ML20206S372
| ML20206S372 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 07/29/1998 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-3117, NUDOCS 9905210109 | |
| Download: ML20206S372 (21) | |
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Date Issued: July 29, 1998 Date Certified: August 27, 1998 g
j jj ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 1
ADVANCED REACTOR DESIGNS SUBCOMMITTEE MEETING MINUTES JULY 7, 1998 i
ROCKVILLE. MARYLAND The ACRS Subcommittee on Advanced Reactor Designs met on July 7, 1998, at 11545 Rockville Pike. Rockville. Maryland, in Room T-2B3.
The purpose of the meeting was to gather information regarding the AP600 test and analysis program, and responses to ACRS questions asked during previous meetings.
Messrs. Noel Dudley and Paul Boehnert were the cognizant ACRS staff engineers for this meeting. The meeting was convened at 8:30 a.m. and adjourned at 5:10 p.m. on July 7, 1998.
ATTENDEES AGS J. Barton Chairman W. Shack. Member M. Fontana. Member G. Wallis, Member T. Kress. Member I. Catton, Consultant D. Miller. Member P. Boehnert. Staff Engineer D. Powers. Member N. Dudley. Staff Engineer R. Seale. Member NRC STAFF T. Quay. NRR J. Lee, NRR T. Kenyon NRR J. Wilson, NRR M. Snodderly, NRR WESTINGHOUSE ELECTRIC COMPANY B. McIntyre, Westinghouse J. Gresham, Westinghouse W. Brown. Westinghouse C. Haag. Westinghouse M. Corletti. Westinghouse M. Young. Westinghouse A. Gagnon. Westinghouse There were no written comments or requests for time to make oral statements received from members of the public. An attendance list of the NRC staff and public is available in the ACRS office files and will be made available upon request.
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Advanced Reactor Designs Subcomittee 2
July 7, 1998 SUBCOMMITTEE CHAIRMAN INTRODUCTION Mr. John Barton, Subcommittee Chairman, convened the meeting at 8:30 a.m. and noted that this meeting was the 35th meeting of an ACRS Subcommittee or Full Committee related to the review of the AP600 design. He stated that the intent of the meeting was to resolve any open issues or questions that the Subcommittee members or consultants had concerning the staff's review of the AP600 design. Mr Barton recessed the meeting for a half hour to allow the Subcommittee members to read the recently received documents regarding subjects that would be presented later in the day.
DISCUSSION OF AGENDA ITEMS Introduction - Mr. Brian McIntyre Westinghouse Mr. Brian McIntyre, Westinghouse, introduced Westinghouse's presentation by updating the Subcommittee on the sale of the Westinghouse Electric Company.
Closure of ACRS Questions - Mr. Brian McIntyre Westinghouse Mr. McIntyre explained how the aerosol removal model.was used with an amalgamation of the source term and a single thermal hydraulic scenario. He noted the timing of all severe accidents for the AP600 are similar to the stylized scenario and that the credit for the aerosol removal mechanisms were only applicable for the AP600 design.
Mr. McIntyre then presented answers to previous ACRS questions concerning the following:
models used to calculate aerosol removal rates, how the LOFTRAN code calculates flow in closed loop systems, fuel clad temperature during a reactor coolant pump locked rotor event, venting of the primary residual heat removal system, analyses of pipe breaks downstream of automatic depressurization valves.
e potential for increased response times due to security design.
credit being given for natural deposition of aerosols.
use of fire doors and dampers to prevent the spread of smoke, qualification of passive autocatalytic recombiners (PARS).-and the g value used to calculate the production of nitric acid.
=
A list of questions asked by the ACRS members during their review of the AP600 design and the basis for closing the concerns raised by the questions is j
provided in Attachment 1.
i
E s-i i.
. Advanced Reactor Designs Subcommittee July 7, 1998 i
The Subcommittee members. Westinghouse, and the NRC staff discussed the following:
deposition of aerosols due to diffusiophoresis and thermophoresis.
differing assumptions used in the LOFTRAN and NOTRUMP codes, use of engineering judgement in evaluating potential accident scenarios.-
weaknesses in fire probabilistic risk assessments, the adequacy of present qualification tests for PARS, and
=
the effect of using realistic g values for nitric acid production on calculating off-site dose rates.
Resolution of Issues Associated With its Test and Analysis Program -
Messrs. Jim Gresham, Michael Young, and William Brown. Westinghouse Westinghouse representatives provided information regarding the ACRS open issues associated with the AP600 test and analysis program. These issues were cited in the Committee's interim letters on the AP600 design certification review and were raised e.t recent meetings of the Thermal-Hydraulic Phenomena Subcommittee.
Mr. Jim Gresham, Westinghouse, discussed the resolution of passive containment system issues that were cited in the February 19, 1998 ACRS Interim Letter.
l These 10 Issues are:
1)
Justification for use of incorrect expression in rate-of-pressure-change l
equation (Equation 34. WCAP-14845. Revision 2).
2)
Justification for inappropriate cancellation of partial derivative function to arrive at Equation 34.
3)
Re-evaluation of derivation and quantification of scaling pi groups resulting from correction of Equation 34.
i 4)
Justification for use of well-mixed assumption in the WG0THIC code for calculation of containment behavior.
5)
Justification for use of steady-state testing in the Large Scale Test
- facility to validate transient heat transfer correlations in the WGOTHIC
. code.
6).
Justification for the normalization of rate-of-pressure change term in Equation 34.
l I
3 Advanced Reactor Designs Subcomittee 4
July 7. 1998 7).
Technical basis for the treatment of the cooled containment boundary laminar sublayer in the WGOTHIC code.
8)
Validation basis for assuming a low elevation for main steamline break events.
9)
Justification for appropriate margin in the calculated peak containment pressure.
10)
Quantification of the impact of the incorrect measurement of mass and energy changes, which occurred during the large scale tests on the usefulness of the test data for validating the WG0THIC code.
Dr. Catton observed that the Westinghouse responses appear to justify bad modeling on its part.
He stated that the passive containment system design is robust, as was proved by the testing performed at the German HDR test facility.
Dr. Fontana said that Westinghouse should have performed a true best-estimate analysis of the passive containment system accident response, then should have added conservatism for margin.
Messrs. Gagnon, Young, and Brown made presentations on the following open issues relative to the AP600 reactor coolant system:
basis for drift flux model of horizontal flow in NOTRUMP:
Oregon State University's automatic depressurization system (ADS) 1-2 flow predictions using the NOTRUMP code:
demonstration of level penalty conservatism using the NOTRUMP code:
basis for the liquid entrainment model used in the NOTRUMP code:
multi-loop scaling for ADS-4 during the in-containment refueling water storage tank (IRWST) transition period:
description of the pressurizer flooding model used in the NOTRUMP code:
evaluation of the sensitivity of the assumed heat loss distribution observed in the SPES-2 facility during the LOFTRAN and NOTRUMP code validation efforts:
clarification of the inadequacies identified in the NOTRUMP code and the steps taken to compensate for these inadequacies:
s Advanced Reactor Designs Subcomittee 5
July 7, 1998 addition of a description of the interrelationships among the LOFTRAN, THINC-IV, and WESTAR codes and test data in the AP600 Standard Safety Analysis Report (SSAR):
identification of the channel-to-channel mixing coefficients used in the
=
LOFTRAN THINC-IV, and WESTAR codes: and description'of the break area sensitivity study of small-break loss-of-a coolant accidents (LOCAs) that ensured the process, which compensated for excluding the momentum flux terms in the NOTRUMP code, is robust for a range of blowdown rates.
Westinghouse identified inadequacies in the NOTRUMP code and undertook compensatory actions.
In response to Dr. Wallis, Mr. Young stated that Westinghouse will document the cautions / restrictions placed on this code with regard to its future use.
Dr. Kress asked that Dr. Zuber be consulted with regards to Westinghouse *s resolution of the issue of multi-loop scaling for the ADS-4 to IRWST transition period.
Dr. Zuber was contacted and subsequently stated that he found the Westinghouse resolution for this issue to be acceptable.
Mr. McIntyre noted that Westinghouse had provided Dr. Catton with material related to the issue of evaluating the sensitivity of the assumed heat loss distribution observed in the SPES-2 facility in the context of LOFTRAN and i
NOTRUMP code validation efforts.
Dr. Catton committed to provide his comments on the Westinghouse resolution of this matter to Dr. Kress, prior to the July 8, 1998 ACRS meeting.
[ Note: in his report to the ACRS of July 8,1998, Dr.
Catton indicated that the data from the SPES-2 facility would not impact the conclusions reached by Westinghouse.]
SUBCOMMITTEE COMMENTS AND RECOMMENDATIONS Dr. Powers stated that the issue of weak fire probabilistic risk assessments should be taken up by the ACRS on a generic basis.
STAFF AND INDUSTRY COMMITMENTS
,Mr. McIntyre stated that Westinghouse planned to provide revisions to the AP600 SSAR, PRA, and Tier 1 Material within the next several weeks. He stated that the revisions would resolve all open issues.
o Advanced Reactor Designs Subcomittee 6
July 7. 1998 Ths staff committed to verify that Wes.tinghouse commitments to revise the AP600 SSAR. PRA, and Tier 1 Material are completed and that the revisions adequately meet regulatory requirements.
SUBCOMMITTEE DECISIONS The Subcommittee plans to draft a letter for consideration at the July 8-10, 1998 ACRS meeting.
The Subcommittee requested that Westinghouse provide presentations at the July 8, 1998 ACRS meeting, on the passive containment system (PCS) issues related to the assumption that the containment interior is well-mixed during an accident and to the use of incorrect equations in the scaling process. The Subcommittee also requested that Westinghouse provide presentations on the reactor coolant system issues related to the NOTRUMP code, use of the drift flux model for calculating horizontal flow, the pressurizer surge line flooding model, and the basis for the liquid entrainment model.
During the June 17-18, 1998 Advanced Reactor Designs Subcommittee meeting, Westinghouse was asked to provide presentations at the July 8,1998 ACRS meeting, on the inspections, tests, analyses, and acceptance criteria (ITAAC) process:. adverse systems interaction evaluations: results of the Level 1 PRA:
and' modifications made to the security plan.
FOLLOW UP ACTIONS This is the last Subcommittee meeting related to the ACRS review of the AP600 design. No further ACRS actions or activities are planned. The Subcommittee plans to review the Final Design Certification when it becomes available.
PRESENTATION SLIDES AND HANDOUTS PROVIDED DURING THE MEETING The presentation slides and handouts used during the meeting are available in the ACRS office files or as attachments to the transcript.
BACKGROUND MATERIAL PROVIDED TO THE SUBCOMMITTEE 1.-
U.S. Nuclear Regulatory Commission. " Advance Final Safety Evaluation Report Related to the Certification of the AP600 Design." May 1998 (Predecisional Information).
2.
Westinghouse Electric Corporation Report "AP600 Standard Safety Analysis Report." dated June 26,1992 [ updated through Revision 23 issued May 18, 1998].
p i
l Advanced Reactor Designs Subcomittee 7
July 7. 1998 l
3.,
Westinghouse Electric Company Report, "AP600 Probabilistic Risk Assessment," dated June 26, 1992 [ updated through Revision 11 issued March 19983 4.
Westinghouse. Electric Company Report, "AP600 Tier 1 Material." dated June 26.1992 [ updated through Revision 5 issued May 7.1998].
l 5.
Letter dated February 19, 1998. from R. L. Seale Chairman. ACRS. to L.
Joseph Callan, Executive Director for Operations. NRC,
Subject:
Interim Letter on the Safety Aspects of the Westinghouse Electric Company Application for Certification of the AP600 Plant Design.
6.
Letter dated April 9,1998, from R. L. Seale Chairman, ACRS. to L.
Joseph Callan, Executive Director for Operations. NRC.
Subject:
The Safety Aspects of the Westinghouse Electric Company Application for Certification of the AP600 Plant Design-Interim Letter 2.
7.
Letter dated June 15. 1998, from R. L. Seale, Chairman, ACRS. to L.
Joseph Callan, Executive Director for Operations. NRC
Subject:
The Safety Aspects of the Westinghouse Electric Company Application for Certification of the AP600 Plant Design-Interim Letter 3.
8.
U.S. Nuclear Regulatory Commission, Draft NUREG-1512. " Draft Safety Evaluation Report Related to the Certification of the AP600 Design,"
November 1994.
9.
U.S. Nuclear Regulatory Commission. Supplement to the " Draft Safety Evaluation Report Related to the Certification of the AP600 Design,"
April 1996.
10.
Westinghouse Electric Corporation WCAP-14812 Revision 2. " Accident Specification and Phenomena Evaluation for AP600 Passive Containment Cooling System," April 1998 (Proprietary).
11.
Westinghouse Electric Corporation, WCAP-14845, Revision 3. " Scaling Analysis for AP600 Containment Pressure During Design Basis Accidents."
March 1998 (Proprietary).
~
12.
Westinghouse Electric Corporation WCAP-14326. Revision 3. " Experimental Basis for the AP600 Containment Vessel Heat and Mass Transfer Correlations," May 1998 (Proprietary).
13.
Westinghouse Electric Corporation. WCAP-14135 Revision 1. " Final Data Report for PCS Large-Scale Tests, Phase 2 and Phase 3." April 1997 (Proprietary).
14.
Westinghouse Electric Corporation. WCAP-14382, Revision 0, "WGOTHIC Code Description and Validation." May 1995 (Proprietary).
15.
Westinghouse Electric Corporation. WCAP-14407. Revision 3. "WGOTHIC Application to AP600," April 1998 (Proprietary).
l
I Advanced Reactor Designs Subcommittee 8
July 7. 1998 4
16 Of.fice of Nuclear Regulatory Research (RES) Report, RPSB-98-04, "Phenomenology Observed in the AP600 Integral Systems Test Programs Conducted in the ROSA-AP600. APEX. and the SPES-2 Facilities." D.
Bessette RES, M. DiMarzo. University of Maryland, P. Griffith, Massachusetts Institute of Technology, April 1998.
17.
Letter dated July 1, 1998, from B. McIntyre. Westinghouse, to NRC:
Attention:
J. Larkins, ACRS. transmitting Response to ACRS Request for 1
NOTRUMP Break Area Sensitivity Study.
18.
Letter dated July 2, 1998. from B.
McIntyre, Westinghouse, to NRC:
Attention:
J. Larkins, ACRS.
Subject:
Responses to ACRS Reactor Coolant System Issues.
19.
Letter dated June 25, 1998. from B.
McIntyre. Westinghouse, to NRC:
Attention:
J. Larkins, ACRS,
Subject:
Closure of ACRS Thermal Hydraulic Subcommittee Items for June 11-12, 1998 Meeting.
l l
NOTE: Additional details of this meeting can be obtai-ned from a transcript l
available in the NRC Public Document Room, 2120 L Street, N.W.,
l Washington, D.C. 20006. (202) 634-3274. or can be purchased from Ann Riley & Associates. LTD., 1250 I Street, N.W., Suite 300 Washington, D.C. 20005, (202) 842-0034.
l
Attachment:
ACRS Questions Concerning the AP600 Design l
1
i
'4 ATTACHNENT 1
ACRS QUESTIONS CONCERNING THE AP600 DESIGN 3Out-98 '
Member Start Date End Date
==
Description:==
Catton 1/11/95 7/23/96 Mr. Scobel agreed to provide a copy of Theofanous' report from the
)
Advanced Reactor Severe Accident Program (ARSAP) 1 Basis for Closure:
Received report DDE/ID-10541, dated June 1996
==
Description:==
Catton 1/11/95 8/8/96
]
Requested the engineering basis for the positioning of hydrogen ignitors in the containment Basis for Closure:
ACRS meeting:
SSAR Table 6.2.4-6
==
Description:==
Catton 1/11/95 6/11/98 Requestedjustificationoftheassumptionthattemperaturestratification will not occur in the containment during cooling system operation Basis for Closure:
T-H SUB. meeting: W accident analysis of passive containment system is bounding: data from German HDR test confirms atmosphere mixing
==
Description:==
Lindblad 1/11/95 5/13/98 Mr. Schultz was requested to provide an SSAR reference on how the AP600 design improved the inservice test program Basis for Closure:
SUB. meeting:
SSAR Section 3.9.6. does not explain why ISI test is better: examples of check valve ISI test 1
i Member Start Date End Date
==
Description:==
Michelson 1/11/95 5/14/98 Explain how galvanic corrosion on the containment vessel is prevented Basis for Closure:
SUB. meeting: steel shell enclosed in concrete on both sides with moisture seal that is inspected
==
Description:==
Michelson 1/11/95 5/13/98 Requested design description of vents / vacuum breakers on the top of the IRWST Basis for Closure:
SUB. meeting:
IRWST has dampers on top of tank
==
Description:==
Michelson 1/11/95 5/13/98 Requested explanation of what effect the freezing of the drain and supply lines would have on the containment cooling systems Basis for Closure:
SUB meeting: short drains to storm sewers prevent freezing: supply lines are enclosed and heat traced
==
Description:==
Michelson 1/11/95 4/1/98 Verify separation of class 1E battery room ventilation systems Basis for Closure:
SUB. meeting: Trains A+C separated from Trains B+D: HVAC systems shutdown and isolate upon~ detection of a fire I
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t l'
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a s
Member Start Date End Date
==
Description:==
Michelson 1/11/95 5/13/98-Requested explanation of the potential for creating a vacuum in the containment Basis for Closure:
SUB. meeting: Analysed for -40 degrees F. 48 mph winds outside and 120 degrees F, 100% humidity inside
==
Description:==
Carroll 5/31/95 6/29/95 Requested copy of DOE /ID-10460. "In-Vessel Coolability and Retension of a Core Melt" Basis for Closure:
Draft Report sent to MF. IC. TK RS. DP. DM: Copy of Final Report available in the ACRS Office
==
Description:==
Carroll 5/31/95 4/1/98 The number of security access points appear to be inadequate for neintenance outages i
Basis for Closure:
SUB. meeting: W modified design so that personnel did not have to leave protected area to access other vital areas
==
Description:==
Carroll 5/31/95 5/13/98 Verify that the initial test program for instrument air systems is more extensive than for previous designs Basis for Closure:
SUB. meeting:
initial test program requires instantaneous and slow air system depressurization tests 3
l:
1 Member Start Date End Date
==
Description:==
Carroll 5/31/95 2/3/98 Requested additional details on the leak detection methods needed to support Leak-Before-Break piping designs Basis for Closure:
SUB. meeting:
l
==
Description:==
Carroll 5/31/95 10/17/95 Requested copies of German Reports on erivironmental qualification of passive hydrogen re-combiners Basis for Closure:
l 6 reports sent to MF, IC. TK, and RS l
==
Description:==
Fontana 7/19/96 5/14/98 l
Requested additional information on the effects of a partially filled i
cavity on containment failure probability l
j Basis for Closure:
)
SUB. meeting: PRA assumes containment failure on RPV failure: limited analysis performed for ex-vessel steam explosion i
~
==
Description:==
Fontana 7/19/96 2/3/98 Requested presentaion on the safe shutdown end state l
Basis for Closure:
l SECY-94-084: acceptable PRHR performance, pipe rupture does not violate l'0 l
CFR 50.46 criteria: SD Evaluation Report l
4 i
1 i
i 2
F:
l.
Member Start Date End Date
==
Description:==
Kress 7/19/96 7/7/98 Requested W present the models on which aerosol removal rates are based:
mechanisms for aerosol deposition: and jusification for allowing credit Basis for Closure:
Paper on natural aerosol deposition presented at 3rd OEC0 Meeting on 6/15-18/98
==
Description:==
Lindblad 7/19/96 8/8/96 Requested copy of the URD specification or assumption of the time period a plant is disconnected from the electrical grid Basis for Closure:
ACRS meeting: URD Vol III, Chap 1. App A, p A.A-13
==
Description:==
Powers 7/19/96 4/1/98 Radiological consequences of loss of spent fuel pool cooling needs to be discussed, including chemical interactions i
Basis for Closure:
SUB. meeting:
24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to uncover fuel after SFP boils; passive makeup system available: steam vented to aux. building
==
Description:==
Subcommittee 7/19/%
6/30/97 Requested copy of RASPLAV facility report on in-vessel retention tests Basis for Closure:
18 reports sent to MF, IC TK, and DAP 1
i l
5 cc
{
i l
Member Start Date End Date i
1 l
==
Description:==
' Subcommittee 7/19/%
5/13/98 Requested analysis of steam generator tube response during severe accident temperature and pressure conditions Basis for Closure:
SUB. meeting:
PRA assumes SG tube failure for any high-temperature, high-pressure severe accident: DF of 100: sensitivity study
==
Description:==
Subcomittee 7/19/96 8/8/96 Requested an analysis for placement of hydrogen igniters in the containment Basis for Closure:
ACRS meeting:
SSAR table 6.2.4-6
==
Description:==
Carroll 12/4/96 4/1/98 Discussion of safety related HVAC systems in SSAR Section 9.4 should be referenced in Section 6.4 Basis for Closure:
SUB_ meeting: SSAR revised so that Sections 9-4 and 6-4, safety and non-safety HVAC systems, reference each other
==
Description:==
Miller 12/4/96 6/17/98 Requested details of the digital control systems associated with the radiation monitoring systems Basis for Closure:
SUB. meeting: question answered during discussions of other digital systems 6
r is
F
)
(
Member Start Date End Date
==
Description:==
Subcomittee 12/4/96 2/3/98 Requested definition of safe shutdown conditions for the reactor coolant system below 420 F and at or below normal operating pressure Basis for Closure:
SECY-94-084: acceptable PRHR performance, pipe rupture does not violate 10 CFR 50.46 criteria: SD Evaluation Report
==
Description:==
Subcommittee 12/4/96 4/1/98 Requested explanation reguarding conformance of the spent fuel pool cooling system design to staff policy position under review by the Commission Basis for Closure:
SUB. meeting: staff policy review position was never issued by the Comission: design meets regulatory requirements
==
Description:==
Kress 6/17/97 6/18/98 SRM on SECY-97-044: staff to work with ACRS to understand the concern on
" marginally adequate" design Basis for Closure:
SUB. meeting:
spray system designed to operate for 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> after core damage and may reduce aerosols by 50%
l
==
Description:==
Carroll 2/3/98 5/14/98 Staff explain why the use of leak-before-break design criteria for feedwater piping was unacceptable Basis for Closure:
SUB. meeting: predicted waterhammer stresses greater than pipe design:
four examples cited where waterhammer caused pipe failure 7
l
m l:
ls'.
Member Start Date End Date
==
Description:==
Carroll 2/3/98 5/13/98 Request for additional information regarding the check valve testing program Basis for Closure:
SUB. meeting: FSER section 3.9.6.5, p. 3-257, ISI tests on safety related check valves
==
Description:==
Carroll /DAP 2/3/98 6/17/98 Explain how the effect of smoke on digital equipment was analyzed Basis for Closure:
SUB. meeting:
digital equipment are designed for seismic and mild environments; separation: I&C Sub. will review on generic basis
==
Description:==
Powers 2/3/98 4/1/98 l
High-burnup fuel: address effects of power insertion ramp, black and grey rod reactivity, and iodine spiking in reactor coolant system Basis for Closure:
SUB. meeting: Reactor Fuels. Onsite Fuel Storage, and Decommissioning Subcomittee will review issue on a generic basis
==
Description:==
Seale 2/3/98 4/24/98 Discuss whether the required number of operators for the back shifts is excessive due to the use of digital I&C equipment Basis for Closure:
Dr. Seale: the number of operators needed in an advanced MCR should be addressed by the Human Factors Subcomittee 8
l
Member Start Date End Date
==
Description:==
Subcomittee 2/3/98 6/18/98 W agreed to discuss the suitability and results of the reactivity code used to predict the effects of rod ejection (SSAR Chap. 15)
Basis for Closure:
SSAR 15.4.8.2.1.4: Beta is conservative for BOL. Beta id optimistic for high burnup EOL: address high burnup fuel design later
==
Description:==
Subcommittee 2/3/98 6/18/98 W agreed to explain what databases were used to determine the activities of operators during plant events Basis for Closure:
SUB. meeting: Utility Requirement Document. NUREG/CR-2728. IEEE Standard 500. NSAC-154
==
Description:==
Subcommittee 2/3/98 5/13/98 W agreed to determine why containment hydrogen levels are displayed in the MCR but are not alarmed i
Basis for Closure:
SUB. meeting:
levels are alarmed in MCR. but are listed in Chap. 18 since no operator action required
==
Description:==
Subcommittee 2/3/98 5/13/98 W agreed to determine whether the containment hydrogen level indicators are diverse actuation devices Basis for Closure:
SUB. meeting: no automatic fuction performed by indicators: redundant channels are available 9
Member Start Date End Date f
==
Description:==
Carroll 4/1/98 6/17/98 Requested W consider terminating floor drain lines below drain sumps in order to ensure that airborne radioactivity and smoke cannot migrate Basis for Closure:
SSAR 9.3.5.2.2 drain lines 6" below pump suction line
==
Description:==
Carroll 4/1/98 6/18/98 W agreed to provide a presentation on adverse interactions during the presentation of the PRA Basis for Closure:
SUB. meeting: ACRS accepted WCAP 14477 Rev. 2 as a comprehensive assessment
~
==
Description:==
Carroll 4/1/98 5/15/98 The staff agreed to find out whether the SRP contains a section concerning chilled water refrigeration systems Basis for Closure:
SUB. meeting:
J. Lyons - the staff considered revising the SRP but decided not to add a section on refrigeration systems
==
Description:==
Carroll 4/1/98 5/13/98
. Requested W expl'ain how damage to pressurizer safety valves caused by relieving water is reflected in the PRA Basis for Closure:
{
SUB. meeting: Level 2 PRA assumes relief valves open and fail open d-10 l
~
.O Member Start Date End Date
==
Description:==
Catton 4/1/98 7/7/98 W agreed to explain how the LOFTRAN code calculates: flow in the CMT and PRHR loop, buoyancy, and Reynolds number Basis for Closure:
SUB. meeting: W 1etter dated July 2,1998 provided explaination of pressure drop calculations in LOFTRAN
==
Description:==
Wallis 4/1/98 7/7/98 Requested W provide a graph of fuel clad temperature for a RCP locked rotor event beyond 10 seconds: SSAR Fig. 15.3.3-7 Basis for Closure:
SUB. meeting: W letter dated July 2.1998 provided revised figure 15.3.3-7 with time extended to 20 seconds
==
Description:==
Wallis 4/1/98 6/18/98 The staff agreed to present its review of the W analysis of a pipe break downstream of ADS valves 1-3 Basis for Closure:
SUB. meeting: ADS 1-3 line break is bounded by LOCA and steam line break analyses
==
Description:==
Wallis 4/1/98 7/7/98 W agreed to explain how the PRHR piping to the IRWST is vented and how flow is assured
. Basis for Closure:
SUB. meeting: vent piping off high point alarms when air displaces water; piping can then be vented 11
Member Start Date End Date
==
Description:==
Barton 4/8/98 6/18/98 ACRS letter: security design may have adverse affect on safety: increased response time due to required personnel searches Basis for Closure:
SUB.; meeting: W modifed design to allow operators to enter all vital
-areas without leaving the protected area
==
Description:==
Catton 4/8/98 6/17/98 ACRS letter: derived Chi /Q limits mask the effects of any unique site meteorological characteristics Basis for Closure:
SUB. meeting: W commited to include COL applicant requiements in Revision 24 to SSAR
==
Description:==
Kress.
4/8/98 7/7/98 ACRS letter:
document justification of granting credit for' aerosol removal mechanisms in calculating the containment source term Basis for Closure:
-SUB.- meeting: document in FSER that natural aerosol depostion is credited based on a stylized source term and scenario
==
Description:==
Subcommittee 6/15/98 7/7/98 ACRS letter: qualification of passive autocatalytic recombiners should include requirements for timing of exposure and exposure to pyrolysis-products Basis for Closure:
'SUB. meeting: qualification of passive autocatalytic recombiners will be the responsibility of the COL applicant 12
id Member Start Date End Date
==
Description:==
Carroll 6/17/98 7/7/98 W agreed to explain how 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire doors and ventilation dampers prevent the spead of smoke Basis for Closure:
SUB. meeting:
fire doors are not smoke barriers: two fire doors provided between rooms: ventilation flow shifted to reduce spread of smoke
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Description:==
Powers 6/18/98 7/7/98 W agreed to explain the g value used to calculate the production of nitric acid in the containment atmosphere during severe accidents Basis for Closure:
SUB. meeting:
results of staff calculations show small effect on sump PH due to nitric acid: W letter dated July 2, 199 i
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