ML20205J229
| ML20205J229 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 04/02/1999 |
| From: | Wen P NRC (Affiliation Not Assigned) |
| To: | Carpenter C NRC (Affiliation Not Assigned) |
| References | |
| NUDOCS 9904090238 | |
| Download: ML20205J229 (24) | |
Text
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-4 UNITED STATES E 4 Tf ) j NUCLEAR REGULATORY COMMISSION
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. t WASHINGTON. D.C. 20555-4001
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April 2, 1999 MEMORANDUM TO: Cynthia A. Carpenter, Chief Generic issues, Environmental, Financial and Rulemaking Branch Division of Regulatory improvement Programs Office of Nuclear Reactor Regulation FROM:
Peter C. Wen, Project Manager [d C. !MM Generic issues, Environmental, Financial and Rulemaking Branch Division of Regulatory improvement Prograrns Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF MARCH 25,1999, MEETING WITH WESTINGHOUSE OWNERS GROUP (WOG) REGARDING WCAP-14986 WOG POST ACCIDENT SAMPLING SYSTEM On March 25,1999, a public meeting was held at the U.S. Nuclear Regulatory Commission's (NRC's) offices in Rockville, Maryland, between members of the Westinghouse Owners Group (WOG), Wolf Creek Nuclear Operating Corporation (WCNOC), and NRC staff. Attachment 1 lists attendees at the meeting and Attachment 2 contains a copy of the material presented at the meeting.
The purpose of the meeting was to discuss the NRC staff's comments on the WOG post accident sampling system (PASS) approach (Topical Report WCAP-14986, Rev 1, " Westinghouse Owners Group Post Accident Sampling System Requirert ts: A Technical Basis") which is currently under staff review. This document,if approve ( / the staff, would provide the technical basis for licensees to relax PASS commitments made in response to the Three Mile Island Action items specified in NUREG-0737. To facilitate the discussion, a list of issues was faxed to WOG March 15,1999, and placed in the NRC public document room (Accession Number 9903190191) before the meeting.
During the meeting, WOG representatives presented an overview of the technical basis for the proposed changes in PASS capabilities. Following this presentation, representatives of WOG and the NRC staff discussed each of the issues which were faxed to WOG before the meeting.
A summary of these discussions is included in Attachment 3. Due to tirre constraints, issues related to the site-specific application of the PASS topical by WCNOC were discussed in a teleconference k
held on March 29,1999. A summary of these discussions is also contained in Attachment 3.
The WOG presentation and discussion clarified many of the issues the NRC staff had on the
)
topical. The NRC staff willissue a request for additionalinformation where further documentation is needed to complete its review. WOG representatives emphasized the need g
to resolve open issues as soon as practicable because the lead plant (Wolf Creek) for applying q\\
the Topical needs to make modifications to its PASS due to computer Y2K problems if current commitments are not modified.
82 P
PDR 4
1 i
C. Carpenter A meeting with the Severe Accident Management Subcommittee of the Advisory Committee on Reactor Safeguards (ACRS) to discuss the WOG topical is scheduled for April 30,1999 and a meeting with the full ACRS committee is scheduled for the first week in May 1999.
Attachmerits: As stated cc w/atts: see next page DISTRIBUTION: See attached page ocument Name: g:\\pxq\\msm_ pass.wpd
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OFFICE PM:RGEB: DRIP HOLB DIPM (A)S,C-h NAME PWen:ayw 9cd JdBgk @ I TBergM[v d
DATE 04/ t /99 04/ [ /99 04&/9[l OFFICIAL OFFICE COPY i
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4 Westinghouse Owners Group cc:
Mr. Nicholas Liparulo, Manager Regulatory and Engineering Networks l
Westinghouse Electric Corporation l
Mail Stop ECE 4-15 P.O. Box 355 Pittsburgh, PA 15230-0355 i
Mr. Andrew Drake,' Project Manager l
Westinghouse Owners Group l
Westinghouse Electric Corporation
- Mail Stop ECE 5-16 l
P.O. Box 355 l
Pittsburgh, PA 15230-0355 Jack Bastin, Director Westinghouse Electric Corporation 11921 Rockville Pike, Suite 107 Rockville, MD 20852 l
l
- Mr. Hank Sepp, Manager l
Re9ulatory and Licensing Engineering Westinghouse Electric Corporation i
PO Box 355 l
Pittsburgh, 'PA 15230-0355 r
1 4
l i
'b Distribution: Mtg. Summary w/ WOG Re PASS lssues Dated Hard Coov iAW.Sj$i PUBLIC PGEB R/F OGC ACRS PWen RPalla JO'Brien LLois KParczewski KThomas EMail SCollins/RZimmerman BSheron WKane GHolaha:1/TCollins JWermiel EWeiss FOrr JStrosnider/RWessman W Bateman TSullivan DMatthews/SNewberry CCarpenter
- TBergman PBoehnert GTracy, EDO MMarkley i
NRC/WOG MEETING ON WOG PASS TOPICAL REPORT LIST OF ATTENDEES March 25,1999 NAME ORGANIZATION Tom Essig NRR/DIPM/HOLB James O'Brien NRR/DIPM/HOLB Bob Palla NRR/DSSA/SPSB Frank Orr NRR/DSSA/SRXB Warren Lyon NRR/DSSA/SRXB George Thomas NRR/DSSA/SRXB Paul Boehnert NRC/ACRS Kris Thomas NRR/DLPM/PD lil-2 Peter Wen NRR/ DRIP /RGEB Larry Walsh NAESCo Ken Vavrek WOG-Project Andrew Drake WOG-Project Bob Lutz Westinghouse Wayne Harrison STPNOC Dennis Boyd ANO Kud Cozens NEl Alan Nelson NEl Bob Bryan TVA Jack Stringfellow SNC Dale Lemnons WCNOC lerry Carrett WCNOC David Lounsbury PSE&G Ray Schneider ABB-CEOG Gordon Bischoff ABB-CEOG ATTACHMENT 1 1
1
Westinghouse Owners Group Relaxatlan of Post Accident Sampling System (PASS)
Requirements Bob Lutz Westinghouse / Westinghouse Owners Group March 25,1999 w
W@D WOG Relaxation of PASS Requirements i
5.
The regulatory intent of Post Accident Sampling is to support core damage assessment and the formulation of offsite protective action r~.ommendations 50.47(bX4) requires a standard emergency classification scherne, the bases v
of which would include facility system and caluent parameters...
50.47(bX9) requires adequate methods, systema, and equipment for assessing a radiological Emergency condition..
50.34(fX2Xviii) requires capability to prompdy obtain and analyze samples form reactor coolant and containment. materials to be analyzed and quantified include certain radionuclides that are indicators of the degree of core damage.. NOTE that 50.34(fX2Xviii) is not applicable to any currently operating reactors 0737 Criteria H.B3 requires a design and operational review of the radiological spect Nm analysis facilities to determine the capability to promptly quantia, certain radionuclides that are indicators of the degree of core damage..
W@D
=
ATTACHMENT 2
WOG Relaxation of PASS Requirements Regulatory latent for PASS (continued) e
. Regulatory Guide 1.97 provides a list of parameters to be monitored with th-intent detecting and quantifying fuel rod cladding and reactor coolant system breaches and to assess the potential for further clWienges
. GDC 64 requires that a means be provided to rnonitor the reactor containment atmosphere, spaces containing componcats for recirculation ofloss-of-coolant accident fluids, effluent discharge paths, and the plant environs WGDD 1
WOG Relaxation of PASS Requirements 3.
The applicable regulatory requirements and/or the latent of the arquirrments can be AND IS PRESENTLY met without a Post Accident Sampling
. Emergency Operating,:ocedure steps that could be executed after core damage are based on instrutnentation indications and do not depend on the results of post-core damage sample analysis Emergency Action Level classifications would be triggered based on instrumentation indications and do not depend on the result of anal, as of samples No Protective Action Recommendations would be rnade based instrumentation indicahons and a not depend on the results of analysis of samples Offsite dose projections would be rnade based on instrumentation indications / diagnosis of accident class and do not depend on the results of analyses of samples to estimate offsite radiation levels WGDE i
i 2
L WOG Relaxation of PASS Requirements 4
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'I RG1.97/NUREG-0737 Qualified Post Accident Sampling System would nhinclude:
2
. RCS boma within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />
. Containment l'ydrogen within _ hours
. cither on-line Monitors, or
. grab sampic
. Containment sump pH for brackish water plants without passive pH control WGDD WOG Relaxation of PASS Requirements l
s.
. Need ability to obtain samples forlong-term cleanup /rtcovery planning
. Containment atmosphere sample
. Containment sump sample
. RCS liquid sample W4DD 3
WOG Relaxation of PASS Requirements Proposed change in PASS regulatory requirements e
. Remove appropriate PASS reqmrements for timing and accuracy
. Maintain capability to obtain contamnx:nt atmosphere, sump and RCS samples for long-term c!canup/ recovery planning
. SER on WCAP-14986-P would allow licensee changes as appropriate:
.USAR
. Tech Spec
. E-Plan W4ED WOG Relaxation of PASS Requirements
. ~
= Reactor Coolant System Borva
. Retain requirement forpost-com damage RCS boron PASS sample
. Changing timing to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> after attaining a safe stable plant condition.
W4DD
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WOG Relaxation of PASS Requirements Reactor Coolant System Dissolved Gases / Dissolved Hydrogen
. Delete from required PASS capability in tenus of timing and accuracy of samples
. RCS gases samples are not required per EOPs/SAMGs to attain a safe stable plant condition
. Critical Safety Function monitoring (part of EOPs) relics on monitoring reactor vessel level instrn-ntntinn to assure that a safe stable plant condition has been achieved.
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. TSC guidance, on usmg reactor lead vent does not rely on RCS sample analysis for dissoh'ed gases l
1 WGDD WOG Relaxation of PASS Requirements e a y...,.,........m..
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. Reactor Coolant System Oxygen / Chlorides / pH
. Dc!cte from required PASS capability in terms of timing and accuracy of samples
. RCS samples are not required per EOPs/SAMGs to attain a safe stable plant condition
. RCS chemistry depends on accident sequence:
. With ECC recirculation, sump chemistry is controlling
. With RHR or SG cooling, the chemistry of any RCS makeup is well ktown
. Includes SGTR where chemistry secondary side wateris wellknown
. If any other source of water is introduced to the RCS, the t-quantity and chemistn should also be well known WGDD s
l i
l WOG Relaxation of PASS Requirements
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....,s
..y Reactor Coolant System and Containment Radionuclides
. Delete from required PASS capability in terms of timmg and accuracy I
ofsamples
. Radionuclide sampics are not required for any EOP, S AMG, or emergency planning activity expect for intentional releases
. CDA, EAL, PAR, Offsite Dsse Projection etc. all use fixed in-plan instrumentation as the primar, information based on timeliness and reliability
. For intentional releases samples may be used to validate PARS
. Based on current krowledge of fission product behavior, the NUREG-0737 assumptions on information from analysis of samples for radionuclides is not valid - more detail in revised WOG CD A report.
. Releases from fuel during core daraage for differerd species
. Deposition in the RCS and containment WGDD i
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WOG Relaxation of PASS Requirements t
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Containment Hydrogen
. Containment hydrogen can be determined from either On-Line
. Hydrogen Monitor (not part of PASS) or PASS samples
. Need one method to measure contamment hydrogen to support EOPs and SAMG
. Either method is acceptable (but only one is required) as long as the following criteria can be met:
. Accuracy of + or - 1% is adequate for EOP / S AMG needs
. Timing is within 30 minutes of the onset of core damage (e.g., core exit thermocouples greater than 1200 F)
)
. Repeat measurements can be made every 10 to 15 minutes l
WGDI;;
i 6
WOG Relaxation of PASS Requirements
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..... -......,..s.
= Containment Sump pH / Chlorides
. Delete from acquired PASS capability in terms of tinung and accuracy of samples, except brackish water sites with no passive pH control
. Containment sump sampics are not required per EOPs/SAMG to attain a safe stable plant condition
. Containment Sump chemistry depends on accident sequence:
. Containment sump chemistry depends on spray additive tank /
passive pH contro!
. For additional waterin containment sump, t!e chemistry of any added water can be diagno:,ed and estunated WGDD WOG Relaxation of PASS Requirements a..
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/,..,,e Containment Sump Boron
=
. Delete from iequired PASS capabiEty in terms of timing and accuracy of samples
. Containment sump samples an: not required per EOPs or S AMG to attain a safe stable plars condition
. Sources of water addition and boron content are conservatively set in design basis analyses
. For intentional water additions to the containment sump (S AMG), the chenustry of any added water can be diagnosed ard estimated WGDD 7
WOG Relaxation of PASS Requirements Cost savings rcJated to proposed change la PASS regulatory trquirements
. Cost of maintaining mnmtal and or automated equipment Cost of training for takmg and analyzing samples Cost of drills to assure that timing and accuracy specifications are maintained
. Arbinictmiive costs metaA with equipment with regulatory specifications (e.g., reportability issues)
Costs associated with NRC audits / inspections Utility estimates range from S50,000 to 5400,000 per year in O&M /
administrative costs Wolf Creek (lead plant) estimates $155,000/yr exclusive of capital cost a
W:DD l
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WOG Relaxation of PASS Requirements
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= The PASS requirements proposed by the WOG are consistent with public health and safety, and accident management needs EOPs SAMG EALs PARS Offsite Dos? Assessment The proposed Pi SS requirements will ittain the capability to obtain a
samples in the long term after a core damage accident; specific regulatory requiremenia for timing and accuracy will be modified The PASS requirements proposed by the WOG are a cost effective e
means of assuring plant safety W:3DD 8
ISSUES AND FOLLOW-UP ACTIONS DISCUSSED DURING 3125/99 NRC/WOG MEETING ON WCAP-14986-P, REV 1,
" Westinghouse Owners Group Post Accident Sampling System Requirement:
A Technical Basis" The following is_ a list of comments, questions, and issues on WCAP-14986-P which were
- provided to the Westinghouse Owners Group (WOG) on March 15,1999, for discussion during the March 25,1999, meeting between representatives from the Office of Nuclear Reactor Regulation (NRR) and WOG. The discussions held and follow-up action items from that meeting are in italics.
EVALUATION Ot' RECOMMENDATIONS
- 1. Sample: RCS Dissolved Gases WCAP Recommendation: Delete From PASS The WCAP recommendation is based upon an analysis of where information on dissolved gasses is used in the EOPs.
Issues:
It is not clear that other post-accident items which might for some designs be affected by dissolved gasses, such as vessel level instrumentation and emergency core cooling system high pressure injection pump performance, were addressed. Please provide a more comprehensive discussion of this topic to address other affected items including, but not limited to, the items cited.
Discussion:
WOG stated that PASS samples are not utilized to take actions to address these concerns during an accident.'
Action:
NRR to evaluate whetherits concern need to be addressedin the WOG topical.
Same issue as for RCS dissolved gases-
- 3. Sample: RCS Oxygen WCAP Recommendation: Delete From PASS This measurement is specified in Regulatory Guide 1,97. The presence of oxygen can enhance stress corrosion cracking (SCC) caused by chlorides. The WCAP does not recommend measuring oxygen in reactor coolant but indicates that GCC can be prevented by either ensuring that oxygen concentration is low or by adiusting pH.
Issues:
It is not clear how this SCC control can be achieved when pH and oxygen concentration will not be measured.
l ATTACHMENT 3 a
1 Discussion:
Issue not discussed due to unavailability of NRR personnel. A teleconference will be scheduled to discuss issue if needed.
In order to make a pH estimation, the chemistry of the incoming water from all sources to RCS should be known and there should be a procedure at hand for calculating the resulting pH by the plant personnel. Will these considerations be addressed in the proposed procedure?
Discussion:
WOG stated that a procedure is not necessary because this type of estimation is considered to be ' skill-of-the-craft."
The WCAP does not discuss whether measurements of boron in the sump might provide information on boron precipitation or boron dilution during an accident. Was this considered when the recommendation for relaxing the sample time was made? Further discussion is needed on this item.
Discussion:
NRR stated that current ongoing work on this issue needs to be considered.
Action:
NRR to evaluate current work on this issue cnd determine if further action is needed by WOG to address this issue in its topical.
8.
Sample: RCS Radionuclides WCAP Recommendation: Delete From PASS WCAP-14986 concludes that the capability to obtain post accident samples of reactor coolant for radionuclide content is not needed and recommends that this capability be removed from the licensing basis. The rationale for this conclusion is that there are other indicators (e.g., core exit thermocouples and containment high range monitors) which can be used for performing j
core damage assessments and that these indicators are available earlier than PASS samples.
Furthermore, WCAP-14986 states that the PASS samples would not provide any useful information regarding the extent of core damage because of limitations related to accident conditions and sample capabilities (e.g., plate out in sample lines).
Issues:
The need for PASS is described in the NUREG-0737, " Clarification of TMI Action Plan Requirements" and Regulatory Guide (RG) 1.97, " instrumentation for Light-Water-Cooled Nuclear Power Plants to Assess Plant and Environs Conditions During and Following an Accident." NUREG-0737 specifies that the PASS have the capability to promptly quantify certain radionuclides that are indicators of the degree of core damage. RG 1.97 specifies that the isotopic analysis serves the purpose of accident release assessment. Although othu indicators are available to make an assessment of the degree of core damage, PASS samples would provide information usefulin :onfirming or refining estimates of coro damage. More importantly, PASS information will be useful in refining release assessments which may be based upon assumed source terms. These dose assessments can be used to confirm (or refine, if necessary) the adequacy of the in;tial protective action recommendation which was based upon plant conditions Further discussion is needed on these issues.
Discussion:
WOG stated that radionuclide samples are not required for any EOP, SAMG, or emergency planning activity except for intentional releases and that fixed in-plant instrumentation is used as the primary information based on timeliness and reliability. NRR stated that, although PASS l
results may not be used forinitialprotective action recommendations, knowledge of the radionw' ides release from the core to the coolsnt would be usefulin confirming the adequacy l
of protective action recommendations or identifying the need to expand protective action i
l recommendations if necessary.
- 10. Sample: Containment Radionuclides WCAP Recommendation: Delete From PASS WCAP-14986 conc ludes that the capability to measure the radionuclide content of the -
l containment atmosphere is not needed and recommends that this capability be removed from the licensing basis. The rationale for this conclusion is that there are other indicators (e.g., core exit thermocouples and containment high range monitors) which can be used for performing core dan. age assessments and that these indicators are available earlier than PASS samples.
Furthermore, WCAP-14986 states that the PASS samples would not provide any useful information regarding the extent of core damage because of limitations related to accident conditions and sample capabilities (e.g., plate out in sample lines).
1 issues:
The need for PASS is described in the NUREG-0737 " Clarification of TMI Action Plan Requirements" and Regulatory Guide (RG) 1.97, " Instrumentation for Light-Water-Cooled Nuclear Power Plants to Assess Plant and Environs Conditions During and Following an Accident." NUREG-0737 specifies that PASS have the capability to promptly quantify certain radionuclides that are indicators of the degree of core damage. RG 1.97 specifies that the isotopic analysis serves the purpose of accident release assessment. Although other indicators are available to make an assessment of the degree of core damage, it seems that PASS samples would provide information usefulin confirming or refining estimates of core damage.
More importantly, it seems that information regarding the radionuclide concentration in the containment provides the best information on the source term for use in performing dose assessment of the potentialimpact of a release from the containment. This information will be usefulin refining release assessments which may be based upon assumed source terms.
These dose assessments can be used to confirm (or refine, if necessary) the adequacy of the initial protective action recommendation which was based upon plant conditions. Further discussion is needed on these issues.
Discussion:
WOG stated that radionuclide samples are not required for any EOP, SAMG, or emergency planning activity except for intentional releases and that fixed in-plant instrumentation is used as the primaryinformation based on timeliness and reliability. NRR stated that, although PASS results may not be used forinitialprotective action recommendations, knowledge of the radionuclides release from the core to the containment would be usefulin confirming the adequacy of protective action recommendations oridentifying the need to expand protective action recommendations if necessary. NRR stated that knowledge of the relative ratios of radionuclides in containment can be used in dose assessment calculations to provide a more accurate assessments from that obtained using defaults. Representatives from Wolf Creek (the lead plant for applying the Topical) stated that dose assessment are not very sensitive to changes in radionuclide inputs.
Actions:
NRR and Wolf Creek to discuss further the effect of different radionuclide ratios on projected doses.
- 12. Sample: Sump Chlorides WCAP Recommendation: Delete From PASS WCAP-14986 proposes to delete the capability for measuring chlorides in the containment. In its analysis it considers the case of brackish or salt water plants having no passive pH control.
WOG suggest that in this case the amount of chloride in the sump could be estimated by monitoring level of sump water and predicting its chloride content from the chloride content in the water sources injected into the containment, Issues:
How accurate is this method, especially when this estimate is performed by the plant operators engaged in several other pressing operations.
Discussion:
l Issue not discussed due to unavailability of NRR personnel. A teleconference will be scheduled i
to discuss issue if needed.
I
i The WCAP does not discuss whether measurements of boron in the sump might provide information on boron precipitation or boron dilution during an accident. Was this considered when the recommendation for relaxing the sample time was made? Further discussion is a
needed on this issue.
i l
i
Discussion:
Same as underissue Number 6.
- 14. Sample: Sump Radionuclides WCAP Recommendation: Delete From PASS lssues: Same as for Containment and RCS Radionuclides sample.
Discussion:
Same as underissue numbers 8 and 10.
GENERAL COMMENT
S / QUESTIONS
- 1. Removal of Requirements from Licensing Basis WCAP-14966 recommends 'that the capability to obtain certain samples be deleted as a requirement but retained to assist in planning long term recovery action (but not within the plant.
licensing basis). It is not clear what is meant by removing the capability from the licensing basis. What controls would be applied to ensure licensee's capabilities would not be degraded or eliminated.
Discussion:
WOG discussed that the form and location of commitments relative to PASS differ among licensees with some being in license conditions, some in technical specifications, and others in the Final Safety Analysis Report. NRR discussed a desire for uniformity in the form and location of PASS commitment resulting as a result oflicensees adopting the PASS topical.
WOG agree that this was desirable.
Action:
WOG to evaluate how PASS commitments are captured under the standard technical specifications. NRR to evaluate what controls may be appropriate for the PASS.
- 2. Benefit of Modification of PASS Requirements Neither the WCAP nor the pilot plant submittal identified a significant burden with maintaining the PASS capabilities (the pilot plant cubmittal did identify a significant burden with maintaining i
the on-line sampling capability ). The pilot plant identified that it had the capability to obtain and analyze a grab sample (this is currently a backup to the online system). It is acceptable for the licensees to discontinue use of on-line PASS system, as long as the capability to promptly obtain and analyze PASS samples exist.
Discussion:
WOG listed the areas where cost savings could be realized from the proposed changes in PASS commitments. NRR stated that it appeared that the cost of PASS was primarily associated with tho in-line PASS components. NRR stated that removing the in-line systems and relying on grab sample based systems was acceptable option. NRR stated that in order to understand the cost savings associated with changing the NUREG-0737 criteria for PASS, an evaluation of the cost of a grab sample system (capable of obtaining and analyzing samples with 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> of the decision to do so) and a grab sample system (with no time criteria) was needed.
Action:
WOG and NRR to hold a telecon to discuss this issue further.
- 3. Plugging of PASS Lines WCAP-1M86 states that one rationale for not taken PASS samples is due to the potential for plugging.n the sample lines. However, in accordance with NUREG-0737, these sample lines
- were to be designed to preont plugging and plateout. Further information is needed to evaluate the predicted extent of plugging and plateout in the sample lines (see also specific comment #3).
Discussion:
WOG stated that there are two issues: (1) plugging oflines due to aerosolproduction from core concrete interaction and (2) plate out in the sample lines. NRR stated that it is further evaluating this issues considering guidance provided in Regulatory Guide 1.21.
SPECIFIC COMMENTS 1.
Page 3, Para. 5 WCAP-14986 states that " Regulatory Guide 1.97 represents the latest NRC positions on post accident sampling and, as such, supersedes the requirements in NUREG-0737." Regulatory Guide 1.97 provides methods acceptable to the NRC for meeting the requirements of General Design Criteria 64 in Appendix A to 10 CFR Part 50. NUREG-0737 provides clarification to TMI Action plan requirements which were imposed on licensees by orders. Regulatory Guide 1.97 1
does not supercede NUREG-0737 requirements imposed by orders.
Discussion NRR stated that this comment was provided to WOG forits use in clarifying the topical.
2.' Page 4, Table 1 The table contains an editorial error (10 mci /mi should be 10 pCi/ml). This error (use of mCiin place of pCi)is repeated in a number of places in the WCAP.
Discussion NRR stated that this comment was provided to WOG forits use in correcting en apparent editorial error.
3 Page 8, Paragraph 2 WCAP-14986 states that recent analytical studies have indicated that dense aerosol concentration in the RCS and the containment could plug sample lines. Please provide the 1
referred to studies. Clarification 11 to NUREG-0737 item li.B.3 states that the PASS should have " Provisions for purging sample lines, for reducing plateout in sample lines, for minimizing sample loss or distortion, for preventing blockage of sample lines by lose material in the RCS or containment." Please provide further information on why the provisions put in place to meet this NUREG-0737 item are not adequate.
Discussion:
WOG stated that plugging of sample lines may occur due to aerosols produced from core-concrete interactions after the core has gone ex-vessel.
4.
Page 9, Paragraph 1 WCAP-14986 states that the investigation that resulted in development of a new core damage assessment methodology concluded that the results of radioactivity analyses of samples of plant fluids was too unreliable to mt ke prediction regarding the amount of core damage that has occurred. The rationale for this conciusion was that the transport and deposition of radionuclides in the plant is very dependent on the details of the accident.
Further information is needed to conclude that PASS cannot be used to predict the amount of core damage. It seems that PASS samples can provide additionalinformation to supplement that provided by other indications. In particular the PASS can provide indication of the extent of core damage relative to clad damage versus core overtemperature or core melt by the presence of volatiles or non-volatiles in the samples.
Discussion:
This issue willbe addressed as part of the review of WOG Topical on Core Damage Assessment.
- 5. Page 9, Paragraph 2 WCAP-14986 states that radiological analysis of plant fluids was not useful for emergency action level classification. It is not clear what the spectrum of accidents were evaluated that lead to this conclusion. The criteria included in the EAL scheme equates to approximately 2 -
5% clad damage. At these levels of clad damage, it is not clear that other parameters would prompt classification. Paragraph 3 on page 16 describes classification of a reactivity excursion event. It seems that a reactor coolant sample may be the only indication of clad damage for this event.
Discussion:
Due to time constraints this item was not discussed in detail during the meeting.
- 6. Page 11, Paragraph 5 WCAP-14986 state that the NRC approved deletion of the requirement for heat tracing of sample lines. The NRC stated in that a licensee that utilizes iodine in its core-damage assessment procedures must include appropriate design consideration to ensure representative sampling. It is not clear how xenon and/or kryton isotopic analysis can be used to ascertain the degree and tvoe of core damage.
Discussion:
Due to time constraints this item was not discussed in detail during the meeting.
p
+
- 7. Page 16, Paragraph 1 It is not clear what is meant by the statement that "the third class of accident is similar to the composite core damage classifications described in NUREG-0737."
Discussion:
WOG indicated that the statement in question was an editorial error and should have stated "the classes of accidents are similar..."
. 8. Page 27, paragraph 1 WCAP-14986 states "from the perspective of emergency response, there are only three levels of core damage that are important: no damage, fuel rod cladding damage and fuel over temperature damage. The majority of the noble gas and volatile fission products are already released from the fuel prior to the onset of core melting. These are also the most important fission products (i.e. noble gases, iodines and cesiums) from an offsite radiological protection perspective. The small quantities of nonvolatile fission products that may be released only at core melting are not as important with respect to emergency response activities." This needs to be further justified, i.e., provide the information regarding what the additional quantities of radioactive material are released and how ex-vessel releases were modeled.
Discussion:
WOG indicated that the statements made in the Topical are consistent with conclusions provided in the Seabrook EP studies (reference ?LG-0432, p5-7) and AP600 dose calculations (reference Design Cedification Document Table 49-2 and 3).
- 9. Page 43, Section 4.3.2
-WCAP-14986 provides information regarding the use of source term information to make dose assessment. This section discusses various ways that the source term can be obtained, including use of precalculated values (e.g., from design basis or PRA sources) or use of containment high range area radiation monitor, but does not provide information on the re!ative accuracy of the different means of obtaining source term data.
Discussion:
WOG stated that it did not attempt to quantify uncertainty in the different source term data.
- 10. Page 44, Section 4.3.3 WCAP-14986 states that the NEl EAL scheme suggests a value of 300 mci /cc equivalent 1-131 as an EAL criterion at the Unusual Event level. This is incorrect. As identified previously the value is 300 pCi/cc. Furthermore the event is classified in the fission product barrier at the Alert level unless other fission product barriers are lost or potentially lost (in which case it is classified at a higher levei).
Discussion WOG stated that the Topical was in error.
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- 11. Page 44, Section 4.3.3 WCAP-14986 discusses an assessment performed to identify possible accident sequences where the RCS fission product inventories can approach EAL trigger values. Please provide details of the assessment. In particular provide information on how reactivity excursion events and events involving the potential clad damage due to flooding with cold water were evaluated.
Discussion:
Due to time constraints this item was not discussed in detail during the meeting.
COMMENTS SPECIFIC TO LEAD PLANT (WOLF CREEK) APPLICATION OF WCAP Note: Due to time constraints the following items were not discussed during the March 25,1999, meeting. However, these items were discussed in a teleconference held on March 29,1999.
- 1. For several PASS functions, the Wolf Creek Nuclear Operating Company (WCNOC) submittal states that the post-accident sampling function can be deleted, but that "..for long term monitoring, the capability will be retained (but not within the plant licensing basis).. "
Please provide the following:
- a. Clarification of what is intended by the statement that the capability would be retained for long term monitoring. A specific statement of which sampling and analysis capabilities and/or hardware would be retained and which would be deleted or relaxed
- should be provided for each PASS function. This should clearly indicate where WCNOC plans to retain / delete / relax the on-line monitoring capabilities, the grab sample capabilities, the time required to obtain samples, and the time required to analyze i
l samples.
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- b. Clarification of what is intended by the statement "not within the plant licensing basis." If this means that the system or function is completely removed from the FSAR, explain what controls would prevent the system and function from being eliminated at a later date without the approval of the NRC.
Discussion:
Wolf Creek representatives stated that Section 18.1 of the UFSAR would be modified to reflect the remaining PASS capabilities. Technical Specifications are very general regarding the PASS and do not need to be changed.
- 2. For several PASS functions, the WCNOC submittal states that the parameter can be approximated from calculations (e.g., RCS and sump pH). Please describe the calculation aids currently in place or planned at Wolf Creek Generating Station (WCGS) to predict the chemical content of the RCS or sump water (i.e., pH and chlorides) based on the quantities and chemical content of water added to the RCS or sump from other sources.
Discussion:
Wolf Creek representatives stated that no calculational aides are considered to be necessary as this is within the skill of the craft.
- 3. The WCNOC proposal regarding RCS radionuclide sample and analysis capabilities is very vague. It implies that the PASS function will be deleted for the short term (transient phase),
but that the related EALs will not be deleted. Please describe how radionuclide samples of the reactor coolant system will be obtained for use in classifying events using these EALs.
Discussion:
NRR discussed whether RCS samples containing 60 pCi/gm dose equivalent iodine could be taken with the normal sample system Wolf Creek representatives stated that they were unsure if this was the case. Wolf Creek representatives stated that the purpose of the EAL was to identify fuel damage and that other indicators existed for this.
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- 4. The WCAP and the text of the WCNOC submittal seems to indicate that containtnent atmosphere hydrogen can be determined via either: (1) the safety grade on-line hydrogen I
monitor (required by 10CFR50.44), or (2) sampling and analysis using PASS, provided the initial measurement can be made within 30 minutes, and at 10 to 15 minute intervals thereafter. This discussion does not indicate or discuss WCNOC's proposal regarding PASS hydrogen measurement capabilities. This is only mentioned in Table 1. The l
statement in the table should be brought into the text and discussed further.
Discussion:
Wolf Creek representatives stated the safety grade on-line hydrogen system was not a part of PASS and would not be effected by the proposed changes to PASS.
- 5. The discussion of containment atmosphere oxygen on page 19 of the WCNOC submittal states that the capability to measure containment oxygen concentration is not a NUREG-0737 or a Regulatory Guide 1.97 function for PWRs. However, containment oxygen is indicated to be a required parameter on page 6 and 7 of the submittal. Please clarify this apparent inconsistency.
Discussion:
l Wolf Creek representatives stated that containment oxygen is a Regulatory Guide 1.97 function for PWRs.
- 6. The discussions in Section IV indicate that long term monitoring capabilities will be retained for several PASS functions. However, Table 1 does not indicate this, and simply states that these functions would be deleted from PASS. Table 1 should be modified to identify thor:,e areas where long term monitoring capabilities will be retained.
Discussion:
Wolf Creek representatives stated that the remaining PASS functions would be described in UFSAR Section 18.1.
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Additionallasues Discussed During the March 29,1999 Telecon with Representatives from Wolf Creek.
Issue 1: Cost to maintain PASS capabilities Representatives from Wolf Creek provided the following estimates of the cost to maintain different PASS capabilities. The current capability is an in-line system with a grab sample backup.
Operation and Maintanence (O&M) per year One Time expenditure Capital imorovement Current Capabilities
$195,000
$2,000,000 (upgrade for Y2K)
Grab Sample Capability
$26,000
$150,000 (within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />)
Grab Sample Capability
$26,000
$50,000 (no time commitment)
Issue 2:
Impact of Changes to Radioisotope inputs on Dose Assessment Results Representatives from Wolf Creek stated that, although input of individual radioisotopes being released into the dose assessment code does not heve a large impact on dose assessment results, a change in the input of the ratio of radioactive noble gas to iodine being released can have a significant impact on the dose assessment restits. The Wolf Creek dose assessment code has the capability for inputting changes to the noble gas to iodine ratio.
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