ML20206B969
| ML20206B969 | |
| Person / Time | |
|---|---|
| Site: | Portsmouth Gaseous Diffusion Plant, Paducah Gaseous Diffusion Plant |
| Issue date: | 04/19/1999 |
| 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-99-0067, GDP-99-67, TAC-L32043, TAC-L32044, NUDOCS 9904300137 | |
| Download: ML20206B969 (24) | |
Text
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GDP 99-0067 DRMA
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FILE Dr. Carl J. Paperiello Director, Office of Nuclear Material Safety and Safeguards Attention: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Paducah Gaseous Diffusion Plant (PGDP)
Portsmouth Gaseous Diffusion Plant (PORTS)
Docket Nos. 70-7001 & 70-7002 Response to NRC Request for AdditionalInformation - Safety Analysis Report Update (TAC Nos. L32043 and L32044)
Dear Dr. Paperiello:
By letter dated June 1,1998 (see the references), the Nuclear Regulatory Commission (NRC)
)
forwarded to the United States Enrichment Corporation (USEC) vari <.u 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.
J If you have any questions on USEC's responses, please call me at (301) 564-3250 or Steve Routh b
at (301) 564-3251. There are no new commitments contained in this submittal.
Sincerely, 1
S. 4.
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Steven A.Toelle Nuclear Regulatory Assurance and Policy Manager 9904300137 990419 PDR ADOCK 07007001 C
PDR 6903 Rockledge Drive, Bethesda, MD 20817-1818 l
Telephone 301-564-3200 Fax 301-564-3201 http://www.usec.com Offices in Livermore, CA Paducah, KY Portsmouth, OH Washington, DC ffjj pg jggg
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.J SARUP Q&R - PGDP/ PORTS April 19,1999 Chapter 4 - Q9 (NRC 6/1/98 Letter)
PGDP/ PORTS - Frequency, Probability, and Operating Time The SARUPs group and compare the events based upon frequency, i.e. on a per year basis or with a return year period. It is not clear if the SARUP's consistently factor the number of components into the analyses. However, nuclear industry practice routinely uses probability over the operating period of the facility, which includes the effects of the number of components /SSC's and the operating time of the facility, These increase the probability to a larger value than the stated frequency. For example, an individual component might have a failure rate of IE-5/yr, but if the number of these components is 2,000 (in operation) over an operating time period of 10 years, then the probability of failure is 0.2, and this becomes an anticipated event instead of an evaluation basis event.
Response
As stated in response to Chapter 4 - Qi (NRC 6/1/98 Letter), the SARUP accident analysis utilizes qualitative analysis to determine accident frequency category assignments. This is consistent with Compliance Plan Issue 2 and DOE-STD-3009-94, " Preparation Guide for U. S. Department of Energy Nonreactor Nuclear Facility Safety Analysis Reports," upon which the SARUP methodology is based.
Qualitatively, the accident frequency categorizations do consider the number of components in the plants, as well as other factors such as operating experience. The qualitative frequency categorizations are, however, not based on a projected lifetime of the plant. The frequency bin (i.e., AE, EBE) ranges are based on annual probability, which is also consistent with DOE-STD-3009-94.
SARUP Revision:
No revision required.
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SARUP Q&R - PGDP/ PORTS April 19,1999 o
Chapter 4 - Q11 (NRC 6/1/98 Letter)
PGDP/ PORTS - Specific Comments In Sections 4.2,4.3, and elsewhere, relief valves and rupture disks are mentioned as safety devices for avoiding over pressurization of vessels and components. However, no mention is made of the environment of the relief device itself, i.e., does it relieve through a filter to a stack, does it exhaust into the operating area near workers, etc.? The text should discuss the relief device location and the potential effects of its activation upon potential onsite and offsite accidents.
Response
Where the accident analysis identifies the actuation of a relief system as part of the accident scenario, the location of the vent path is taken into account in assessing the consequences. Where the accident analysis does not identify the actuation of the relief device in any of the accident scenarios, there is no reason to discuss the relief path.
SARUP Revision:
No revision required.
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- GDP 99-0067 STATUS OF RESPONSES TO Page 1 of 2 NRC QUESTIONS / COMMENTS ON SARUP 1.
2/5/98 NRC Ouestions 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, Q13, Q14, Q15, Q19 Submitted 4/21/98:
Ql,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 Partsmouth 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 Cn 3: Q4(a, 0, QS, Q6(a, g), Q7(a, d), Q8, Q9, Qll(a, b),
Q12, Q16(a, b), Q17(a, b), Q18(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 Ch 4: Q1,Q3,Q6,Q8,Q9,Ql1 Working (8/31/99 Forecast):
Ch 3: Q4(b-e), Q6(b-f, h), Q7(b, c), Q10, Ql1(c-0, Q13, Q14, Q15, Q16(c-0, Q17(c, d), Q18(c, d), Q19-Q21, Q22(a, b, d-0, Q24(b-0, Q27, Q32, Q37 Ch 4: Q4, Q7, Q10, Q12-Q40
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GDP 99-0067 STATUS OF RESPONSES TO Page 2 of 2 NRC QUESTIONS / COMMENTS ON SARUP 4.
'T/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 Ch3: Q1,Q2 Ch 4: Q1,Q2 TSR: Q1 - Q130 5.
2/14/98 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 i
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Dr. Carl J. Paperiello April 19,1999 GDP 99-0067, 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 -Q1,2,3,23,25,26,28-31,33-35; Chapter 4 - Q1, 3,6,8,9,11 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 Mr. Robert C. Pierson, NRyHQ cc:
NRC Region III Office V NRC Resident Inspector - PGDP NRC Resident Inspector-PORTS Mr. Randall M. DeVault (DOE)
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1 GDP 99-0067 Responses to Chapter 3 -Q1,2,3,23,25,26,28-31,33-35; Chapter 4 - Ql,3,6,8,9,11 from the June 1,1998 NRC Request for Additienal Information -
Safety Analysis Report Update (TAC Nos. L32043 and L32044) i
1 SARUP Q&R - PGDP/ PORTS April 19,1999 Chapter 3 - Q1 (NRC 6/1/98 Letter)
PCD' MORTS - Chapter 3 General Provide more detail on how the structures, systems, and components (SSCs) meet their functional requirements. If the SSCs do not meet that requirement by fail safe mec;tanism, i.e.; battery back-up, air reservoirs, identify the surveillance used to ensure that the safety system can meet that functional requirement. If the SSC has a Technical Safety Requirement (TSR) that surveillance should be in tne TSR.
Response
The information provided in the " Functional Requirements" and " System Evaluation" subsections of SARUP Section 3.8 (PORTS)/3.15 (PGDP) is consistent with the content and level-of-detail included in the DOE SAR Upgrade (Chapter 4 of KY/EM-174 and POEF-LMES-89). Note also that facility and process descriptions are currently provided in the other sections of Application SAR Chapter 3 (i.e.,
i Sections 3.1 through 3.14 for PGDP, and Sections 3.1 through 3.7 for PORTS). Based on this information, it is concluded that an adequate level of detail is provided to describe how SSCs meet their functional requirements.
For those SSCs described in SARUP Section 3.8 (PORTS)/3.15 (PGDP) that are not fail-safe, support systems (e.g., air, electrical power) that are necessary to accomplish the required safety functions
)
are included in the system classification boundary as identified in SARUP Tables 3.8-1 through 3.8-3 (PORTS)/3.15-1 through 3.15-3 (PGDP). Plant procedures identify the actions necessary to confirm the functioning of required support systems.
j As descrfbed in USEC Letter GDP 99-0M2 dated February 26,1999, the SARUP submittals are being revised to adopt the current TSRs that are included in Volume 4 of USEC's Certification Applications (USEC-01 and USEC-02). NRC questions on the scope of sur veillances included in individual sections of the current TSRs will be addressed as they are provided to USEC.
SARUP Revision:
No revision required.
i c.
SARUP Q&R - PGDP/ PORTS April 19,1999 Chapter.2 - Q2 (NRC 6/1/98 Letter)
PGDP/ PORTS - Chapter 3 General For those SSCs that hree identified exceptions in their ability to perform their required safety function, provide further justification that would explain why those SSCs should be considered
" operable" (as defined in the TSRs).
Response
The subject of this question was discussed in detail at the May 28,1998 meeting between NRC and USEC held at the NRC Headquarters in Rockville, Maryland. At the meeting, the results of the USEC evaluation were discussed which concluded that the plant SSCs were operable.
SARUP Revision:
No revision required.
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SARUP Q&R - PGDP/ PORTS April 19,1999 Chapter 3 - Q3 (NRC 6/1/98 Letter)
PGDP/ PORTS - Chapter 3 Specific Comments On page 3.8-1/3.15-1: the SARUP should clarify the Q/AQ SSC designstion to include anticipated events (AE) in addition to evaluation basis events (EBE) meeting the evaluation guidelines.
Response
The consequences of anticipated events are included in the criteria for the classification of AQ structures, systems, and components. See SARUP Table 4.2-2 and the discussion in SARUP Section 4.2.2.
SARUP Revision:
i No revision required.
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1 SARUP Q&R - PGDP/ PORTS April 19,1999 Chapter 3 - Q23 (NRC 6/1/98 letter)
PORTS - 13.8.5.2 Remote Transfer Isolation System The calculations supporting the safety function analysis should be provided, a.
b.
As noted in the text, continued operability of the pigtail /line isolation valves upon loss of air power needs to be established, c.
The text mentions "other deficiencies" - these should be described.
Response
a.~
The calculations supporting the safety functional analysis are described in SARUP Section 4.3.2.2.10. The results of valve actuation times and associated calculations verifying that the valves will close in 30 seconds after operator actuation of the system are available onsite or at USEC headquarters for review.
' b.'
USEC agrees; that is why the description required this function and referenced Compliance Plan Issue 3. _ Compliance Plan Issue 3 requires the deficiency to be corrected and establishes a justification for continued operation (JCO) to ensure adequate safety until the modifications can be completed.
c.
Compliance Plan Issi;e 3 addresses a number of actions to either restore the autoclaves to l
their original design configuration ~(e.g., restore the autoclave head /shell sealing surfaces) or to provide operational improvements to enhance safety and operability (e.g., inner and outer loop containment valve testing, upgrade of internal pressure transmitters, provide operational alarms to alert operators of potential upset conditions, modify condensate i
amoval systems, etc.). In most cases, these actions will reduce the number of safety system actuations and/or potential for failure of surveillances. The Compliance Plan JCO provides a description of the compensatory actions to be taken to assure adequate safety until the scheduled actions are completed.
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SARUP Q&R - PGDP/ PORTS April 19,1999 l
Chapter 3 - Q25 (NRC 6/1/98 Letter)
PGDP/ PORTS - 53.8.5.5/3.15.15.5 Autoclave High Condensate Level Cutoff System See question 8.
Response
See the response to Chapter 3 - Q8 (NRC 6/1/98 Letter) which was submitted to the NRC by USEC Letter GDP 98-0199 dated October 5,1998.
SARUP Revision:
No.evision required.
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SARUP Q&R - PGDP/ PORTS April 19,1999 Chapter 3 - Q26 (NRC 6/1/98 Letter)
PGDP/ PORTS - 53.8.5.6 UF Cylinder High Pressure Steam Cutoff System Sec question 9.
Response
See the response to Chapter 3 - Q9 (NRC 6/1/98 Letter) which was submitted to the NRC in USEC Letter GDP 93-0140 dated July 20,1998.
SARUP Revision:
No revision required.
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SARUP Q&R - PGDP/ PORTS April 19,1999 Chapter 3 - Q28 (NRC 6/1/98 Letter)
PGDP/ PORTS - 13.8.5.8 Autoclave locking Ring Interlock System See question 11.
Response
See the response to Chapter 3 - Q11 (NRC 6/1/98 Lener) which was submitted to the NRC in USEC Letter GDP 98-0140 dated July 20,1998.
SARUP Revisiou:
i No revision required.
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SARUP Q&R - PGDP/ PORTS April 19,1999 L
Chapter 3 - Q29 (NRC 6/1/98 Letter)
PGDP/ PORTS - 53.8.6.1/3.15.6.1 The cylinders are identified as either Q or AQ safety equipment, depending on the amount of hexafluoride they contain, with 500 lbs as the maximum quantity for an AQ cylinder (i.e., the 500 lb quantity provides a uranium uptake of 30 mg [the limit] at the site boundary). This calculation should be provided and discussed.
Response
l Threshold consequence analyses evaluated the consequences associated with a liquid UF, release originating from an open cylinder valve in the 6 o' clock position. This threshold analysis showed taat approximately 3000 pounds of liquid UF. would have to be released at a rate of 14.7 lbs/s to exceed 30 l
mg at 1400 meters under F (stability class) 1 (w:ad speed in m/s) meteorological conditions. Based on this l
threthold analysis, UF. cylinders that have the capacity to hold more than 500 lbs of UF. were conservatively classified as Q systems while smaller cylinders were classified as AQ systems. The threshold consequence analyses are available onsite or at USEC headquarters for review.
SARUP Revision:
l No revision required.
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-2 SARUP Q&R - PGDP/ PORTS April 19,1999.
Chr.pter 3 - Q30 (NRC 6/1/98 Letter)
PGDP/ PORTS - 93.8.6.2/3.15.6.2 Liquid UF cranes and handling equipment are described. Quantitative values should be provided for earthquake and wind loading capeities of the components as compared to the limi s. Also, the "small additional movement" due to swinging when the crane stops should be quantified and the crane path should oc verified for lack of an effect from a swinging load. The basis for testing should be provided (i.e., a probability / risk caleM n, manufacturers recommendation, code).
Finally, as noted in the text, additional information should be provided on the seismic response of the railcars (PORTS).
Response
Natural phenomena' hazard analyses for the liquid UF. handling cranes and equipment are documented in various reports prepared for the SARUP. These reports evaluate the capacities of the equipment compared to the limits of defined evaluation basis natural phenomena events (e.g., a 0.15g earthquake or 70 mph straight wind). Although the specifics of these evaluations are not discussed in the
. identified SARUP sections, the results are summarized to illustrate that the liquid UF handling cranes and equipment can perform their required safety functions during evaluation basis events. The originating reports are available onsite or at USEC headquarters for review.
The liquid UF cylinder handling cranes are designed so that when the controls are released, only small compensatory movements occur. These small movements are due to momentum associated with stopping the drive mechanism and applying the b' rakes. The emergency stop function of the liquid UF.
cylinder handling cranes is designed to minimize load swing associated with stopping the crane. The l'
maximum amount of allowable drift associated with stopping the cranes in this manner is specified by applicable industry standards (see SAR/SARUP Chapter 1, Appendix A) and controlled by applicable procedures.
Thei applicable standards for inspection and testing of liquid UF cylinder handling cranes are L
identified in SAR/SARUP Chap:er 1, Appendix A.
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The seismic response of the rail cars at PORTS was addressed in USEC letter GDP 98-0251 dated November 20,1998.
SARUP Revision:
No revision required.
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L SARUP Q&R - PGDP/ PORTS '
April 19,1999 Chapter 3 - Q31 (NRC 6/1/98 Letter)
]
1 PGDP/ PORTS - 53.15.6.4/3.8.6.4 Cylinder Weighing System l
a.
The discussion on the safety functions, functional requirements, and system evaluation should be more quantitative, mentioning weights, accuracies, and demonstrating how the accuracies are adequate to avoid overfilled cylinders.
I l.
h.
Since an overfilled cylinder could rupture once heated in an autoclave, and such a ruptured
)
l-cylinder would have offsite effects, the text should explain and discuss why this system has l
an AQ instead of a Q desigaation.
)
1
. Response:
l The functional requirements for the cylinder. weighing system regarding accuracy,.
a.
calibration and other issues are contained in the Fundamental Nuclear Materials Control Program (FNMCP) in Volume 3 of the Certification Applications (USEC-01 and USEC-02). The FNMCP requirements for control and accountability of nuclear materials are more stringent thvi those required for preventing overfilling of a cylinder by approximately an order of magnitude. Consequently, no further detail is needed in SARUP Section 3.15.6.4/3.8.6.4 since the controlling document is the FNMCP.
l b.
The accider c a i ' sis shows that a rupture of a cylinder inside an autoclave would not result _in exct,d4 the offsite Evaluation Guidelines with the essential control of the autoclave primary containment system. 'Ihus, the cylinder weighing system is properly j
classified as AQ.
L SARUP Revision:
l No revision required.
i SARUP Q&R - PGDP/ PORTS April 19,1999 1
Chapter 3 - Q33 (NRC 6/1/98 Letter)
PGDP/ PORTS - 53.8.7.4/3.15.7.5 The text should explain why the Public Warning System is categorized as an AQ instead of a Q system.
Response
The Public Warning System does not satisfy any of the Q or AQ category selection criteria stated in SARUP Section 4.2.2. This notwithstanding, the current AQ classification of the system as identified in Application SAR Section 3.15.2.15/3.8.2.17 has been retained in the SARUP. No additional information is required in SARUP Section 3.15/3.8 as to why the Public Warning System is not classified as a Q system.
SARUP Revision:
No revision required.
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SARUP Q&R - PGDP/ PORTS April 19,1999 Chapter 3 - Q34 (NRC 6/1/98 Letter)
PGDP/ PORTS - $3.8.9.2/3.15.9.2 Building Crancs a.
Numerical values and results from the analysis should be provided, including frequency numbers for movements and movements over parts of the cascades, b.
Frequency numbers from industry should be used to demonstrate functionality for holding heavy loads during no power and activation events.
Response
- a.
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 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.
)
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 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.
l SARUP Revision:
l No revision required.
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i SARUP Q&R - PGDP/ PORTS April 19,1999 Chapter 3 - Q35 (NRC 6/1/98 Letter)
PGDP/ PORTS - Tables 3.8-1/3.15-1 Tables 3.8-1/3.15-1 provides the boundary definitions for Q SSCs. As noted in the previous comments, consideration should be given to including additional items on the Q list, such as portions of the fire systems, building confinement, ammeters / indicators, and block valves. Also, clarification should be provided for the exceptions listed in the table (primarily due to loss of power / air) as not all of these are captured in the text.
Response
Table 3.15-1/3.8-1 defines the Q structures, systems, and components based on the criteria presented in SARUP Section 4.2. Where there are exceptions identified in the table that are not discussed in the text, the tables provide adequate information when read in conjunction with the section as a whole.
SARUP Revision:
l No revision required.
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~ g SARUP Q&R - PGDP/ PORTS April 19,1999 Chapter 4 - Q1 (NRC 6/1/98 Letter)
PGDP/ PORTS - Qualitative Arguments Instead of Quantitative Analyses
'Ihe accident scenatics include a significant amount of qualitative discussion in the text, but with few quantitative numbers to support some of the conclusions, such as frequencies and bounding source terms. This contributes to uneven analysis in some areas. The SARUP should include quantitative values for as many of the scenarios as possible, particularly for the source terms and probabilities, and for the determination of bounding accidents. Use of quantitative analysis are a benefit to be able to determine if adequate safety is ensured and a benefit for funire 76.68 change reviews for unreviewed safety questions.
Response
Compliance Plan Issue 2 specifies that the SARUP shall be developed consistent with the intent of DOE-STD-3009-94, " Preparation Guide for 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 cont.ols." The Standard 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 j
Chapter 3 of the Standard).
l Consistent with this Standard, the SARUP accident analysis utilizes qualitative analysis to I
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. USEC does not believe that the analysis is uneven, rather the analysis is fully consistent with the DOE Standard and Compliance Plan Issue 2. Furthermore, the SARUP together e
with its supporting docum:nts provide an adequate basis from which to determine if adequate safety is ensured during future 10 CFR 76.68 change reviews for unreviewed safety questions. No additional
. analysis or documentation in SARUP is requited.
SARUP Revision:
No revision required.
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SARUP Q&R - PGDP/ PORTS April 19,1999 Chapter 4 - Q3 (NRC 6/1/98 Letter)
PGDP/ PORTS - Operator Action Requirements A significant number of the accident scenarios require operator notification, interpretation, and action for avoidance or mitigation of accidents. The SARUP's are not clear on the b'unan factors and time frames involved; some of the stated time periods seem optimistically shoa and it is not clear that the operator can be notified, and interpret and act upon the information, and the equipment operate (e.g., valve closure or compressor motor trip) in the needed time frames,
. particularly if the operator has multiple duties or if the event occurs during break or shift-changing times that might divert attention or otherwise distract the operator. The licensee should discuss human factors, training, conduct of operations, etc. in more detail, and explain the interactions between the different control locations (e.g., LCR, ACR, main control room, outside panel) and the time frames.
Response
The time frames for required operator actions were based on engineering judgement and operating experience. Application SAR Chapter 6 describes conduct of operations, training, and human factors as applied to plant operations. The required operator actions were taken into account in developing the required staffing levels _ While many perturbations could be postulated that might affect operator reaction times, the times chosen are reasonable. No detailed time study analyses need to be performed to justify the times chosen.
SARUP Revision:
No revision required.
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SARUP Q&R - PGDP/ PORTS April 19,1999 Chapter 4 - Q6 (NRC 6/1/98 latter)
PGDP/ PORTS - Historical Data and Evaluation Basis Events (EBE)
The text cites historical plant data and experiences in several parts of the text, including the use of this data and experience for EBE. It is not clear how events that have occurred several times over the 40 year plus operational history of the GDP's can constitute EBE's (i.e., less than one in 100 year occurrence). Also, events are placed into the EBE category using qualitative arguments instead of a numerical estimate. The SARUP's should clarify the bases for placement of events in the EBE category and use numerical estimates.
Response
i As noted in SARUP Sections 4.1 and 4.2, the assignment of initiating events to an AE or EBE category was done qualitatively based on engineering judgement. In the case of events assigned an EBE category that have occurred, the assignment is based on engineered and administrative controls that were I
implemented following the actual event. As noted in the response to Chapter 4 - Q1 (NRC 6/1/98 Letter),
i numerical estimates were not performed to justify the categorization of events.
SARUP Revision:
i No revision required.
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SARUP Q&R - PGDP/ PORTS April 19,1999
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Chapter 4 - Q8 (NRC 6/1/98 Letter)
PGDP/ PORTS - Chronology of Events Several of the accident scenarios rely upon prompt operator action, which may be neither realistic
. nor conservative. Consequently, the sequence and chronology of these events should be clarified.
. For example, while valve closure times are mentioned, it is not clear that the other, preceding time periods (undetected release time, detection / location time, notification time, operator comprehension of the event, and operator reaction time) are adequately considered. Also, the text refers to the local, area, and central control rooms, without an explanation of the inter-relationships and the human factor considerations; for example, an operator observing / monitoring just a few indicators / controls usually responds faster and. more correctly than an operator observing / monitoring many controls. Consideration should be given to the potential impacts of
~ shift turnover and break periods. ' A summary of the results from drills and training exercises may be useful for giving a lower bound for the operator time' periods.
Response
As discussed in the response to Chapter 4 - Q3 (NRC 6/1/98 Letter), the operator response times used in the SARUP are appropriate. While the SARUP analyses did not attempt to evaluate every possible variation of operator response time, the times selected accounted for operator location, assigmnents, and
' cognitive ability in a qualitative fashion. Application SAR Chapter 6 describes the operational means (i.e.,
conduct of operations) to deal with the issues of shift turnover, breaks, etc.
SARUP Revision:
' No revision required.
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