ML20206R781
| ML20206R781 | |
| Person / Time | |
|---|---|
| Site: | Portsmouth Gaseous Diffusion Plant, Paducah Gaseous Diffusion Plant |
| Issue date: | 05/10/1999 |
| From: | Toelle S UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | Paperiello C NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| GDP-99-0081, GDP-99-81, TAC-L32043, TAC-L32044, NUDOCS 9905200199 | |
| Download: ML20206R781 (19) | |
Text
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4 Y
d r USEC A Global Energy Company May 10,1999 GDP 99-0081 Dr. Carl J. Paperiello Director, Office of Nuclear Material Safety and Safeguards Attention: Document Control Desk j
U.S. Nuclear Regulatory Commission j
Washington, D.C. 20555-0001 Pad :: bh Gaseous Diffusion Plant (PGDP)
Pora.a,uth Gaseous Diffusion Plant (PORTS)
Dacket Nos. 70-7001 & 70-7002 Response to NRC Request for Additional Information - Safety Analysis Report Update (TAC Nos. L32043 and L32044)
Dear Dr. Paperiello:
I By letter dated June 1,1998 (see the reference), the Nuclear Regulatory Commission (NRC) forwarded to the United States Enrichment Corporation (USEC) various questions on the certificate amendment requests to Update the Application Safety Analysis Reports (SARUP) for the Paducah, Kentucky and Portsmouth, Ohio gaseous diffusion plants.
USEC's responses to a number of the NRC questions / comments from the June 1,1998 NRC letter are provided in Enclosure 1. Enclosure 2 provides a status of the response to each of the NRC questions / comments on the SARUP submittals. Responses to the remaining questions / comments will be submitted at a later date.
Ifyou have any questions on USEC's responses, please call Mark Smith at (301) 564-3244. There are no new commitments contained in this submittal.
Sincerely, j
S. d.
/
l Steven A. Toelle 4{}
q Nuclear Regulatory Assurance and Policy Manager C0 N
[
9905200199 990510
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PDR ADOCK 07007001 C
PDR 6903 Rockledge Drive, Bethesda, MD 20817-1818 Telephone 301-564-3200 Fax 301-564-3201 http://www.usec.com OfBces in Livermore, CA Paducah, KY Portsmouth, OH Washington, DC 1
e -
a Dr. Carl J. Paperiello-May.10,1999 GDP 99-0081, Page 2
Reference:
. Letter from Charles Cox (NRC) to Mr. James H. Miller (USEC), "Paducah and Portsmouth Certificate Amendment Requests - Update of the Application Safety Analysis Reports (TAC Nos. L32044 & L32043)," dated June 1,1998.
Enclosures:
1.
Responses to Chapter 3 - 11(c-f),16(c-f),17 (c,d),18(c,d),22 (a,b,d-f);
Chapter 4 - Q10, Q15, Q23 from the June 1,1998 NRC Request for
. Additional Information - Safety Analysis Report Update (TAC Nos. L32043 and L32044).
2.
Status of Responses to NRC Questions / Comments on SARUP cc:
Mr. Robert C. Pierson, NRC HQ NRC Region III Office NRC Resident Inspector-PGDP NRC Resident Inspector-PORTS Mr. Randall M. DeVault (DOE) 1
1 I
i Enclosure l GDP 99-0081 Responses to Chapter 3 - 11(c-f),16(c-f),17 (c,d),18(c,d),22 (a,b,d-f);
Chapter 4 - Q10, Q15, Q23 from the June 1,1998 NRC Request for Additional Information -
Safety Analysis Report Update (TAC Nos. L32043 and L32044)
p
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. SARUP Q&R - PGDP/ PORTS May 10,1999 Chapter 3 - Q11 (NRC 6/1/98 Letter)
PORTS - f 3.8.2.8 The description should include a diagram identifying key components.
a.
b.
A numerical analysis should be included demonstrating that the probability of the (now mitigated) system not performing its safety function is incredible (less than IE-6).
The description should explain terminology and location of sensors; ambiguous terms c.
include actuation pressure and emergency autoclave operation switch, d.
The inter-operabilitybetween this system, the emergency autoclave bypass switch, and the autoclave shcIl high pressure containment system should be explained better.
It is not clear how this system can receive an AQ designation,as it complementsa Q system e.
and prevents the potential for significant offsite effects (i.e., a Q system requirement); the AQ designation should be explained.
f.
Information should be provided to explain how this unit functions without electrical power, as stated in the functional requirements.
Response
a.
Current SAR Chapter 3 provides diagrams for various SSCs. Diagrams will also be
-included in the rewrite of SAR Chapter 3 to support SARUP Section 3.8, the SARUP Chapter 4 accident analysis, and the SARUP TSRs.
b.
A numericalanalysis was not performed to demonstrate that the system would perform its safety ftmetion at any particularfailure frequency. The capability of SSCs to perform their safety function was determined in the SARUP based on engineering analyses, engineering judgement,and plant operating history (supplemented in some cases with qualitative fault tree analyses). This process identified the SSC quality and operability requirements to provide adequate assurance that the SSC could be expected to perform its safety function.
The process used in the SARUP is consistentwith the approach described in Section 1.d of the Plan of Action and Schedule for Compliance Plan Issue 2. There were no criteria in the SARUP analyses for demonstratingthat the probabilityof a system not performingits safety function is incredible (less than IE-6).
The description provided is sufficiently clear. The " Safety Function Analysis" section l
c.
provides the actuation pressures for both the autoclave locking ring interlock system and the l
autoclave high pressure containment shutdown system. In addition, the emergency l
autoclave operation switch allows bypass of the isolation signal to the hydraulic system l
provided by the autoc!?ve high pressure containment shutdown system. Chapter 3 of the l
SAR provides a more complete description of the system. Facility and process descriptions l
will be included in the rewrite of Chapter 3, as required, to support the SARUP Accident l
Analysis (Chapter 4) and the SARUP Safety System Classification (Section 3.15/3.8).
l d.
The description provided is sufficientlyclear. A more detailed description of the autoclave l
and its operation is provided in the SAR Chapter 3. Facility and process descriptions will l
be included in the rewrite of Chapter 3, as required, to support the SARUP Accident l
Analysis (Chapter 4) and the SARUP Safety System Classification (Section 3.15/3.8).
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SAR,UP QBgR - PGDP/ PORTS May 10,1999 l
l e.
The operator is prohibited from taking action to open the autoclave, using the autoclave l
containment bypass switch, by administrative controls requiring that the autoclave high l
pressure alarm condition be cleared. This condition cannot be achieved until any release l
is terminatedand the autoclave pressureis below 15 psig. As such, the Autoclave Locking l
Ring Interlock System prevents an operator action to remove the autoclave from l
l containment inappropriately and provides for personnel protection against opening the l
i autoclave when internal pressure might result in shell movement that could injure personnel. l As such, it is appropriately classified as an "AQ" SSC.
l f.
This system is a simple pressure actuated interlock switch. As such, it actuates whether j
there is power or not. Additionally, loss of power would render the hydraulic system l
inoperable and unable to open the shell.
l SARUP Revision:
No revision required.
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SARUP Q&R - PGDP/ PORTS' May 10,1999 Chapter 3 - Q16 (NRC 6/1/98 letter)
PGDP/ PORTS - Q3.15/3.8.3.4 The description should include a diagram iientifying key components, locations, power a.
supply systems, control power supply, etc.
b.
A numerical analysis should be included demonstrating that the probability of the (now mitigated) system not performing its safety function is incredible (less than IE-6).
c.
Numericalvalues should be provided for the system pressures and the relief valve / rupture disk settings. There should include normal pressure, MAWP, failure pressure (estimated),
and relief set pints.
d.
A lock-out/ta g-outprogram should be identified for those relief valves / rupture disks that are separated from the coolant system by a manual block valve, The description of the freezer /sublimersystems contains several apparent discrepanciesthat e.
should be cluitied. Also, a numerical analysis should be presented showing the source term from potential events.
f.
The destination of the downstream piping from the relief devices should be identified (i.e.,
relief to the roof, to a scrubber).
't
Response
We believe that the appropriate place for such diagrams is in the facility and process j
a.
descriptions. In general, diagrams are provided in the current Chapter 3, Facility and Process Description. Diagramswill be included in the SAR Chapter 3 rewrite currently in progress as required to support the SARUP Accident Analysis, Chapter 3.8 SSC information and the TSRs.
b.
A numericalanalysis was not performed to demonstrate that the system would perform its safety function at any particular failure frequency. The capability of SSCs to perform their safety function was determined based on engineering analyses, engineeringjudgement, and plant operating history (supplemented in some cases with qualitative fault tree analyses).
This process identified the SSC quality and operability requirements to provide adequate assurancethat the SSC could be expected to perform its safety function. The Compliance Plan, Issue 2, Plan of Action and Schedule, Section 1.d) states "A description of systems, structures and components determined to be safety class or safety significant will be developed based on the results of the hazard and accident analysis. This will include identification of the support systems, functional requirements, performance criteria necessary to provide reasonable assurance that the functional requirements will be met, and identificationof assumptions needing Technical Safety Requirement coverage." As such, there was no criteria in the SARUP analyses for demonstrating that the probability of a system not performing its safety function is incredible (less than IE-6).
The information on system settings is provided in Chapter 3 of the Application SAR.
l c.
Facility and process descriptions will be included in the rewrite of Chapter 3, as required, l
to support the SARUP Accident Analysis (Chapter 4) and the SARUP Safety System l
Classificatim (Section 3.15/3.8). These are " Code" vessels and, as such, the failure point l
is well above the system relief setting.
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g SAR,UP Q&R - PGDP/ PORTS May 10,1999 d.
The use of lockout /tagout (LOff0) in plant operations is described in Chapter 6 of the l
Certification SAR and in plant procedures. The LOfrO procedures are utilized in l
evolutions involving these valves or the system is placed in a condition that does not require l the relief system to be operable (e.g., draining the system).
l e.
We are not aware of any significant discrepancies in this section; however, it is not a l
completedescriptionof the freezer /sublimersystems. The system description is contained l
in Chapter 3 of the SAR. Facility and process descriptions will be included in the rewrite l
of Chapter 3, as required, to support the SARUP Accident Analysis (Chapter 4) and the l
SARUP Safety System Classification (Section 3.15/3.8). The hazard analysis (PrHA) l identified a number of potential accident scenarios involving the freezer /sublimers.
l However, they were qualitatively identified to be below the PSOA screening threshold l
based on the fact that the UF6 is always in the solid / gas phase with relatively low pressures l
and temperature. As such, there were no source tetms calculated for any of the l
freezer / sublimer release scenarios.
l f.
The freezer / sublimer relief device vents to the cascade; as such, there is no release of UF.
l to the general area. The coolant system reliefis to the general area; however, there is no l
potential for other than standard industrialhazards from the release of coolant. The release l
of coolant will not prevent operators from performing any credited safety function. In view l
of the above, the location of the coolant vent is not required in this section.
l SARUP Revision:
No revision required.
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f.
u' SARU,P Q&It - PGDP/ PORTS May 10,1999 Chapter 3 - Q17 (NRC 6/1/98 letter)
PGDP/ PORTS - Q3.15/3.8.3.5 l-a.
The description should include a diagram identifying key components, locations, power l
supply systems, control power supply, etc.
b.
A numerical analysis should be included demonstrating that the probability of the (now mitigated) system not performing its safety function is incredible (less than IE-6).
4 c.
The number of these systems should be identified.
d.
The total volume and weight of these systems should be identified.
Response
We believe that the appropriate place for such diagrams is in the facility and process a.
descriptions. In general, diagrams sre provided in the current Chapter 3, Facility and Process Description. Diagrams will be included in the SAR Chapter 3 rewrite currently in
- progress as required to support the S ARUP Accident Analysis, Chapter 3.8 SSC information and the TSRs.
b.
A numerical analysis was not performed to demonstrate that the system would perform its safety function at any particular failure frequency. The capability of SSCs to perform their safety function was determined based on engineering analyses, engineeringjudgement, and plant operating history (supplemented in some cases with qualitative fault tree analyses).
This process identified the SSC quality and operability requirements to provide adequate assurancethat the SSC could be expected to perform its safety function. The Compliance Plan, Issue 2, Plan of Action and Schedule, Section 1.d) states "A description of systems, structures and components determined to be safety class or safety significant will be developed based on the results of the hazard and accident analysis. This will include identification of the support systems, functional requirements, performance criteria necessary to provide reasonable assurance that the functional requirements will be met, and identificationof assumptions needing Technical Safety Requirement coverage." As such, there was no criteria in the SARUP analyses for demonstrating that the probability of a system not performing its safety function is incredible (less than IE-6).
The number of freezer /sublimersystems are identified in Chapter 3 of the SAR: there is one l
c.
high-high weight trip per freezer / sublimer. Facility and process descriptions will be l
included in the rewrite of Chapter 3, as required, to support the SARUP Accident Analysis l
(Chapter 4) and the SARUP Safety System Classification (Section 3.15/3.8).
l d.
The total weight of these systems is described in Chapter 3 of the S AR; the volume has no l
safety ' significance. Facility and process descriptions will be included in the rewrite of l Chapter 3, as required, to support the SARUP Accident Analysis (Chapter 4) and the l
l SARUP Safety System Classification (Section 3.15/3.8).
l
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SARUP Revision:
l No revision required.
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E SARUP Q&R - PGDP/ PORTS May 10,1999 Chapter 3 - Q18 (NRC 6/1/98 letter)
PGDP/ PORTS - f 3.15/3.8.3.6 The description should include a diagram identifying key components, locations, power a.
supply systems, control power supply, etc.
b.
A numerical analysis should be included demonstrating that the probability of the (now mitigated) system not performing its safety function is incredible (less than IE-6).
c.
There should be a better explanation of the ammeter indications and the operator response to/ investigation of" inexplicable change".
d.
It would seem that the motor load indicators are essential for detecting and avoiding compressor surge events, precursors to releases producing off-site effects. Consequently, the text should explain the basis for an "AQ" designation instead of a "Q" designation.
Response
a.
We believe that the appropriate place for such diagrams is in the facility and process descriptions. In general, diagrams are provided in the currert Chapter 3, Facility and Process Description. Diagramswill be included in the SAR Chapter 3 rewrite currently in progress as required to support the S ARUP Accident Analysis, Chapter 3.8 SSC information and the TSRs.
b.
A numericalanalysis was not performed to demonstrate that the system would perform its safety function at any particular failure frequency. The capability of SSCs to perform their sa:
function was determined based on engineering analyses, engineeringjudgement, and plant operating history (supplemented in some cases with qualitative fault tree analyses).
This process identified the SSC quality and operability requirements to provide adequate assurancethat the SSC could be expected to perform its safety function. The Compliance Plan, issue 2, Plan of Action and Schedule, Section 1.d) states "A description of systems, structures and components determined to be safety class or safety significant will be developed based on the results of the hazard and accident analysis. This will include identification of the support systems, functional requirements, performance criteria necessary to provide reasonable assurance that the functional requirementswill be met, and identificationorassumptions needing Technical Safety Requirement coverage." As such, there was no criteria in the SARUP analyses for demonstrating that the probability of a system not performing its safety function is incredible (less than 1E-6).
c.
The operatar response to motor load indicator changes is described in the various cascade l
accident scenarios in SARUP Section 4.3.2.1. This section is the appropriate place for this l
information.
l d.
The motor load indicators provide a diagnostic tool for evaluating cascade performance and l
for detectinganomalous conditions. The motor load indicators are credited with providing - l informationto the operator so that an accident can be prevented. However, the motor load l
indicators are not credited in the scenarios with preventing or mitigating the consequences l
of any accident that could exceed the offsite EGs. As such, they do not satisfy the Q l
classification criteria and are appropriately classified as AQ.
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t SAR,UP Q&;R - PGDP/ PORTS May 10,1999 SARUP Revision:
No revision required.
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SAR,UP Q&R - PGDP/ PORTS -
May 10,1999 l~
Chapter 3 - Q22 (NRC 6/1/98 Letter)
PGDP/ PORTS - 63.15/3.8.5.1 a.
The analysis should provide more information and numerical values on the intermediate calculations supporting the conclusions of adequate temperature control and cylinder ullage space. This additional information should show the enthalpy calculations and assumed volumes of materials.
b.
There should be an explanation for the use of high pressure steam (>250 F/15 psig) that exceeds the pressure limit settings, and the reasons for not using a more passive system (steam < 250 F/15 psig, or even steam with conditions below the zero ullage temperature of the cylinder) included. The text should also clarify the actual steam pressures used in the calculations (60 or 100 psig) and ifintermediatepressures(say, in the 15-100 or 15-60 psig ranges) represent a greater potential hazard because of a longer time period (for heating) prior to reaching the autoclave pressure limit of 15 psig.
A probability analysis should be presented to support the conclusion of meeting its safety c.
function requirement.
d.
The text should clarify (by calculation) that a cylinder failure event does not result in excessive pressures and leakage from the autoclave, due to the cylinder's pressure and hydrolysis reactions.
e.
The reliabilityof the pressure relieflines should be based upon probabilitycalculations,and numerical values provided.
f.
As noted in the text, the loss of power operability of the isolation valves and positive indications of position need to be established.
Response
1
-a.
The analysis took into account the various cylinders heated including their ullage space and l
volume of material. The analysis provides the enthalpy calculations and other intermediate j
calculationsto support the conclusion that this system will accomplish its safety function.
l This analysis is available for review at the site or at USEC headquarters.
l b.
The SARUP Chapter 4, Accident Analysis, identifies the basis for the assumptions l
j regarding the steam supply. The steam is supplied by the site steam generating station l
which produces steam at greater than 100 psig and distributesit for use throughout the site.
l Pressure reducing stations are provided dependent on the use of the steam, such as to limit l
the steam pressure supplied to the autoclaves. As noted in this section, the calculations l
assumed a steam pressure of 100 psig. Initiating events at intermediate steam pressures l
would be bounded by the event analyzed. The SARUP Accident Analysis,Section 43.2.2.2 l
' describes the accident sequence in additional detail.
l c.
A numericalanalysis was not performed to demonstrate that the system would perform its safety function at any particular failure frequency. The capability of SSCs to perform their
- safety function was determined in the SARUP based on engineering analyses, engineering
. judgement,and plant operating history (supplemented in some cases with qualitative fault tree analyses). This process identified the SSC quality and operability requirements to provide adequate assurance that the SSC could be expected to perform its safety function.
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SARUP Q&R - PGDP/ PORTS May 10,1999 The process used in the SARUP is consistentwith the approach described in Section 1.d of l
the Plan of Action and Schedule for Compliance Plan issue 2.
d.
This issue is addressed in SARUP Chapter 4, Accident Analysis, Section 43.2.2.14. The l
l l
calculationregardingpressure increase is available at the site or at USEC headquarters for l
l review.
l (PORTS only) A numerical analysis was not performed to demonstrate that the system l
e.
would perform its safety function at any particular failure frequency. The capability of l J
SSCs to perform their safety function was determined in the SARUP based on engineering 'l l
analyses,engineeringjudgement,and plant operating history (supplemented in some cases l
with qualitative fault tree analyses). This process identified the SSC quality and operability l
requirementsto provide adequate assurance that the SSC could be expected to perform its j
safety function. The process use in SARUP is consistent with the approach described in l
1 Section 1.d of the Plan of Action and Schedule for Compliance Plan issue 2.
l 1
f.
(PORTS only) USEC agrees; that is why the description requires these functions. These l
issues are addressed in Compliance Plan, Issue 3.
l SARUP Revision:
No revision required.
l l
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SARUP Q&R - PGDP/ PORTS May 10,1999 Chapter 4 - Q10 (NRC 6/1/98 letter)
PGDP/ PORTS - Chapter 4 General The text uses a lot of different bases for its analyses. However, it appears that many of these correspond to normal operating conditions or bound conditions only 70-80% of the time, and do not represent "high" set points (i.e., the situation prior to a controller activation); potential examples include the withdrawal accumulators and the autoclave condensate systems. It is recommended that reasonably conservative, bounding parameters are used for the analyses, and that the corresponding text explains the basis for the conservatism.
Response: -
The analysis methodology described in SARUP Section 4.3.2 is inherently conservative. Based on the processes analyzed and the potential initiating events, reasonable, bounding assumptions were made. Also, throughout the analysis, conservative techniques were used to ensure a bounding analysis.
The corresponding text includes those conservatisms and provides a basis where applicable. Note that some of the bases for conservative parameters are described in the methodology and some are described in the scenario descriptions.
In a few instances, possible nonconservatisms may exist. However, these have been previously identified and submitted with the SARUP submittal.
SARUP Revision:
No revision required.
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- SAR,UP Q&R - PGDP/ PORTS -
May 10,1999 Chapter 4 - Q15 (NRC 6/1/98 letter) -
PGDP/ PORTS - 6 4.3.2.1.4 This is listed as an AE event - numericaljustification should be provided, a.
- b. '
No description of the scenario is provided - such a description should be included, along with a schematic / diagram, c,.
This event is stated to be the most limiting primary system failure for the AE category, but no numerical estimates are given. At a minimum, source terms should be quantified for this scenario.
d.
The scenario should estimate the impact of inleakage, and demonstrate that its effect is relatively small.
e.
The text states the primary concern as controllingthe release, yet it only mentions building holdup and evacuation (see and flee). Other control mechanisms should be mentioned and discussed, such as compressor tripping, cell isolation, valve closure, etc.
Response
There have been limited UF releases during the history of the GDPs (releases beyond off-a.
6 normal operational events that had the potential to impact workers outside the immediate area). Historically,none of the releases experienced from the cascade have exceeded 1,000 pounds. At releases ofless than 1,000 pounds, no effects to the general public offsite would be expected. The AE classification _ was a qualitative engineering judgement of the probability of a passive equipment failure resulting in a release of UF. that would potentiallyaffect facilities outside the release area or have a potential of challenging the AE EGs.
b.
The scenario description encompasses the potential for passive equipment failures to result in a limited release of UF and thus covers a range of potential release scenarios. The
)
evaluation determined that such releases would be bounded by the AE B-stream block valve closure event. The source term would be less than 11,700 lbs at 130 lbs/sec and would have no offsite impact and would require only building holdup and evacuation to maintain exposuresto onsite personnel within EGs. Individual source terms were not calculated for each possible scenario.
c.
The Plan for Achieving Compliance with NRC Regulations at the Paducah/Portsmouth Gaseous Diffusion Plant (Compliance Plan), Issue 2, Update the ApplicationSafetyAnalysis -
Report, specifies that the SARUP shall be developed consistent with the intent of DOE-STD-3009-94, Preparation Guidefor U.S. Department of Energy Nonreactor Nuclear Facility Safety Analysis Reports. This Standard specifies that the hazard and accident analysis will be primarily a qualitative assessment with the aim to "... produce a well reasoned and clear assessment of facility hazards and their associated controls." 'The Standaid further states that it "..does not present an expectation of or requirement for probabilistic/ quantitative risk assessment." The Standard specifies that representative
]
accidents are examined only to the extent that they are not bounded by the other accidents.
(Refer to Chapter 3 of the Standard).
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SARUP Q&R - PGDP/ PORTS May 10,1999 1
Consistentwith this Standard,the SARUP accident analysis utilizes qualitative analysis to determine accident frequency category assignments and provides source terms for those accidents which are considered bounding.. SARUP provides the link from the bounded representative accidents to the respective bounding accidents, as is the case with this scenario. No additional information is required.
i d.
The impact ofinleakage is to displace UF. with atmospheric air until the pressure equalizes.
At that point, some minimal outgassing of UF. and reaction products of the UF./ moisture
)
in the air reaction could occur. Operatingexperience has shown that this is of concern only for personnel working in the immediate area in sealing the containment breach; this can l
normally be accomplished simply by covering openings with plastic. Due to the normal l
building ventilation rates, there are no detectable concentrations of uranium or IIF outside of the area immediatelyaround the equipment breach. Once the breach is adequately sealed, the equipment is evacuated of UF. and purged so that maintenance can take place. In view of the above, there was no attempt made to calculate a source term for inleakage events.
e.
The next to last paragraph in the " Scenario Description" identifies that the same controls credited for the AE event,"B-stream Block Valve Closure" would be utilized to terminate the release as part of the overall operationalresponse to minimize impacts to personnel and the operation.
SARUP Revision:
No revision required.
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SARUP Q&R-PGDP/ PORTS May 10,1999 1'
l Chapter 4 - Q23 (page 16, NRC 6/1/98 letter)
PGDP/ PORTS - s 4.3.2.2.3 Releases of Solid / Gaseous UF. to Atmosphere His is identified as an AE event - a calculational or a historical basis for probabilities a.
should be used tojustify this designation.
b.
He source term analysis mentions 63 pounds of hexafluoride vapor. It states there is sufficient sensible heat to vaporize another 700 lbs of hexafluoride: however, it states that the heat is lost through the metal cylinder wall even though the solid UF. has a low
- thermal conductivity (i.e., low heat transfer). The apparent contradiction should be verified, as it would appear that a significant fraction of the 700 lbs should be included in the source term analysis.
The source term calculation for the cylinder at ambient conditions should explain the c.
calculation; in particular, the HF value seems low.
d.
The text indicates no dispersion analyses were performed for this event. Thus, how can it be stated that EG's are satisfied. Consequently, the text should state the consequence of the release for the worker and clearly show that consequences would not be exceeded at the closest location of public access.
Response
No numerical analysis was developed to quantify the frequency occurrence for a physical a.
integrityfailure(e.g.,valvefailure)involvingacylindercontainingsolidifiedUF Asnoted in the response provided for Chapter 4 Question 1 (NRC 6/1/98 letter), numerical estimates were not performed tojustify the frequency bin categorization of the evaluated events.
SARUP did utilize documented qualitative guidelines for categorizing events. These guidelines are available for review in support documentation located at each plant site.
b.
Although the system contains enough heat to create about 700 lbs of additional UF vapor at a pressure above one atmospheie, the majority of the heat will be lost to the atmosphere through the cylinder walls instead of subliming UF inside the cylinder. Design analysis calculationsthat provide the details associated with this source-term analysis are available for review at each plant site and at USEC headquarters.
Source-term calculations were performed to identify the potential release associated with c.
a valve failure on a 48G cylinder containing a nominal heel of 50 lb of UF. at ambient conditions of 90*F and 60% relative humidity. The amount of material released to the atmosphere in these calculations was related to the molecular weight of the particular material (i.e., UF., HF, etc.) and the ratio of the partial pressure of the material in the l
cylinder to the total pressure in the cylinder. These calculations are available for review at each plant site and at USEC headquarters.
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SARUP Q&R - PGDP/ PORTS May 10,1999 d.
The source-term analysis indicates that the maximum source-term associated with this event would be limited to the initial vapor content of a filled cylinder at the triple point temperature of 147.3'F (i.e.,63 lbs of UF. vapor). A cylinder at this temperature would have to be located at the cool-down yards which are located about 1000 meters from the site boundary at either site. Due to the small size of the potentialrelease and the distance to the site boundary,engineeringjudgment was used to state the consequencesof the event would j
be below the off-site exposure guidelines for an AE event.
As stated in the consequence analysis presented in the scenario, workers in the immediate area of the release could be exposed to significant uranium dose and/or HF exposure.
However,once a UF. release is detected by either sight (i.e. " white smoke" generated by the reaction of UF. vapor and atmospheric moisture)or odor HF (a reaction product of UF and moisture), on-site workers will evacuate the affected area in accordance with the plants'see j
and flee policy.
SARUP Revision:
1 No revision is required.
l l
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.s l'
r GDP 99-0081 STATUS OF RESPONSES TO Page 1 of 2 NRC QUESTIONS / COMMENTS ON SARUP 1.
2/5/98 NRC Ouestions i
Letter from Robert C. Pierson (NRC) to Mr. James H. Miller (USEC), "Paducah Certificate Amendment Request - Update of the Application Safety Analysis Report-(TAC NO. L32043)," dated February 5,1998.
Submitted 2/27/98:
Ql,Q2,Q3,Q4 Working:
None 2.
2/25/98 NRC Ouestions Letter from Charles Cox (NRC) to Mr. James H. Miller (USEC), "Paducah and Portsmouth Certificate Amendment Requests-Update of the Application Safety Analysis Reports (TAC Nos. L32043 & L32044)," dated February 25,1998.
Submitted 3/27/98:
Q4,Q8,Q10,Q11,Q12,Ql3,Q14,Ql5,Q19 Submitted 4/21/98:
Q1,Q2,Q3,Q5,Q6,Q7,Q9,Q16,Q18 Submitted 5/1/98:
Q17 Working:
None 3.
6/1/98 NRC Ouestions Letter from Charles Cox (NRC) to Mr. James H. Miller (USEC), "Paducah and Portsmouth Certificate Amendment Requests-Update of the Application Safety Analysis Reports (TAC Nos. L32044 & L32043)," dated June 1,1998.
Submitted 7/20/98:
Ch 2: Q1 Ch 3: Q4(a, f), Q5, Q6(a, g), Q7(a, d), Q8, Q9, Ql1(a, b),
Q12, Ql6(a, b), Ql7(a, b), Ql 8(a, b), Q22(c),
Q24(a, g)
Ch 4: Q2,QS Revised 10/5/98:
Ch 3: Q8 Submitted 4/19/99:
Ch 3: Ql-Q3, Q23, Q25, Q26, Q28-Q31, Q33-Q35 Ch4: Ql,Q3,Q6,Q8,Q9,Q11 Submitted 5/10/99:
Ch 3: Q11(c-0, Ql6(c-f),17(c d),18(c.d),Q22(a,b,d-f)
Ch 4: Q10,Q15,Q23, Working (8/31/99 Forecast): Ch 3: Q4(b-e,g), Q6(b-f, h), Q7(b, c), Q l 0, Q13, Q14, Q l 5, Q19-Q21, Q24(b-f), Q27, Q32, Q37 Ch 4: Q4, Q7, Q12-Ql 4, Q16-Q22, Q24, Q25-Q40
r GDP 99-0081 STATUS OF RESPONSES TO Page 2 of 2 NRC QUESTIONS / COMMENTS ON SARUP 4.
7/9/98 NRC Ouestions Letter from Charles Cox (NRC) to Mr. James H. Miller (USEC), "Paducah and Portsmouth Certificate Amendment Requests-Update of the Application Safety Analysis Reports (TAC Nos. L32044 & L32043)," dated July 9,1998.
Working (8/31/99 Forecast): Ch 1: Q1 Ch 3: Ql,Q2 Ch 4: Q1,Q2 TSR: Q1 - Q130 5.
7/14/98 NRC Ouestions Letter from Charles Cox (NRC) to Mr. James H. Miller (USEC), "Paducah and Portsmouth Certificate Amendment Requests-Update of the Application Safety Analysis Reports (TAC Nos. L32044 & L32043)," dated July 14,1998.
Submitted 11/10/98:
Q1 - Q15 Working:
. None j
k i
u