USEC).to Robert C. Pierson (NRC), Paducah Gaseous Diffusion Plant /Portsmouth Gaseous Diffusion Plant, Docket No. 70-7001 and 70-7002, Compliance Plan Issue 3, Action 9, ASME Code Interpretation and Assessment Results, (TAC No., L32012), USEC L etter GDP 98-0017, dated February 9,1998.
3.
Letter from Robert L. Woolley (USEC) to Robert C. Pierson (NRC) Paducah Gaseous Diffusion Plant (PGDP), Docket No. 70-7001, Compliance Plan Issue 3, Action 9, ASME Code Interpretation and Assessment Results, USEC Letter GDP 96-0206, dated December
~31,1996.
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Page1of5 Response to Request for Additional Information (TAC No. L32012)
Compliance Plan Issue 3, Action 9, ASME Code Interpretation and Assessment Results USEC has prepared the following response to the NRC's letter dated June 10,1998 (Reference 1),
in which it was noted that 1) the NRC staff is not in position to establish an ASME Code interpretation that positive control of an external heating source would obviate the need for a protective device and that 2) the staff recommends that USEC either comply with the Code, pursue an ASME Code interpretation or seek relief from the protective device provision from NRC.
Further research into the Pressure Vessel Code revealed that, in fact, the ASME Code Committee had previously issued Code Case Number 2211 in reply to an inquiry that applies to Compliance Plan Issue 3, Action 9. ASME Code Case Number 2211, Pressure Vessels With Overpressure Protection by System Design, Approved August 12,1996 (Enclosure 2), provides a response to the following inquiry: "Under what conditions may a pressure vessel be provided with overpressure protection by system design in lieu of a pressure relief device as required by Section VIII, Division 1, para. UG-125(a) and by Section Vill, Division 2, para. AR-100?"
In this Code Case, the ASME Code Committee indicated that a pressure vessel may be provided with overpressure protection by system design in lieu of a pressure relief device as required by ASME Section VIII, Division 1, paragraph UG-125(a) provided that certain conditions are satisfied. These conditions, and the extent to which USEC satisfies these conditions at PGDP, are as follows:
Condition (a)
"The vessel is not exclusively in air, water or steam service."
j USEC Status:
The UF cylinders are not exclusively in air, water or steam service.
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i Condition (b)
"The decision to provide a vessel with overpressure protection by system design is the responsibility of the User. The User shall specify overpressure protection by system design and reference this Code Case in writing in the purchase documents (per Section VIII, Division 1, para. U-2) for a Division j
1 vessel,... The Manufacturer is responsible only for verifying that the User has specified j
overpressure protection by system design, and for listing this Code Case on the Data Report."
USEC Status:
Historically, the Users (both DOE and USEC) have specified overpressure protection by system i
design; UF cylinders have been and are currently procured without pressure relief devices in 6
accordance with ANSI N14.1. Previous and current procurement documentation does not reference i
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l GDP 98-0184 Page 2 of 5 this Code Case number. The procurement documentation will be revised to reference the code case for future purchases at PGDP.
Condition (c):
"The User shall ensure that the M AWP (see Section VIII, Division 1, para. UG-98) of a vessel is greater than the highest pressure which can reasonably be expected to be achieved by the system.
The User shall conduct a detailed analysis which examines all credible scenarios which could result
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in an overpressure condition. The "Causes of Overpressure" described in Section 2 of API Recommended Practice 521 " Guide for Pressure-Relieving and Depressuring System " shall be considered. An organized, systematic approach, using a multi disciplinary team, such as a Hazards and Operability Analysis (HazOp), Failure Modes, Effects, and Criticality Analysis (FMECA), Fault Tree Analysis, Event Tree Analysis,"What-If" Analysis, or other similar methodology shall be used.
In all cases, the User shall determine the potential for overpressure due to all credible operating and upset conditions, including equipment and instrumentation malfunctions.
USEC Status:
Detailed analyses have been performed which examine all credible scenarios that could result in an overpressure condition. The plant SAR and TSRs, which comprise Volumes 1,2 and 4 of the Application, and the SARUP CAR, submitted in accordance with Compliance Plan, Issue 2 and their supporting documentation, provide detailed analyses of the scenarios that could result in an overpressure condition of the UF cylinders. In many cases, the process parameter directly controlled 6
is temperature and/or steam pressure which assures protection against an overpressure condition; administrative controls include those verifying cylinder fill weights. These controls provide overpressure protection for a cylinder being heated in an autoclave.
Accident scenarios for the C-360 Sampling and Transfer Facility are discussed in SAR Section 4.3.5.
Additional explanation of the controls provided to preveut cylinder overpressure are discussed in SAR Section 3.6.7. SAR Section 3.6 describes autoclave design and operation. TSRs describe the use of engineered systems and administrative controls (and their Bases) utilized to maintain cylinder pressures below the MAWP during heating evolutions. TSRs 2.1.4.6,2.1.4.7,2.1.4.8,2.1.4.9 and Design Feature 2.1.5.3 provide a discussion of these administrative controls. SAR Section 3.15 lists the Q systems that provide such overpressure protection to the UF cylinder while being heated in 6
the autoclaves. These engineered controls which limit the UF cylinder pressum during heating were 6
described in our previous submittab. (GDP 96-0206, and GDP 98-0017 February 9,1998; respectively).
The SARUP discussion of potential high cylinder pressure scenarios is found in Sections 4.3.2.2.2, 4.3.2.2.6,4.3.2.2.7,4.3.2.2.14. These scenarios are the result of a systematic approach using multi discipline teams to identify various accidents and initiating events as described in SARUP Sections 4.2 and 4.3 (the methodology application and associated calculations are provided in SARUP support l
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GDP 98-0184 Page 3 of 5 support documentation which is available at the sites for review). These analyses demonstrate that the existing configuration provides an acceptable level of safety.
USEC believes the SAR and SARUP satisfy Condition (c) of the Code Case 2211 for the " detailed analysis which examines all credible scenarios which could result in an overpressure condition".
Condition (d):
"The analysis described in (c) shall be conducted by an engineer (s) experienced in the applicable 4
analysis methodology. Any overpressure concerns which are identified shall be evaluated by an l
engineer (s) experienced in pressure vessel design and analysis. The results of the analysis shall be documented, and signed by the individual in charge of the operation of the vessel. This documentation shall include as a minimum:
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(1)
Detailed Process and Instrument Flow Diagrams (P& ids), showing all pertinent elements of the system associated with the vessel.
i (2)
A description of all credible operating and upset scenarios, including scenarios which result from equipment and instrumentation malfunctions.
(3)
An analysis showing the maximum pressure which can result from each of the scenarios examined in (2) above.
(4)
A detailed description of any instrumentation and control system which is used to limit the system pressure, including the identification of all truly independent redundancies and a reliability evaluation (qualitative or quantitative) of the overall safety system.
The documentation shall be made available to the regulatory and enforcement authorities having jurisdiction at the site whe. e the vessel will be installed. The User of this Code Case is cautioned that prior Jurisdictional acceptance may be required.
i USEC Status:
1 The SAR/SARUP and their support documentation satisfy Condition (d) of Code Case 2211. The SAR and SARUP analyses were performed by engineers and other technical specialists experienced l
in accident analysis methodology and overpressure concerns and were reviewed by engineers and i
other technical specialists experienced in pressure vessel design and analysis. The results of the I
analyses are documented in the SAR/SARUP and their supporting documents as previously I
l discussed. The system design and controls required, based on the analysis, are in place to prevent l
overpressure conditions. This documentation has been inade available, as part of the Certification i
Application, to the regulatory authorities having jurisdiction at the site where the vessels are I
installed.
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l GDP 98-0184 Page 4 of 5 Item (d)(1): PGDP maintains detailed as built process and instrument diagrams for the
. systems providing overpressure protection which show all pertinent elements of the system j
design which provides overpressure protection.
I Item (d)(2): The SAR/SARUP documentation includes a description of credible operating and upset scenarios, including scenarios which result from equipment and instrumentation malfunction.
These are primarily malfunction of steam control valves and/or pressure / temperature sensors '(Q or AQ SSCs) as well as failure to properly implement administrative controls.
1 Item (d)(3): The maximum cylinder pressures and/or temperatures that could develop as a 4
result of the scenarios are discussed in the SAR/SARUP or in the supporting documents as previously discussed. Maximum cylinder pressures can be determined, using these cylinder temperatures, where required, as demonstrated in our previous submittals (GDP 96-0206 and GDP 98-0017).
Item (d)(4): A detailed description of any instrumentation and control system which is used tu limit the system pressure is provided in SAR Chapter 3 (particularly Sections 3.6 and
' 3.15) and in the Boundary Definition manuals for the credited systems. The discussion regarding reliability is contained in the SARUP Section 3.15 and in supporting documents
- (e.g. PSOAS and DACs for the SARUP).
Condition (e):
"This' Case number shall be shown on the Manufacturer's Data Report for pressure vessels that will be provided with overpressure protection by system design, and it shall be noted on the Data Report that prior Jurisdictional acceptance may be required."
' USEC Status:
The Manufacturer's Data Report does not currently show this Code Case number. This needs to be provided both in procurement documentation (as noted earlier) and in the Manufacturer's Data Report. The reason that this information is not currently provided in the procurement documentation associated with the purchase of cylinders is that the procurement documentation referenced ORO-651 or USEC-651 and/or ANSI N14.1, standards which do not require this information directly.
- ORO/USEC-651, Section 8, describes the use of system design and administrative controls for
' overpressure protection during heating of UF cylinders.
l Summary The current SAR and the SARUP (currently under NRC review) provide the analyses required to
! support UF cylinder overpressure protection by system design in lieu of a pressure relief device 6
described in Code Case 2211. As such, we believe that PGDP is in ' substantive compliance with the
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GDP 98-0184 l
Page 5 of 5 I
- ASME Code with respect to overpressure protection during the C-360 transfer operation as described in Code Case 2211.
For the heating of UF cylinders in autoclaves, the plani design and operation (as described in the 6
SAR/SARUP) meet these conditions with one exception (i.e. inclusion of this Case number in procurement documents and having this case number referenced in the Manufacturer Data Report).
As noted above, the Manufacturer's Data Report does not currently show this Code Case number.
USEC commits to meet des Code Case requirement in procurement documentation and to require
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the listing of the Code Case on the Manufacturer Data Report for future cylinder procurement at
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PGDP.
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GDP 98-0184 Three Pages ASME Code Case 2211 I
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Floprcduced from Information H ndling Servicose The 1925 Boil:r and Pressure Vessel Codec 1925 by ASME Tue Aug 04 08:00:081998 i
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2211 Pressure Vessels wit overpassure Protection by Syste= Design Seedon VIE Divij i
2211 2211 Prassers Vessels with Ovegressure Protection by Syste= Design Sectica VIE Divi 1
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' SL'!T. 6 9
ApprovalDate: 212-96 Expiration Date: 3-12-99 SUPP. 6 Irg:iry:
SUPP. 6 -
Under what conditions may a pressure vess:h:$rSYided WiD ove:pnsstre protect!Qn by sysg= design in ligg pressu:e :elief device as requir:d by Sectica VG, Division '., pars. UG 12f(a) and by Secden VII Divisien 2, para.
l AR 100?SUPP. 6 l
Reply:
I stPr. e It is the o#ne of the Committe: dat a pressure vessel =ay be provided with overgessurs pr tecticn by syste=
j design in usu of a pressure relief device as :eg: ired by Sectien VIII, Division 1, para. UG 12f(a) and by Section VE, Division 2, para. Alt.100 underta fonowing conditions:
4 (a)The vessells not exclusively in air, water, or stes= service, (5) The decision to provide a vessel with overpressure protecden by system design is is respensie' ility afcm User.
The UsershnH specify ove.ressurs protec:icnby system design and reference this Code Case in writing in t: purchas documenu (per Section VIII, Division 1, pan. U 2) for a Division 1 vessel, or in te User's Desi;;n Specifca: ion (per -
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Section VIE Diviston 2, para. AG401) for a Div sica 2 vesse!. The Manufacturer is responsible only for vedfying tar the User has specified ovorm-protecnon by system design, and forlisting eis Code Case on tha Data Report I
(e) The User shall ensure ist the MAWP (iee Sec'ian VIII, Division 1, part. UG-93) of the vesselis grn::: than the t
highest prasaure which can ruu unably bc :xpec=d to be achzaved by 2e system. Die User ahall cenduct a dsttiled analysis which exatninas all c: edible scenaries which could result *m sn overpr ssure condition. The "Caus:s of Overpressure' described in Secnon 2 ofAPI.h-ded Prr.ctice 521 *Cside for Pressure 2411evhg and Depr:ssuring Systems" shallbe conndered. An orgenued, systematic approach, using a :nuludiscir.linary tz =, such as a Hazards and Operabuity Analysis (Haz0p), Fa!!ure Modes, Effects, and Crcicality Analysis (F>ECA), Fed Tree Analysis, Eve::t Tree Analyns, 'What-If" Analysis, or other si=ilst methodology sha!! be used. In all cases, to User shan deter =me the potential for overpressure d:e to all credible operstmg and upset conditions, " Mg es:ipment
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and instrumentation mah h
($ The analysis described in (c) shallbe condceted by an engin=:r(s) expedenced in te applicable scalysis methodology. Any overpressure concems whichte identined shall be evaluated by an c::gineer(s) e:ge:inced in pressure vessel deszgn and analysis. The results ofitianalysis shall be documented, and signed by te individna! in charge of the operation of the vessel. This dccu=entstion shallinclude as a -+Wem" (1) Detailed Process and Iestrerect Picw Diagis=s (P& ids), :howing all pertinnut elemen= of te rYnan assedsredwiththe vessel.
(2) A descr*ption of SU credible operating Udupset scenarios, including scenarios which::sult So= eg;ipment and instre-emdon malfunctions.
(3) An analysis showing the ma:cmum presure which enn nsult firom each of the se' ens:fes :xW~d in (2) abcve.
(4) A detsiled description of any inst: ~k" and concel syste=1 which is used to li=it 6e sys*:= pessure, including to identincatica of all truly indep-N whmM.:s and a aliability evaluatica (qualita:ive c:-
t qcan:itative) ofis overall safety syste De doccutemation sh2D be =ade synilshle *.o the regulatcry and nforce=ent zuhozities havingjurisdicion it the
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' Reproduced frorn Inferrnaton Handling sevicese
.c Tho 1995 BoDer and Pressure Vessel CodeC 1995 by ASME Tue Aug 0406:00:081998 h wi6 % essure Protection by System Design SecticuYIII, Divi tite where the venel will be installed. The User of this Code Case is caution =ed that prior Jurisdictional acceptance may be required.
(e) This Caso munbar shan be shown on $a h'Ws Data Report for pressure vesseis that win be provided with overpressure protection by system design, smiit shan be noted on ths Data Report that prior Jurisdictional acceptance may be requirsd.SUPP. 6
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GDP 98-0184 Page1ofI Commitments Contained in this Submittal 1.
The Manufacturer's Data Report does not currently reference Code Case 2211. USEC commits to revise procurement documentation to reference Code Case 2211 and to require that this Code Case be specified in the Manufacturer Data Report for future UF cylinder 6
procurement at PGDP.
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