ML20154L200
| ML20154L200 | |
| Person / Time | |
|---|---|
| Site: | 07007001 |
| Issue date: | 10/09/1998 |
| From: | Paperiello C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | John Miller UNITED STATES ENRICHMENT CORP. (USEC) |
| References | |
| 70-7001-98-06, 70-7001-98-6, EA-98-239, NUDOCS 9810190172 | |
| Download: ML20154L200 (57) | |
Text
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=[ NUCLEAR REGULATOR't COMMISSION I #' WASHW . ,aN. O.c. 20666-0001 8, f l
- October 9, 1998 l-1EA 98-239 !
Mr. J. H. Miller
- Vice President- Production United States Enrichment Corporation Two Democracy Center
- 6903 Rockledge Drive Bethesda,MD 20817
SUBJECT:
. EXERCISE OF ENFORCEMENT DISCRETION AND
SUMMARY
REPORT OF THE JUNE 16,1998, PREDECISIONAL ENFORCEMENT CONFERENCE (NRC INSPECTION REPORT 70-7001/98006 (DNMS) AND LETTER FROM DRJ CARL J. PAPERIELLO TO MR. WILLIAM H. TIMBERS, DATED MAY 28, l
1998.)
Dear Mr. Miller:
l The NRC performed an in-office review of the United States Enrichment Corporation's (USEC) l ll Safety Analysis Report Upgrade Project (SARUP) submittal and conducted a routine resident inspection from March 10 through April 20,1998, at USEC's Paducah Gaseous Diffusion Plant, l
! located in Paducah, Kentucky. The in-office review and onsite inspection identified two apparent i
violations associated with safety analyses and conclusions presented in the SARUP and a third apparent violation associated with a related safety analysis performed to update the current Safety Analysis Report (SAR) for an as-found condition. The SARUP and SAR safety analyses I involved the liquid uranium hexafluoride accumulators used in the product and tails withdrawal processes.' The NRC discussed one of the apparent violations with members of the Paducah 4'l Gaseous Diffusion Plant at the inspection exit meeting, conducted on April 20,1998. The report i,. documenting our inspection was sent to USEC by letter dated May 7,1998. A letter summarizing the remaining two apparent violations was sent to USEC on May 28,1998. An open predecisional enforcement conference was held in the NRC's Washington, D.C. office on June 16,1998, to discuss the apparent violations, the root causes, and USEC corrective actions ph L The predecisional enforcement conference meeting summary is attached.
During the predecisional enforcement conference, USEC denied the two apparent violations associated with the SARUP submittal based upon a belief that it was reasonable and
- appropriate to consider the accumulators empty during the SARUP assessment of the accumulators' response to a seismic event. While the NRC staff recognized that previous l.
seismic design requirements and accident analysis performed during the 1980s appeared to assume the accumulators were empty, such an assumption was inconsistent with current l.
regulatory requirements. The NRC staff also recognized that neither the previous nor the
! current accident analysis design and consequence assumptions were clearly stated so as to casily preclude the submission of incomplete or inaccurate information. Also during the conference, USEC concurred with the NRC's position that the safety evaluation, performed to authorize a modification to the current Safety Analysis Report for the as-found condition of 9810190172 981009 ?
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- 2 increased accumulator capacities, was not well developed and documented. However, USEC disagreed that the as-found condition represented an unreviewed safety question, a condition that would have required a certificate amendment in order to permit continued plant operations.
As indicated in the Confirmatory Order issued to USEC April 22,1998, EA 98-156, the NRC considered continued operation of the accumulators, without certificate controls to ensure compliance with the current accident analysis, a condition inconsistent with the Certificate of Compliance.
Based on the information developed during our review of the SARUP submittal, during the referenced routine resident inspection, and the information USEC provided during the predecisional enforcement conference, the NRC determined that violations of NRC requirements occurred. Specifically, the NRC determined that the SARUP submittal did not consider operations at the maximum capacity of the accumulators, as required by the Compliance Plan and 10 CFR 76.85, " Assessment of Accident," and did not include complete and accurate information as to the potential accident consequences of the failure of full accumulators during a seismic event, as required by 10 CFR 76.9, " Completeness and Accuracy of Information." In addition, the NRC determined that a safety analysis, performed as required by 10 CFR 76.68 for the as-found condition of increased accumulator capacities, failed to identify a condition that would require a certificate amendment to allow continued operations. The NRC determined that the violations were caused, in part, by: 1) a continued application of old design assumptions to current analyses; and,2) a lack of Compliance Plan clarity and USEC understanding as to how the current regulatory requirements were to be applied as a part of SARUP-related activities.
The violations are a significant regulatory concern because they indicate a lack of understanding of the current regulatory requirements, as specified in the Compliance Plan for the SARUP activities, and a lack of rigorous implementation of the regulatory requirements for dispositioning as-found conditions, as specified in the Compliance Plan and Part 76.68. The violations are a significant safety concern because, as a result of the violations, plant operations were incorrectly allowed to continue for approximately one year with unlimited use of the increased accumulator capacities. The occurrence of a seismic event below the design basis, concurrent with the accumulators being filled to capacity, could hsve resulted in significantly increased seismic accident consequences onsite and offsite. Therefore, the violations are classified in the aggregate in accordance with the " General Statement of Policy and Procedure for NRC Enforcement Actions," (Enforcement Policy), NUREG 1600, Rev.1, as a Severity Level 111 problem.
In accordance with the Enforcement Policy, a civil penalty was considered for this Severity Level lli problem. However, I have been authorized, after consultation with the Director, Office of Enforcement and the Deputy Executive Director for Regulatory Effectiveness, to exercise enforcement discretion in accordance with Section Vll.B.6 of the Enforcement Policy and not propose a civil penalty or issue a Notice of Violation in this case. Discretion was warranted because of: 1) the significant correlation between the current issues and previous (old) design practices which appeared to allow the seismic design and accident analysis assumptions used by USEC; 2) USEC's development and prompt implementation of compensatory measures and comprehensive plant design changes to resolve the seismic weaknesses, as identified in the Confirmatory Order issued April 22,1998, EA 98-156; and 3) the corrective actions presented by USEC at the predecisional enforcement conference to improve the rigor and documentation of safety evaluations for as-found conditions. The NRC also determined that the corrective actions, in the Confirmatory Order and those committed to at the predecisional enforcement
. 3 l conference were sufficient to address the violations. However, similar significant violations in
! the future could result in a civil penalty.
The NRC has concluded that the information regarding the reason for the violations; the corrective actions implemented and planned to correct and prevent recurrence of the violations; l and the date when full compliance will be achieved are already adequately addressed on the docket in the Confirmatory Order and the attached Predecisional Enforcement Conference Summary. Therefore, you are not required to respond to this letter unless the description therein does not accurately reflect USEC's corrective actions or position. In that case, or if you choose to provide additional information, you should send the information to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, D.C. 20555 with a copy to the l
Regional Administrator, Region Ill, and a copy to the NRC Resident Inspector at the Paducah Gaseous Diffusion Plant, within 30 days of the date of this letter, in accordance with 10 CFR 2.790 of the NRC's " Rules of Practice," a copy of this letter, its enclosures and your response, if any, will be placed in the NRC Public Document Room.
Sincerely,
[originalsignedby:]
Carl J. Paperiello, Director Office of Nuclear Material Safety and Safeguards Docket 70-7001 l
Certificate GDP-1 '
Enclosure:
Enforcement Conference Meeting Summary l
cc w/encis: H. Pulley, Paducah General Manager L. L. Jackson, Paducah Regulatory Affairs Manager J. M. Brown, Portsmouth General Manager S. A. Toelle, Manager, Nuclear Regulatory Assurance and Policy, USEC Paducah Resident inspector Office Portsmouth Resident inspector Office R. M. DeVault, Regulatory Oversight Manager, DOE J. C. Hodges, Paducah Site Manager, DOE DISTRIBUTION:
Dockets 70-7001,70-7002 [NRc File CenterI ' f Rlli NMss Dir. Off. r/f FCss r/f l
K. O'Brien, Rill P. Hiland, Rill M. Horn Y. Faraz D. Persinko N. Mamish, OE J. Lieberman.OE P. Ting W. schwink D. Hartland, Rlli sPB r/f
- See previous concurrence CP/ PROOFED / SEPTEMBER 17,1998 OFFICE SPB l SPB l lMAB l SPB l SPB l FCSS l OE l NAME CCox/kjc/ij DHoadley SGreene DMartin RPierson ETen Eyck JLieberman DATE 08/11/98 08/13/98 08/18/98 08/18/98 08/18/98 08/19/98 09/03/98 OFFICE OGC Rlli:DNMS Rill:DNMS NMSW)r,/ l l l NAME JGoldberg RCaniano BClayton CPaderidflo DATE 09/09/98 09/09/98 09/09/98 @/(f/98 DOCUMENT NAME: a A98-239.It6 OFFICIAL RECORDS COPY
Certificate Holder United States Enrichment Corporation l Facility: Paducah Gaseous Diffusion Plant Certificate No.: GDP-1 Docket No.: 070-07001 EA Number. EA 98-239 On June 16,1998, representatives of the United States Enrichment Corporation (USEC) met with Nuclear Regulatory Commission (NRC) personnel at NRC Headquarters in Rockville, Maryland, to discuss apparent violations identified in NRC Inspection Report Number 070-07001/98006 (DNMS) and May 28,1998, Mr. Carl J. Paperiello letter to Mr. William H. Timbers. The conference was held at the request of the Office of Nuclear Material Safety and Safeguards.
The certificate holder's presentation was a denial of the apparent violation of Title 10 of the Code of Federal Regulations, Part 76.85 for an inadequate accident analysis, a denial of Title 10 of the Code of Federal Regulations, Part 76.9 (a) for incomplete and inaccurate information, and a challenge to the severity of the apparent violation of Part 76.68 for an inadequate safety evaluation regarding the seismic vulnerability of Building C-315 withdrawal facility and the as-found size error for the withdrawal accumulators. The denial of the first apparent violation (Part 76.85 inadequate accident analysis) was based, in part, on USEC's position that the NRC had previously reviewed and approved the accident assumption that the accumulator would be empty during the seismic event which was later challenged during the Safety Analysis Report Upgrade (SARUP) review process. USEC also denied the apparent violation because they felt that it was process of the submittal, NRC review and approval, and implementation of the SARUP that was intended to meet the requirements of Part 76.85. In addition, USEC denied that the information about the seismic vulnerability submitted with the SARUP was incomplete and inaccurate. The denial was based on their position that informing the NRC that there was an accumulator size error without stating the magnitude of the error was complete and their assessment that the seismic accident consequences were bounded by other accidents was accurate based upon the empty accumulator assumption which was only later challenged. The Part 76.68 inadequate safety analysis apparent violation severity was challenged because USEC believed that the as-found condition did not represent an unreviewed safety question. The certificate holder's view was that the size error required only changes to the SAR Chapter 3 system description to correct the value, that the change did not result in any change to plant operations, and that the accident analysis review did look at all the accidents and based upon the assumptions in those accidents, the size error had no impact on the consequences.
After USEC's presentation, the NRC asked several questions to clarify why USEC felt that the safety evaluation was adequate in view of the unreviewed safety question raised by rejecting the empty accumulator assumption and to ask if there were other examples in the Certification SAR and/or the SARUP where normal operation conditions were used to bound accident.
ENCLOSURE
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1 The attendance list and the certificate holder's presentation are attached to this summary. ;
1 In accordance with 10 CFR 2.790 of the NRC's " Rules of Practice," a copy of this summary and {
l its enclosures will be placed in the NRC Public Document Room.
Attachments: 1. List of attendees 1
- 2. Certificate holder presentation i 1
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l
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3 and the date when full compliance will be achieved are already adequately addressed on the docket in the Confirmatory Order and the attached Predecisional Enforcement Conference l Summary. Therefore, you are not required to respond to this letter unless the description therein i does not accurately reflect USEC's corrective actions or position. In that case, or if you choose i to provide additional information, you should send the information to the U.S. Nuclear Regulatory i Commission, ATTN: Document Control Desk, Washington, D.C. 20555 with a copy to the
! Regional Administrator, Region Ill, and a copy to the NRC Resident Inspector at the Paducah Gaseous Diffusion Plant, within 30 days of the date of this letter.
In accordance w h 10 CFR 2.790 of the NRC's " Rules of Practice," a copy of this letter, its enclosures and yo r response, if any, will be placed in the NRC Public Document Room.
Sincerely, Carl J. Paperiello, Director Office of Nuclear Material Safety and Safeguards Docket 70-7001 Certificate GDP-1
Enclosure:
Enforcement Conference eeting Summary cc w/encis: H. Pulley, Paducah Genera Manager L. L. Jackson, Paducah Reg atory Affairs Manager J. M. Brown, Portsmouth Gen al Manager S. A. Toelle, Manager, Nuclear Regulatory s Assurance and Policy, USEC \
Paducah Resident Inspector Officg Portsmouth Resident inspector Offic.e R. M. DeVault, Regulatory Oversightpanager, DOE J. C. Hodges, Paducah Site Manager, OOE DISTRIBUTION: Ob #f b --
Dockets 70-7001,70-7002 NRC File Center Rlli NMsS Dir. Off. r/f FCss r/f K. O'Brien. Rill P. Hdand, Rlli M. Horn Y. Faraz D. Persinko N. Mamish, OE J. Lieberman oE P. Ting W. schwink D. Hartland, Rlli SPB r/f
- Sn previous concurrence OFFICE - SPB l SPB l IMAB l SPB l SPB l FCSS l OE l NAME CCox/kjc/ij DHoadley SGreene DMartin RPierson ETen Eyck JLieberman DATE 08/11/98 08/13/98 08/18/98 08/18/98 08/18/98 08/19/98 09/03/98 OFFICE OGC Rill:DNMS Rlll:)NMSm NMSS \ l l
! NAME JGoldberg RCaniano BCIEyf&rY *L - CPaperiello \
DATE 09/09/98 09/09/98 09/ f /98 09/ /98 \
l l DOCUMENT NAME: a198-239.lt6 OFFICIAL RECORDS COPY
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4 Draft Document NOT R PUBLIC DISCLOSURE WITHOUT APPROVAL OF THE <
DIRECTOR OF OE l l
in accordance with 10 CF .790 of the NRC's " Rules of Practice," a copy of this letter, its l enclosures and your respons if any, will be placed in the NRC Public Document Room.
Sincerely, 1
Carl J. Paperiello, Director ffice of Nuclear Material Safety I i
a d Safeguards Docket 70-7001 Certificate GDP-1
Enclosure:
Enforcement Conference Meeting Summary cc w/encls: H. Pulley, Paducah General Manager L. L. Jackson, Paducah Regulatory Affairs Manager J. M. Brown, Portsmouth General Manager S. A. Toelle, Manager, Nuclear Regulatory Assurance and Policy, USEC Paducah Resident inspector Office Portsmouth Resident Inspector Office R. M. DeVault, Regulatory Oversight Manager, DOE J. C. Hodges, Paducah Site Manager, DOE DISTRIBUTION Dockets 70-7001,70-7002 NRC File Center Rill NMSS Dir. Off. r/f FCSS r/f K. O'Brien, Rill P. Hiland, Rlli M. Horn Y. Faraz D. Persirko N. Mamish, OE J. Lieberman,OE P. Ting W. Schwink D. Hartland, Rill SPB r/f DOCUMENT NAME: a:\98-239.It8 s Te receive a copy of this document, indicate in the box: "C" = Copy w/o attachment / enclosure ure "N" = "E" = Copy w o(opy OFFICE SPB l SPB l lMAB l SPB ,, lE SPqdi l FCSSf l Of jl NAME CCox/kjc/ij DHoadley SGreene DM'dftiFP RPi(4on ETenEyck JLielerman DATE 08/ /98 08/ /98 08/ /98 08/tr /98 08/1998 08//9/98 0(lT9f98
- 2 -_. = = = ins : === == ns: _ ___
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ii s::er OFFICE OGCl Rlll:DNMS Rill:DNMS NMSS NAME JGokkerg RCdrk c - BClayton CPaperiello DATE 0$/Q//98 0(/( /98 08/ /98 08/ /98 1 OFFICIAL RECORD COPY k [a y %
Draft Document NOT FOR PUBLIC DISCLOSURE WITHOUT APPROVAL OF THE DIRECTOR OF OE
- -. .. . . . _ . . = .-- .
,. e 4
Inhecordance with 10 CFR 2.790 of the NRC's " Rules of Practice," a copy of this letter, its ene sures and your response, if any, will be placed in the NRC Public Document Room.
Sincerely, Carl J. Paperiello, Director Office of Nuclear Material Safety and Safeguards Docket 70-7001 Certificate GDP-1
Enclosure:
Enforcement Con rence Meeting Summary
)
l cc w/encls: H. Pulley, Paducah Ge ral Manager i L. L. Jackson, Paducah ulatory Affairs Manager i J. M. Brown, Portsmouth Ge ral Manager S. A. Toelle, Manager, Nuclear egulatory Assurance and Policy, USEC :
Paducah Resident inspector Office l Portsmouth Resident inspector Office l
R. M. DeVault, Regulatory Oversight Man er, DOE '
J C. Hodges, Paducah Site Manager, DOE i I
DISTRIBUT!ON: 1 Dockets 70-7001,70-7002 NRc File center Rill NMSS Dir. o r/f FCSS r/f I K. O'Brien, Rlli P. Hiland, Rlli M. Horn Y. Faraz D. Persinko N. Marnish, OE J. Lieberman,OE P. Ting W. Schwink D. Harti d, Rill SPB r/f DOCUMENT NAME: a:\98-239.lt6 Tm receive a copy of this document, indicate in the box: "C" = Copy w/o attachment / enclosure "E" = Copy with attach tienclosure "N" = No copy OFFICE SPE) . _ l SPBxJL/ lf- lMAB liC SPB lf SPB l FCSK l OE l NAME CC6kikjc/ij DHdablev SGreene% DMartir1% RPierson ETen Ebck JLieberman DATE 08/l i /98 08/B /98 08) b /98~
NAME JGoldberg GPederson BClayton CPaperiello \
DATE 08/ /98 08/ /98 08/ /98 08/ /98 \
A g ,, OFFICIAL RECORD COPY Draft Document NOT FOR PUBLIC DISCLOSURE WITHOUT APPROVAL OF THE DIRECTOR OF OE
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I UNITED STATES ENRICHMENT CORPORATION PADUCAH GASEOUS DIFFUSION PLANT PRE-DECISIONAL ENFORCEMENT CONFERENCE :
June 16,1998
AGENDA .
A. Restatement of Apparent Violation #1 - 10 CFR 76.85 & 10 CFR 76.9(a)
B. Restatement of Apparent Violation #2 - 10 CFR 76.68 C. Summary D. Assumption ofEmpty Accumulators E. SARUP Limitations and Inaccuracies F. Response to Apparent Violation #1 - 10 CFR 76.85 & 10 CFR 76.9(a)
G. Response to Apparent Violation #2 - 10 CFR 76.68 Appendix A- Chronology
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MUSECO Gi3Mic0 Enerev Compang - - - - - - - - - - - - _ _ _ _ _ _ _ _ _ _ _ _
RESTATEMENT OF APPARENT VIOLATION # 1 -c Part A 10 CFR 76.85 o The SARUP failed to meet 10 CFR 76.85. .
e The SARUP did not perform an adequate analysis of potential accidents and consequences for B 310/310-A and C-315. The SARUP accident analysis did not consider the full range of operation .
operations at the maximum capacity contemplated. Rather, the analysis considered th occur with the accumulators empty which would be the minimum capacity contemplated.
- Had the SARUP accident analysis considered the maximum capacity of the C-310/310-A an accumulators, the consequences would have identified the need for an LCO or required a plan Part B 10 CFR 76.9(a) e The SARUP was not complete and accurate in all material respects as required by 10 CFR 76 6
e The SARUP was not accurate when it stated that the overall consequences for liquid UF Buildings C-310/310-A and C-315 would be on the same order as reported in the Applicat e These statements were material because had the NRC known the size of the error in C-315 accumulators (i.e.,21 tons versus 10 tons) or had USEC accurately assesse would have been identified at least 4 months earlier and resulted in the seismic risk bein
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r.SEC U .. .-c._. - - - - - _ - - - - _ __
RESTATEMENT OF APPARENT VIOLATION # 2 .
e The 10 CFR 76.68 safety evaluation (SE) performed to correct the size of the C-315 accumulator Sectie. 3.5.5 was incomplete. The SE focused on a single accident scenario in SAR Section 4.
not assess the impacts on SAR Sections 4.3.3.1.2,4.6, and 4.9.
- Increasing the size of the C-315 accumulators would increase the accident consequences Section 4.3.3.1.2. Increasing the size of the accumulators would have a direct impact on the to evacuate the system within 5 minutes. Thus, the total material released would be greater t assumed. Also, the assumed release of 1,000 lbs in SAR Section 4.3.3.1.2 is not consistent 4.3.2.4.1 which indicates that the accumulators can be completely filled during cylinder changes.
e SAR Section 4.6 and the source document did not consider the true size UF6 to be present in the accumulators. The presence 6 ofliquid UF could change the seismi accumulators and may have resulted in the capacity change being identified as a USQ.
e Failure of the accumulators during a seismic event could result in releases greater th ,
in SAR Section 4.9.
e USEC failed to evaluate the as-found condition, increased Building C-315 accumula accidents, and continued to operate, with increased consequences without prior NRC approva
SUMMARY
Anparent Viniation #1 10 CFR 76.85 & 10 CFR 76.9(a) e Part A - 10 CFR 76.85 USEC denies the violation. .
e Part B - 10 CFR 76.9(a)
USEC denies the violation.
Apparent Violation # 2 10 CFR 76.68 e USEC maintains that the 10 CFR 76.68 Plant Change Review and Safety Evaluation were ri not adequately documented.
e USEC disagrees that an unreviewed safety question was involved.
IUSEC
e ASSUMPTION OF EMPTY ACCUMULATORS .
The accident analyses in the Application SAR are based on the typical plant operating condition of empty accumulators in Buildings C-310/310-A and C-315. This basis was concluded to be appropriate by USEC, DOE, and the NRC during the initial certification.
Application S AR
. The SAR identifies the maximum capacity of the accumulators:
C-310: 21,000 lbs & 4300 lbs C-315: Two at 42,000 lbs each (the original description of two at 20,000 lbs each was incorrect)
. The SAR describes the accumulators as normally empty consistent with typical operating conditions and states that the accumulators can be temporarily filled if necessary.
. The SAR accident analyses either assume no6 UF is released or that a limited amount of 6 UF is released (e.g.,
1000 lbs) from the withdrawal systems.
. The SAR seismic analyses assumed the accumulators to be empty in determining seismic capacity and in l
I assessing the consequences of predicted failures.
. The SAR establishes that the amount of material assumed +.o be released for the purposes of accidu 't analysis is independent of the maximum capacity of the accumulators.
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ASSUMP'nON OF EMPTY ACCUMULATORS-t t
NRC One=tians
. NRC Questions 4.0Q214 and 215 and USEC's responses clearly addressed the SAR basis an ofempty accumulators. ,
Comnliance Plan Issue 36 '
' The DOE JCO identifies the accumulators as normally empty. A limited amount of U released from postulated seismic failures in the withdrawal systems in Buildings C-310/31 lbs & 2200 lbs, respectively).
The Lawrence Livermore National Laboratory (LLNL) risk study supports the DOE JCO assum accumulators for seismic accident analysis.
Refer to the following items in the chronology:
Revision 1 of SAR Sections 4.3,4.6,4.7,4.9 9/15/95 10/25/95 NRC Questions 4.0Q203,204,214,215,229 USEC responses to Questions 4.0Q203,204,214,215 11/22/95 12/13/95 USEC response to Question 4.0Q229 NRC/USEC meeting to discuss Chapter 4 question responses -
1/17/96 2/19/96 Application Revision 2 USEC revised responses to Questions 4.0Q214,215,229 3/1/96 7 UnisedStanes Enrichment (- *Pornflu"
ASSUMPTION OF EMPTY ACCUMULATORS .
3/20/96 USEC submittal of EDAC reports i 4/9/96 DOE outline for seismic JCO 5/1/96 NRC comments on DOE JCO outline 5/17/96 DOE detailed seismic JCO 5/31/96 Application Revision 3 6/19/96 NRC comments on DOE detailed seismic JCO 7/18/96 USEC submittal of Compliance Plan Issue 36
- 7/26/96 DOE submittal of revised detailed seismic JCO 9/13/96 NRC approval of Compliance Plan Issue 36 in CER 3/17/97 LLNL completes seismic risk study 6/30/97 USEC letter to NRC 7/31/97 USEC letter to NRC l
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YUSEC
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i SARUP LIMITATIONS AND INACCURACIES . :
The SARUP submittals were complete and accurate. Potential limitations or inaccuracies were inntified including the seismic failures in Buildings C-310/310-A and C-315 and the incorrectfisC-315 1. ac in sia capacity used by DOE. The potential significance of these limitations or inaccuracies was also 8/14/97 NRC/IJSEC Senior Management Meeting and 8/18/97 SARUP Submittal i
~
Identifies the "C-315 accumulator capacity & line size," and the "C-310 and C-315 ac as potential limitations or inaccuracles.
10/31/97 SARIIP Submittal Table 1, Item 5, identifies the seismic failures in Buildings C-310/310-A and C-315 evaluated as part of an assessment of dominant seismic risk (6/30/97 and 7/31/97 letters).
Table 1, Item 14, identifies the incorrect values for the C-315 accumulator c in the analysis of a process line failure at compression discharge. Conclud analysis is expected to be small ar.d no changes to the SARUP TSRs are anticipated.
/973CDiDT IISEC/NRC Interactions on "00' Seimmic Mndifications (6/30/97; 7/31/97.12/30/97 IJRFC I f Management lueeting)
Questions whether the seismic modifications to Buildings C-331 and management of seismic risk at PGDP. i
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IUSEC - - - - - - - - - - - --_-_ - __ _
SARUP LIMITATIONS AND INACCURACIES .
Identifies the postulated seismic failures in Buildings C-310/310-A and C-315 and that they ma dominant seismic risk.
. Provides a copy of the LLNL seismic risk study.
. Suspends work on the C-331 and C-335 modifications, thus preserving resources seismic risk and other analyses can be completed.
Refer to the following items in the chronology:
Revision 1 of SAR Sections 4.3,4.6,4.7,4.9 9/15/95 6/30/97 USEC letter to NRC NRC/USEC meeting 7/22/97 NRC/USEC meeting 7/31/97 7/31/97 USEC letter to NRC 8/12/97 NRC letter to USEC NRC/USEC Senior Management meeting 8/14/97 8/l8/97 USEC submittal ofinitial sections of SARUP USEC submittal of the remaining sections of SARUP 10/31/97 NRC/USEC Senior Management meeting 11/5/97 NRC CER for '00' seismic modifications amendment requests 12/8/97 12/30/97 USEC petition requesting Commission review of 12/8/97 Director's Decision ,
'o - a-IUSEC
RESPONSE TO APPARENT VIOLATION #1 .
- Pan A - 10 CFR 76.85 .
No violation of 10 CFR 76.85 occurred: ,
went
. In the apparent violation, the NRC states that an assumption of full accumulators 'during ion a seis would have identified the need for an LCO or a modification. While this may be the case, an assun.
of full accumulators is not the basis of the Application SAR and Compliance Plan dIssue 36. T assumption of empty accumulators for seismic analyses reflects the normal plant operating was fully reviewed and determined to be appropriate by USEC, DOE, and the NRC.
In February 1998, when USEC and the NRC agreed that an empty accumulator assumption appropriate for seismic accident analysis, immediate compensatory actions were t compensatory actions assume the accumulators could be partially filled and establis above the certification basis in the Application SAR and Compliance Plan Issue 36.
Consistent with Compliance Plan Issue 2, the SARUP was prepared by DOE in acc The NRC, DOE, and USEC intended that the SARUP would stisfy the l standards and orders. mpleted requirements of 10 CFR 76.85 when reviewed, approved, and implemented. The NRC has its review and approval of the SARUP and USEC has not implemented the SARUP.
the currently approved certification basis for PGDP.
s 1 i UnitedStates EnrkJunent Caporation l1
RESPONSE TO APPARENT VIOLATION #1 .
Part B - 10 CFR 76.9(a)
No violation of 10 CFR 76.9(a) occurred:
- The 8/18/97 and 10/31/97 SARUP submittals were complete and accurate.
USEC identified potential SARUP limitations or inaccuracies in the 8/14/97 NRC/Ub?C S Management meeting and in the 8/18/97 and 10/31/97 SARUP submittals. These included:
The seismic failures in Buildings C-310/310-A and C-315 (SARUP Section 4.3.2.5).
The incorrect values for the C-315 accumulator capacity and line size used by DOE ,
of a process line failure at compression discharge (SARUP Section 4.3.2.2.12). :
USEC also identified the potential significance of these limitations or inaccuracies: ;
The potential significance of the seismic failures in Buildings C-310/310-A an l identified to the NRC in several letters addressing dominant seismic risk (Junel 1997, and December 30, 1997). The issue was also discussed in the 8/14/97 and 1 L NRC/USEC Senior Management meetings.
The significance of the incorrect accumulator capacity and line size was l 14, of the 10/31/97 SARUP submittal. USEC concluded that the imp was expected to be small and no changes to the SARUP TSRs were anticipated.
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-- ~ m A o USEC A Global Energy Company
RESPONSE TO APPARENT VIOLATION #1 .
. The NRC states in the apparent violation that the 10/31/97 SARUP submittal "was not accurate wLea stat'ed the overall consequences for liquid 6 UF releases from the Building C-310 and Building C-315 w on the same order as reported in the approved SAR."
The violation appears to refer to the following wording in the SARUP:
Fnclosure 't item 4_ ofIISEC I etter GDP 97-01 RR dated R/18/91
" Although the SARUP analysis results in different probabilites and consequences of specific p accidents compared to the existing SAR, the SARUP results are not substantially different than those currently evaluated in the SAR, with the exception of the seismic hazard analyses.
The DOE seismic analyses predict new failures in the C-310 and C-315 withdrawal facilities whic in liquid UF. release. Other failures r.re consistent with and are bounded by results in the SAR. How .
overall consequences are on the same order as reported in the SAR.
The analysis of accidents associated with plant activities and conditions did not identify any sign ,
increase in the probability of occurrence or consequences of previously evaluated accidents. H '
evaluation methodology and criteria are significantly different from what is employed in the current Application SAR. As such, the new analyses represent a significant change in the safe operation."
' Similar to the SAR, the DOE SAR Upgrade assumed the This SARUP statement is accurate. Thus accumulators in Buildings C-310/310-A and C-315 to be empty for the seismic accid based on the assumption of empty accumulators, the overall consequences fr failures reported in SARUP Section 4.3.2.5.3 are similar to those reporte United States Enrichment Corporation 13 a esak,3 pa*rew Company 5
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RESPONSE TO APPARENT VIOLATION #2 (10 CFR 76.68) .
i USEC Position e USEC maintains that PCR-C-97-0867 and SE 97-060 performed to evaluate the SAR Section 3.5 to the Building C-315 accumulator capacity were rigorous but did not adequately docum Compliance Plan Issue 36 and SAR Sections 4.3.4.1.1,4.3.4.1.3,4.6,4.7, and 4.9.
1 e USEC disagrees that an unreviewed safety question was involved: i Correcting the capacity of the C-315 accumulators in SAR Section 3.5.5 did not res change to the plant. Only the words in SAR Chapter 3 were corrected. ;
The correction to SAR Section 3.5.5 did not result in any change to plant operations. The aci are normally empty.
j Correcting the accumulator capacity has no impact on the consequences of any SAR C analyses.
The accident analyses are based on the typical plant operating condition of empty l
accumulators. This assumption is unaffected by the capacity of the accumulators.
' SAR Section 4.3.4.1.1; " Failure of Compre=nion Comnonents" i Same scenarios as described in Section 4.3.3.1.1 for Building C-310. '
6 ;
The maximum 250 lb source term is unaffected by the accumulator capacity beca '
detection system would automatically shut down the Normetex pump.
varion 14 UnitedStates Enrkhneent L
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l
RESPONSE TO APPARENT VIOLATION #2 (10 CFR 76.68) .
i USEC Pnsition (ennt'd) i SAR Section 4.3.4.1 % "Condenner and Accumuintor Failure" l
The analysis states that normally only a small amount 6 of UF is maintained from in the accu ii which minimizes the potential outleakage in the event of a leak at the cylinder connections ( P fatigue failure.
The analysis states that the accumulator can be completely filled if necessary d changeout.
Accumulator failure is characterized by 6 a UF leak from a severed 1/4" instrument line. !
ne maximum release evaluated is 1,000 lbs which is only consistent with an empty a ,
Since the accumulator is empty, the accumulator capacity has no effect on the siz SAR Section 4.3.4.1.3 " Valve and Piotail Failure"
- The maximum release is 660 lbs.
upture l ne analysis states that the worst-case accident scenario considered possible is !
of the drain manifold to cylinder pigtail with the accumulator partially full. i i
I 15 UnitedSuas Ewichmem " r'md' o USEC A Global Energy Company ,
RESPONSE TO APPARENT VIOLATION #2 (10 CFR 76.68)
USEC Position (cont'd)
. The partially filled accumulator assumption ensures sufficient head pressure and liquid UF, piping inventory to make this scenario credible.
The maximum release is unaffected by the accumulator capacity because the 6 UF release detection system would automatically isolate the line. ,
S AR Section 4.6;" Natural Phenomena" npty The EDAC seismic / structural analyses and consequence analyses are based on accumulators.
, The results of these analyses therefore are unaffected by the accumulator capacity.
S_ AR Section 4.7," Consequences ofPostulated Toxic Material Relennes" As discussed for Sections 4.3 and 4.6, the consequences evaluated in this section ar by the accumulator capacity.
SAR Section 4.9. " Residual Risk" As discussed for Sections 4.3 and 4.6, the consequences reported in this sectio the accumulator capacity.
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RESPONSE TO APPARENT VIOLATION #2 (10"CFR 76.68) .
Root Canse
'Ihe root cause for the inadequate documentation in the PCR and SE is similar to that identified in to NOV 97004-10 which stated that the reason for the violation was:
"The reason for the violation was that the level of detail and technical rigor contained within Change Review (PCR) documentation for the proposed changes were inadequate to used to reach the conclusions."
Corrective Actions As noted in USEC's response to NOV 97004-10, USEC took the following actio
" technical rigor contained within the Plant Change Review (PCR) documentation:"
At a PORC meeting on 8/19/97, management standards and expectati ,
detail were discussed. Attendees at this meeting included the managers ofN Safety Analysis.
On 9/3/97, PGDP issued a memorandum to preparers, reviewers, f detail and a i re-emphasizing the management standards and expectations for the technical required to adequately assess proposed plant changes. '
i Refresher training on lessons learned from instances ofinadequate PCRs for all PCR evaluators, reviewers, and approvers was completed on 10/31/97. i t7 UnitedStates Ewichnennt C@lo"
+
RESPONSE TO APPARENT VIOLATION #2 (10 CFR 76.68)
Corrective Actions (ennt'd)
A review of completed PCRs was incorporated into the intemal surveillance pr
.CP2-QA-QS1031, " Conduct ofIntemal Surveillances," to verify that the technical ,
adequate.
i On 9/3/97, in response to NOV 97004-10, the Manager of Engineering d d and- Nuclear to preparers and reviewers of safety evaluations (USQDs) re-emphasizing the manag -
expectations for the level of detail and technical rigor required for the performec !
'Ihe General Manager has initiated a new plant Performance Indicator h PI will(PI). Thi of the quality and technical adequacy of PCRs being performed by variousi PI plant orga present pass / fail performance data based on the PCR reviews i fPCRsperformed will be used by the applicable functional organization managers to continually 10,1998. improve the performed for compliance with 10 CFR 76.68. This new P1 will be implemented by J
. By 7/31/98, PCR-C-97-0867 and SE 97-060 will be revised to specif and SAR Sections 4.3.4.1.1,4.3.4.1.3,4.6,4.7, and 4.9.
l8 UnitedStates EnrkM WW (USEC _ - _ _ _
e RESPONSE TO APPARENT VIOLATION #2 (10 CFR 76.68) .
Mitigating Factors USEC believes that the deficiencies in the PCR and SE are similar to a previous violation th on 8/5/97 (NOV 97004-10)in that:
The PCR and SE were approved during the inspection period for IR 97004. t Til The root cause for the deficiencies is similar to that described in NOV 97004-10 (i.e., the leve and technical rigor contained within the Plant Change Review (PCR) documentation for i
changes were inadequate to fully convey the logic used to reach the conclusions). ;
i The orrective actions taken for NOV 97004-10 are appropriate to address the inadequa ,
in PCR-C-97-0867 and SE 97-060.
. Thus, USEC believes that the inadequacies in PCR-C-97-0867 and SE 97-060 d should !
additional example of NOV 97004-10 since they occurred in the same time and have similar corrective actions.
i L
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APPENDIX A CHRONOLOGY .
Date Dwdntion USEC submits Revision 1 of the Certification Application for NRC review.
9/15/95
. SAR Section 3.4.4 for Building C-310/310-A:
5 "Two UF iiquid accumulators serve the withdrawal system The product accumulator is a 21 capacity nickel-lined tank used in the top product system. The side accumulator a 4,300-lb capacity. The accumulators located on the second floor below the condense volume by " floating" on the drain line..."
. SAR Section 3.5.5 for Building C-315:
"Two 10-ton nickel-lined steel accumulators located downstrea d into system permit gravity flow of the liquid tails material from theficondensers d il material into the accu the tails storage cylinder. Each accumulator can be used for short-term storage of the lique e ta s d in the while a cylinder is valved off or being changed. Normally, only a small h amount es, of UF is accumulators, which merely float on the line ready for immediate use if required (during etc.)..." <
. SAR Section 4.3.3.1.2 on condenser and accumulator failures in C-310/310-A:
"The rupture of a withdrawal system component containing l liquid The UF. could of an instrument line on the accumulator of the fatigue failure of thelldrain filled line from the a worst case in either of these low probability accidents would occur if the accumulato during the change out of UF. drain cylinders at the withdrawal station.
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APPENDIX A CHRONOLOGY .
Date neeription The instrument line break is characterized by a leak from a severed 1/4 in. diameter instance, the UF, is estimated to leak out of the system at a rate of 133 lb/ min. A le be larger depending on the location and type of break, but in no case would the tot 1,000 lb of UF.."
SAR Section 4.3.3.1.3 on valve and pigtail failures in C-310:
"The worst-case accident scenario considered possible at the product withdrawr,1 s rupture of the drain manifold to cylinder pigtail with the accumulators partially full..."
" Assuming a 5 sec response time for the UF. detection unit, ab bility 1 sec closure tim valves, and 10 sec for the cylinder valve closer to operate, the total outleakage for this med accident is 140 lb of UF ..."
. SAR Section 4.3.4.1.2 on condenser and accumulator failures in C-315:
" Tests have shown there has been no appreciable loss iof hmetal tential from either the accumulators. Normally, a minimum inventory is maintained in the accumulator during the to minim ze outleakage in the event of a leak at the cylinder connections or fromiS tion fatigue failure. Howe f
period of switching from one cylinder to another, the acc ,
133 lb/ min.
ne UF. ietection safety system would detect the leak and alarm block in the loc ACR. ne worst case is postulated to be the release of approximately id d to be low." 1,000 lb valves and UF. drain cylinder valve are closed. The probability of such an accident is con IUSEC ~~ - - - - - - - - - - - - _ _ . _ _ _ - - - . _ _ _ _ _ _ _ _ - - - - - _ _ , _ . _ _ _ _ _ _ -_m
APPENDIX A CHRONOLOGY- .
Date %cription
. SAR Section 4.3.4.1.3 on valve and pigtail failures in C-315:
"The worst-case accident scenario considered possible at the tails withdrawal station is a complete rupture -
of the drain manifold to cylinder pigtail with the accumulators partially full..."
"The UF, detection safety system operates identical to that in Section 4.3.3.1.3 and is relied the release of this medium probability accident to 140 lb."
. SAR Section 4.6:
Describes the original seismic /stmetural analyses that included the C-310/310-A components. Evaluates a range of seismic activity between 0.0lg and 0.33g (EBE = 0.18g)
Section 4.6.13 (Table 4.6-3) estimates a total of 720 lbs of gaseous UF. would be released piping in C-310.
. Section 4.6.1.3 concludes that:
"Other system damage caused at the EBE will be inconsequential to on-site or
. SAR Section 4.7:
, Analyzes a 64,000 lbs UF. release for a seismic event based on Section 4.6.
l UnitedStates Earkluna Corpora 23
= re ~ ec ees co m oant
APPENDIX A - CHRONOLOGY .
Dale Deeription
. SAR Table 4.9-1:
. 64,000 lb release for seismic event
. 1000 lb release for fatigue failure of accumulator instrument line or drain line
- 250 lb release for fatigure failure on discharge of Normetex pump
. 140 lb release for fatigue / break of pigtai!
NRC issues questions on the accident analyses related to Buildings C-310/310-A and C-315 and requests 10/25/95 original seismic analyses (Questions 4.0Q203,204,214,215, and 229).
I1/22/95 USEC responds to Questions 4.0Q203,204,214 and 215.
. The responses to Questions 4.0Q203 and 204 were deferred to the SARUP.
4.0Q203 PGDP, {4.3.3.1.2,4th paragraph It is not clear what the total UF. release amount would be if the release rate approached 133 lbs/ mi and the operator could not take mitigative actions which would include isolation and evacuat the system.
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$USEC - ..... .
t APPENDIX A - CHRONOLOGY .
Dalg Deerintion 4.0Q204 PGDP, 4.3.3.1.2,3rd paragraph Does the maximum source term of 1,000 pounds account for the operator error discussed in the last paragraph of 4.3.3.2?
. The responses to Questions 4.0Q214 and 215 are repeated below.
4.0Q214 PGDP, )4.3.4.1.2, page 4.3-40,1st paragraph State the mmimum inventory maintained in the accumulator. If this quantity is 100 pounds, then rephrase the sentence to say: "Not more than 100 pounds of UF. is maintained..."
Response
No material is " maintained" in the accumulator. The accumulator merely floats on the drain line from the condenser to the cylinder. When there is no cylinder to withdraw into, durmg cylinder changeouts, the accumulator pmvides a temporary storage until the next cylinder is connecte When the next cylinder is connected, the accumulator empties.
Application Revision: :
SAR Section 4.3.4.1.2, first paragraph, fourth sentence, will be revised to read as follows:
Normally, no appreciable inventory is in the accumulator which minimizes the potential outleakage in the event of a leak at the cylinder connections or from fatigue failure. ~
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APPENDIX A-CHRONOLOGY
- Date Deeriptinn 4.0Q215 PGDP, $4.3.4.1.2, page 4.3-40,1st paragraph State the highest allowable UF. inventory for the accumulator.
Response
The accumulator sizes are described in SAR Sections 3.4.4 and 3.5.5. 'Ihe accumulators are allowed to be completely filled if necessary during cylinder changeouts. Therefore, the maximum accumulator inventory is limited only by its volume.
Application Revision:
No revisionis required.
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[(USE__C. _ . . _
APPENDIX A CHRONOLOGY .
Date D"'ri P'i""
12/13/95 USEC responds to Question 4.0Q229.
4.0Q229 PGDP, {4.6.1.1, page 4.6-1 Reference is made to an analysis of the above systems' response to a range ofseismic activity from 0.0lg to 0.33g peak ground acceleration. Provide the analysis.
Response
It appears that the reviewer is requesting the EDAC reports prepared to support the development of the DOE 1985 FSAR. These reports are available on site for NRC review. Also see the response to Question 4.0Q10. i Application Revision: ,
No revision required. '
I NRC/USEC meeting held 1/17/96 and 1/18/96 to discuss USEC's responses b to SAR Chal vised 1/17/%
to Questions 4.0Q203,204,214, and 215 were specifically discussed and the NRC requeste (see Questions 4.0Q263 and 4.0Q264 in the NRC letter dated 1/29/96). 4 in the Revision 2 of the certification application is issued which incorporates the SAR Section 4.3.
2/19/96 :
11/22/95 response to Question 4.0Q214.
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. o APPENDIX A - CHRONOLOGY .
Date Deeri,ntion USEC revises the responses to Questions 4.0Q214,215, and 229.
3/1/96 4.0Q214 PODP, 4.3.4.1.2, page 4.3-40,1st paragraph State the minimum inventory maintained in the accumulater. If this quantity is 100 pounds, then rephrase the sentence to say: "Not more than 100 pounds of UF. is maintained..."
Response
No material is " maintained" in the accumulator. The accumulator merely floats on the drain line from the condenser to the cylinder. When there is no cylinder to withdraw into, during cylinder changeouts, the accumulator provides a temporary storage until the next cylinder is connected.I When the next cylinder is connected, the accumulator empties. As stated in Sectiot 3.5.5, the C-315 I Tails Withdrawal Facility contains two 10-ton capacity accumulators. The accumulators are allowed I Therefore, the maximum to be completely filled if necessary during cylinder changeouts. I accumulator inventory is limited by its capacity. I I
Application Revision:
SAR Section 3.5.5, third sentence, will be revised to read as follows:
i Normally, only a small amount of UF. is contained in the accumulators, which merely float I on the line ready for immediate use if required (during cylinder changes, etc.). I ,
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IUSEC
l APPENDIX A - CHRONOLOGY .
Date Dewription l
SAR Section 4.3.4.1.2, paragraph 1, sentence 4, will be revised to read as follows:
1 l
Normally, only a small amount of UF. is in the accumulator. This minimizes the potential 1
outleakage in the event of a leak at the cylinder connections or from fatigue failure. The l
accumulators can be completely filled if necessary during cylinder changeout.
4.0Q115 PGDP, Q4.3.4.1.2, page 4.3-40,1st paragraph State the highest allowable UF. inventory for the accumulator. ,
Response
I The accumulator sizes are described in SAR Sections 3.4.4 and 3.5.5. The product and side I accumulators have capacities of 21,000 lb and 4,300 lb, respectively. The two tails accumulators I each have a 10-ton capacity. The accumulators are allowed to be completely filled if necessary !
during cylinder changeouts. 'Uterefore, the maximum accumulator inventory is limited only by its capacity.
Application Revision:
S AR Section 4.3.4.1.2, first paragraph, fourth sentence, will be revised as indicated irt the .
response to Question 4.0Q214.
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APPENDIX A-CHRONOLOGY Date Deerintion 4.0Q229 PGDP, {4.6.1.1, page 4.6-1 Reference is made to an analysis of the above systems' response to a range ofseismic activity from 0.0lg to 0.33g peak ground acceleration. Provide the analysis.
Response
It appears that the reviewer is requesting the EDAC reports prepared to support the development of the DOE 1985 FSAR. The EDAC reports will be sent under separate cover and are not part of the application. Also see the response to Question 4.0Q10.
Application Revision:
No revision required.
USEC submits the EDAC reports requested by the NRC in Question 4.0Q229.
3/20/96
. KY/G395, prepared in 1981, evaluates the C-310 and C-315 facilities.
. For Building C-310 equipment:
- Damage to the product condensers and side accumulator can occur at 0.10g.
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APPENDIX A - CHRONOLOGY Date neeription
. For Building C-315 equipment:
. Page 7-5 of KY/G395 describes the C-315 accumulators:
"..lIhere are two 10-ton liquid accumulators located downstream from the condensers in the tails withdrawal ;
system that permit gravity flow of the liquid tails material from the condensers into the accumulators and into the tails storage cylinders. Normally, no uranium hexaflouride is maintained in the accumulators, which merely ride on the line ready for immediate use if required..."
- No failures in the condensers or accumulators are predicted.
4/9/96 DOE submits an outline ofits planned justification for continued operation (JCO) with regard to fhilures in Buildir.. C-and C-335 during a seismic event to the NRC for review and comment.
" Status and projected releases from the remaining hazard related facilities are identified to include the co-incident releases that would constitute a part of the bounding consequences."
"The co-incident releases from other predicted failures as determined from current SAR Upgrade analysis >
or from 1985 SAR analysis if available."
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r U _S E C - - ,
APPENDIX A-CHRONOLOGY Date Description 5/1/96 NRC provides comments on the DOE JCO outline.
"4. Potential simultaneous releases from other sources should be identified and considered, including building tie-lines, expansion joints, and accumulators and condensers in buidings C-310 and C-315.
Results should be provided such that the contribuf an from rocker failure and releases from C-331 and C-335 can be identified separately."
5/17/96 DOE submits the JCO to the NRC.
Co-incident releases in Buildings C-310 and C-315, the '000' buildings, and the tic-lines are evaluat with the C-331 and C-335 building failures to include all release sources that may occur during a mismic eve ks into the
. The accumulators in Buildings C-310/310-A and C-315 are identified as normally empty. Product o accumulators during a cylinder change or during an emergency ifcylinder filling is terminated. The .
in Buildings C-310/310-A and C-315 are identified as small.
. Consequences from the failures in Buildings C-310/310-A and C-315 are est mated at:
C-310/310-A: 900 lbs released at 6.7 lbs/sec resulting in 0.4 mgU,0.67 ppm HF C-315: 2200 lbs released at 6.7 lbs/sec resulting in I mgU,1.6 ppm HF
. Consequences considering all failures are determined to be acceptable.
Revision 3 of the certification application is issued which incorporates the SAR Sections 3.5.5 5/31/96 identified in the 3/1/96 response to Question 4.0Q214.
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APPENDIX A CHRONOLOGY Date Deeription 6/19/96 NRC provides comments on the DOE 5/17/96 JCO.
. The description of the piping between the cascade and the fill point should be clarified to say that it outinely contains gaseous UF. above 1 atm and liquid UF..
The " weak links" for the Building C-310/310-A and C-315 accumulators should be identified.
7/18/96 DOE submits Compliance Plan Issue 36 to USEC, and USEC submits it to the NRC.
. The 5/17/96 detailed DOE JCO is referenced directly in the CP Issue 36 JCO on page 3.
7/26/96 DOE submits the revised detailed JCO.
. Essentially unchanged from the 5/17/96 version of the JCO.
. Accumulator failures in Buildings C-310/310-A and C-315 are clarified to be " unrestrained cylinders."
t NRC issues the Compliance Evaluation Report for PGDP.
9/13/96
. CER Section 4.3 for C-310/310-A:
" Two UF. liquid accumulators serve the withdrawal system. The product accumuistor is a 21,000 lb capacity nickel-lined tank used in the top pmduct system. The side accumulator is monel-lined steel l
4,300-lb capacity. The accumulators provide surge volume by " floating" on the drain line..." l i
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USEC c A cm e rar ompaar
APPENDIX A - CHRONOLOGY Dalg Deterintion
- CER Section 4.4 for C-315:
" Two 10-ton nickel-lined steel accumulators are located down stream from the condensers in the tails withdrawal system. Each accumulator can be used for short-term storage of the liquefied tails material while a cylinder is valved off or being changed. Normally, only a small amount of UF is maintained in the .
accumulators, which float on the line ready for immediate use."
. CER Section 5.2.1 identifies the SAR accident consequences for C-310 and C-315:
"...(2) UF6 cylinder pigtail failure - 660 lbs liquid;...(4 j withdrawal compressor (Normetex Pump) failure
- 250 lbs;...(6) condenser / accumulator / withdrawal manifold piping failure - 1,000 lbs liquid;..."
" Based on the information provided in the USEC application, the staff has determined that the scenarios described appear to constitute a reasonable spectrum of postulated accidents and that the safety controls for preventing significant UF 6releases are adequate..."
. CER Chapter 15 related to Compliance Plan issue 36:
"The staff concludes that the justification for continued operation, the plan of action and the schedule are acceptable."
2/14/97 DOE completes preparation of the site-wide SAR Upgrade (KY/EM-174).
. Section 2.3.4.3.1.3 for C-310/310-A:
"Two UF, liquid accumulators serve the withdrawal system. The product accumulator is a 10.5-ton (9.5-t) '
capacity, nickel-lined tank used in the top product system. The side accumulator is monel-lined steel w UnitedStates Enrichment Corporanon 34 r - . , c.--,
APPENDIX A CHRONOLOGY Date Deeriptin i a 2.1-ton (1.9-t) capacity. He accumulators located on the second floor below the condensers provide surge volume by " floating" on the drain line.. "
- Section 2.3 ~.3.1.5 for C-315:
"Two 10-ton (9-t) nickel-lined steel accumulators located downstream from the condense withdrawal system permit gravity flow of the liquid tails material from the condensers into the accumulators and into the tails storage cylinders. Each accumulator can be used for shon-term storage ofliquefied tails material while a cylinder is valved off or being changed. Normally, only a small amount o' '1F. is maintained in the accumulators, which merely float on the line ready for immediate use if required ( ring cylinder changes, etc.)..."
. Section 3.4.2.1.2.13 for scenario of process line failure at compression dischvge:
ne release was modeled as resulting from a one-inch diameter breach in the bottom of a venica tank 60 inches in diameter and 120 inches tall containing 21,000 lbs ofliquid UF..
.tal He total flow rate was estimated to be about 8 lb/sec (1.3 lb/sec vapor,6.7 lbs/sec liquid) resultin release of about 25,000 lbs.
. Section 3.4.2.1.6.3 for a seismic event:
"...During this withdrawal phase, the source term includes the contents of the condensers and back '
the cylinder being filled. No UF. would be released from the accumulators, which'the are normally 'mpt during the withdrawal operation. The contents of the accumulator are bounded by the contents ,
cylinder."
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APPENDIX A - CHRONOLOGY Date Deerintion "The entire contents of the condensers (two in building C-310/310-A and three in building C-315) are assumed to be released into the withdrawal buildings in a very short time (120 s or 2 minutes). The total amount ofliquid UF. released into building C-310/310-A would be about 1500 lb (683 kg), with about 3600 lb (1677 kg) released into C-315..."
" Approximately 1100 lb (500 kg) would be released from the 48X cylinder located in Bldg. C-310/310-A, with slightly more,1110 lb (505 kg) released from the 48G cylinder located in Bldg. C-315..."
Lawrence Livermore National Laboratory (LLNL) completes preparation of seismic risk study for DOE.
3/17/97 "In addition to the four process buildings, gaseous and liquid UF. is contained in cylinders inside le ildings C-315, C-310a, C-333A, C-337A, and C-360 where feed, product, or tails material is introdu d or .
withdrawn from the system. Some liquid-filled cylinders are also located outside these buildings.. in a ss temporary basis, liquid UF. may also reside in the accumulators used to control the inventory in the pre systems. This study did not consider the contributions to the source terms from possible damage toi cylinders or other facilities. This omission is judged to be insignificant to the risk estimates becau low probability of an earthquake occurring simultaneously with high inventories in containers that arc vulnerable to damage..."
ity 4/13/97 Problem Report PR-CO-97-1929 written. The APSS identifies the potential for the C-315 accumulators to h greater than 10 tons as a result of field walkdowns.
4/23/97 A calculation of accumulator volume, EV-C-820-97-014, is initiated.
4/25/97 EV-C-820-97-014 is completed which concludes that the capacity of each C-315 accumulator The system engineer recommends a review of structural / floor load calculations.
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APPENDIX A-CHRONOLOGY Date Dm ription 4/25/97 PCR-C-97-0867 (10 CFR 76.68 review of as-found accumulator volume) is initiated.
accumulator volume)is initiated.
RAC 97C0105 to change the SAR Section 3.5.5 discussion of accumulator capacity is initiated.
4/28/97 RAC 97C0105, PCR-C-97-0867, and SE 97-060 are approved by the PORC.
6/25/97
. SAR Section 3.5.5 is revised to read as follows:
the i "Two approximately 21-ton nickel-lined steel accumulators located downstream from the condensert he tails withdrawal system permit gravity flow of the liquid tails material from the condensers ints i accumulators and into the tails storage cylinder. Each accumulator can be used for short-term storage on liquefied tails material while a cylinder is valved off or being changed. Normally, only a small amount UF,is maintained in the accumulators, which merely float on the line ready for immediate use if (during cylinder changes, etc.)..."
hat He USQD evaluates the impact on SAR Section 4.3.4.1.2 (condenser and accumulator i to fail ,
there is no adverse impact on the probability of a failure, the assumed size of the leak, the leak mitigation, or the amount released. Concludes that no USQ is involved.
The PCR and SE do not address the potential impacts on Compliance Plan Issue 36 ,
(failure of compression components),4.3.4.1.3 (valve and pigtail failure),4.6 (seismic 4.9 (residual risk).
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US a esa ec-...wCamnany
e o APPENDIX A - CHRONOLOGY Date Dewription 6/30/97 USEC submits letter GDP 97-0101 to the NRC.
. Questions whether the seismic modifications to Buildings C-331 and C-335 are an effective elemen management of seismic risk at PGDP.
. "The DOE upgraded analysis identifies a seismic vulnerability for the liquid UF. condensers and accumulators at the withdrawal facilities. These facilities would not benefit from the modifications being made to the C-331 and C-335 buildings, yet these postulated failures may constitute a dominant risk sequence for the EBE. USEC is currently reviewing these analyses."
- Provides a copy of the LLNL seismic risk study.
. Suspends work on the C-331 and C-335 modifications, thus preserving resources until evaluation seismic risk and other analyses can be completed.
7/14/97 The NRC Resident Inspector conducts an exit meeting at PGDP for a routine inspection performed fro A violation of 10 CFR 76.68(a) is identified conceming deficient safety evaluations that were approv 6/20/97 concerning SAR changes: (a) an increase in the possession limits; and (b) dcletion of the five-yea frequency for the cell trip function.
7/22/97 NRC/USEC meeting at PGDP to discuss SARUP. Potential limitations with the SARUP submitta Inaccuracies in SAR Chapter 3 are discussed in detail.
NRC/USEC meeting to discuss inaccuracies in SAR Chapter 3.
7/31/97
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APPENDIX A - CHRONOLOGY .
Date Dewrintion 7/31/97 USEC submits letter GDP 97-0136 to the NRC in followup to 6/30/97 letter.
. Amends USEC's 4/23/97 amendment request related to the USQs associated with the Buillding C-331/C-335 seismic modifications.
. Requests Compliance Plan Issue 36 be revised to include consideration of SARUP-identified seismic failures.
8/5/97 NRC issues Inspection Report 70-7001/97004 which contains violation NOV 97004-10.
8/12/97 NRC letter to USEC.
"Your SARUP is due to the NRC by August 17,1997, the date to which you are committed accora 1 to
- h the Compliance Plan. You should include in your submittal a discussion of any SARUP limitations, as knmvn or suspected inaccuracies, along with your plan to rectify these deficiencies..."
8/14/97 NRC/USEC Senior Management meeting.
. The status of the SAR Update is discussed.
t
. The following are identified as known limitations or inaccuracies against SARUP Section 4.3.2 and are discussed at the meeting:
"PGDP C-315 accumulator capacity & line size" "PGDP C-310, C-315 accumulators during EBE"
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APPENDIX A CHRONOLOGY Date Description 8/l8/97 USEC submits initial sections of SARUP by letter GDP 97-0147.
. In Enclosure 1, the following are identified as known limitations or inaccuracies against SARUP Section 4.3.2:
"PGDP C-315 accumulator capacity & line size" "PGDP C-310, C-315 accumulators during EBE" 9/4/97 USEC responds to NOV 97004-10. Commits to completing corrective actions by !!/1/97.
USEC submits remaining sections of SARUP by letter GDP 97-0188.
10/31/97
. Scenarios are similar to DOE SAR Upgrade (KY/EM-174).
ibmittal:
. Table 1 identifies limitations, inaccuracies, and required modifications associated with the SARU1 Table 1. Item 5 (S ARIIP Sectinns 'LI S 9.1.3;3.15.4.5 4.315)
The DOE SAR Upgrade also concludes that the UF. condensers, accumulators, and the Normetex pum, discharge piping in both the C-310A and the C-315 withdrawal facilities do not have adequate capacity t ,
withstand the evaluation basis earthquake.
The resolution of the C-331 and C-335 seismic modifications and the other seismically-induced failures identified by the DOE SAR Upgrade are being evaluated by USEC as part of an assessment of dominan seismic risk at PGDP. (Refer to USEC Letters GDP 97-0101, dated June 30,1997, and GDP 97-0 July 31,1997)."
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APPENDIX A - CHRONOLOGY Date Descrintion Table 1 Item 14 (SARIIP Sectinns 4.3 ? ? 1; 4.3 ?_? 12)
"The DOE SAR Upgrade (KY/EM-174) performed threshold analyses to determine the amount of'TF.
release necessary to reach Evaluation Guideline consequences at the site boundary. One case analyzed ;
C-315 accumulator but used incorrect values for the capacity and a size of the discharge line. The impa. :
on the threshold analysis is expected to be small and no changes to the SARUP TSRs are anticipated.
The affected consequence analysis will be revised to use the correct values for accumulator capacit size. The results of the revised calculations, including any necessary changes to the SARUP, will be submitted to the NRC by December 31,1998."
NRC/USEC Senior Management meeting.
11/5/97 the NRL Related to the 4/23/97 and 7/31/97 amendment requests for the '00' seismic modifications, 'ified inUSEC as needs any additional information related to the dominant seismic risk issue and the seismic fail SARUP. The NRC responds that no additional infonnation was needed at that time.
NRC issues the CER for the '00' seismic modifications amendment requests.
12/8/97 Staff review of(a) final design- (b) 3 IISOs (c) S ARIJP seismic analysis. (d) undated seismic ha7ard "Therefore, the staff recommends approval of the schedule to complete the modifications fi 18 m the staff approves the USQs (II(b)) and recommends denying that the schedule be based on s conditions described in Sections II(a) [ staff review of final design], II(c) [ review of SARU analyses], and II(d) [ review of updated seismic hazard} above." Items in [] addedfor clarity.
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APPENDIX A CHRONOLOGY Date Deeription 11NT. Study "He study that the certificate holder wishes to add to the JCO reviewed the health risks to workers and to the public from potential UF. releases due to a seismic event. The staff did not review the report, nor was it requested to review the report. The staff has not relied on this repon to reach its conclusions. Sinc amendment request, as proposed, implies that the staff reviewed and approved the repon as part of the approval of the amendment will not include the reference to the report and this request is denied."
- 2/30/97 USEC files a petition requesting Commission review of those items denied in the 12/8/97 97-0224.
USEC's petition describes the SARUP-predicted failures in the liquid UF. withdrawal are 310/310-A and C-315.
NRC issues questions on the SARUP submittals.
2/5/98 "Our review of your application has identified additional infom1ation that is needed. The initial review h verified the statement in yc.ur letter (GDP 97-0244) to NRC Secretary, John Hoyle, dated Decem 1997, that the liquid withd.awal areas of Buildings C-310 and C-315 at the Paducah Gaseous Diff are susceptible to seisnCcally induced damage. You further implied that analysis of modific and C-315 is unds way. Your letter further implied that the C-310 and C-315 may contribute s to the overall seismic risk at Paducah. Based on this information, the staff requests answers questions, as they apply to Buildings C-310 and C-315:
1.
Provide a detailed description of the structural and equipment failures that occur, as liste 3.15.8, " Seismic Capacities of Buildings C-310/C-310-A Piping Equipment and Compo Table 3.15-9 " Seismic Capacities of Building C-315 Piping Equipment and Coraponents."
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9 APPENDIX A - CHRONOLOGY :
Date Dewription
- 2. In terms of releases, provide an analysis of and describe in more detail the potential consequences, both onsite and offsite, associated with those failures. Include the bases of the assumptions made in Section 4.3.2.5.3.c," Source Term Analysis."
- 3. Describe the analysis of modifications that are underway. When will those analyses be completed and provided to NRC?
- 4. Provide a justification for continued operation of these buildings, given their susceptibility to seismically-induced damage and the potential consequences. Consider in your answer your responses to the above questions."
Week of Numerous telephone conversations between NRC and USEC are conducted to discuss thisthe issue. The p. ,ary i JCO for 2/16/98 discussed is how much UF. should be assumed to be in the accumulators. The NRC informs Compliance Plan issue 36 is not applicable to this issue.
with 10 USEC verbally notifies the NRC of potential nonconservative assumptions in the SARUP and S AR in accordat 2/19/98 CFR 76.9.
2/20/98 USEC provides written notification in accordance with the requirements of 10 CFR 76.9 by letter G
" Question 2 of the NRC's February 5,1998 letter requests USEC to provide the bases for the a assumptions. Preliminary information from our research into the assumption bases indicates that the so term assumed in the SAR Update for the postulated seismic failures in the liquid withdrawal areas ma nonconservative. As identified above, the UF. release in Buildings C-310/310-A and C-315 is assume the SAR Update to be about 1500 lbs (683 kg) and 3600 lbs (1677 kg), respectively. ' side In Building C-1 A, the total capacity of the 3 condensers is about 1500 lbs (683 kg) and the capacities ofC-the product accumulators are approximately 21,000 lbs (9525 kg) and 4300 lbs (1950 kg), respectively. In Builds 4' - - - -"-
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g A h H APPENDIX A - CHRONOLOGY ,
Date Devription 315, the total capacity of the 3 condensers is about 2000 lbs (907 kg) and the capacity of the two accumulators is approximately 40,000 lbs (18,050 kg) each. Based on our preliminary reviews of the product and tails withdrawal operations in these buildings, the total release assumptions in the SAR Update may be nonconservative considering the potential for higher volumes ofliquid UF. to exist in the two overall systems including the condensers, accumulators, and connecting piping. In addition, the consequences of postulated seismic failures currently reported in Chapter 4 of the Application SAR and Compliance Plan Issue 36 may be increased. Although it may be unreasonable to assume that all of the above components are filled to capacity for the analysis of the Evaluation Basis Earthquake (EBE), our preliminary review of the operating information suggests that consideration of operating volumes greater than the SAR Update assumptions of 1500 lbs (683 kg) in Building C-310/310-A and 3600 lbs (1677 kg) in Building C-315 may be appropriate."
2/24/98 NRC/USEC telephone conversation. USEC informs the NRC that a postulated seismic event resultin UF. from the Building C-310/310-A and C-315 accumulators was outside the SAR accident analysis.
2/25/98 USEC requests enforcement discretion in letter GDP 98-0031.
"In the process of responding to NRC questions on USEC's October 31,1997, SAR Update (SARUF submittal, a review of operations in the Building C-310/C310-A product and Building C-315 tails withdrawal areas has concluded that the current release assumptions made in the SAR Section 4.6 a ,
of the consequences of postulated seismic failures are no longer valid. Specifically, the SAR analy assumes only a limited UF release from the C-310 withdrawal facility. However, during the nonnal course of operations in Buildings C-310/310-A and C-315, these facilities contain varying amounts ofliq depending on withdrawal rates and maintenance and operational activities. The amount of be released from these facilities during a postulated seismic event exceeds that assumed in the curre analysis."
UnitedStates Enrichment Corporation 44 Y TQ y Ud A Global Energy Company
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APPENDIX A - CHRONOLOGY :
Date Dec.cription 2/26/98 NRC issues questions on USEC's 2/25/98 request for enforcement discretion.
"(1) Proposed Commitments do not include a commitment to control and minimize at all times " the t '6 inventory in the C-315 on-line accumulator. As proposed the limit is effectively the full volume one accumulator.
(2)
No compensatory actions are proposed for limiting accumulator inventory in Building C-310/310-A (purge and product withdrawal building). This is supposedly based on low probability of having inventory present. 'Ihat is an unacceptable basis given the supporting information in the JCO. Must propose limits and a mechanism to ensure that these limits are adhered to."
USEC responds to the NRC's 2/5/98 questions by letter GDP 98-0019.
2/27/98 USEC responds to the NRC's 2/26/98 questions by letter GDP 98-0036.
2/27/98 NRC/USEC meeting to discuss the NRC comments on the request for enforcement discretion.
3/3/98 USEC responds to the NRC comments from the 3/3/98 meeting by letter GDP 98-0041.
3/5/98 98-USEC submits an action plan for the postulated seismic failures in Buildings C-310/310-A and C-3/11/98 0046.
"As a result of analyses performed in response to the NRC's February 5,1998 request for infor detennined that conservative assumptions may not have been utilized in the SAR Update acc and, as a result, the potential consequences of postulated seismically-induced failures in t withdrawal facilities (Buildings C-310/310-A and C-315) could be increased over those previou
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Date Deeription in the SAR Update. USEC also concluded that the consequences of postulated seismic failures could be more severe than currently reported in Chapter 4 of the Application SAR and Compliance Plan Issue 36.
"Following a thorough evaluation of both the safety and operational concems involved, the best cour action for final resolution of this issue is to prevent the occurrence of the predicted seismic failures in the withdrawal areas of Buildings C-310/310-A and C-315. The postulated failures in these facilities have been determined to le the dominant centributor to overall seismic risk at PGDP. USEC has, therefore, conclud that modifying this equipment to increase its seismic capacity is the most effective and cost-Justifiabl means of reducing the overall risk to workers and the offsite public of postulated seismic events at P !
The Commission denies USEC's 12/30/97 petition requesting Commission review of the Director's decision.
3/19/98
" According to USEC, the SARUP information indicates tl .at areas of two other building 4 (i.e., two p withdrawal buildings, Buildings C-310 and C-315) are also susceptible to seismic-induced damage.
petitioner argues that the SARUP information shows that the planned modifications are not, effective in reducing the seismic risk at PGDP since the C-331 and C-335 failures do not dominat risk at the site..."
"It is possible that the staff's review of the SAkUr could result in the requirement for modificati buildings and equipment; however, this has no bearing on the currently planned modificat above, the presence of greater risks from other sources would not obviate the need for th upgrades..." .
USEC submits a revised request for enforcement discretion by letter GDP 98-0060.
3/27/98 NRC requests USEC consent to Confirmatory Order.
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Date Deerintion 4/1/98 USEC submits consent to Confirmatory Order by letter GDP 98-0066.
4/22/98 NRC issues Contirmatory Order Modifying Certificate.
5/7/98 NRC issues Inspection Report 70-7001/98006 (DNMS).
5/28/98 NRC issues " Apparent Violation of 10 CFR 76.85 Concerning the Seismic Accident Analysis in the Paducah Certificate Amendment Request, Dated August 18,1997, Update of the Application Safety Analysis Report, and Apparent Violati of 10 CFR 76.68 Concerning the C-315 Withdrawal Accumulators Size" l
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