ML20045D100
| ML20045D100 | |
| Person / Time | |
|---|---|
| Site: | 05200001 |
| Issue date: | 01/04/1993 |
| From: | Michelson C Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2858, NUDOCS 9306250326 | |
| Download: ML20045D100 (24) | |
Text
F DATE ISSUED: 12/22/92 CERTIFIED BY:
Carlyle !;11chelson - 1/4/93 g
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SUMMARY
/ MINUTES OF THE ACRS SUBCOMMITTEE MEETING ON THE ADVANCED BOILING WATER REACTORS (GE)
NOVEMBER 19-20, 1992 BETHESDA, MARYLAND EURPO E The purpose of this meeting was to continue the review of the draf t final safety evaluation report (DFSER) for the GE/ABWR design. The meeting began at 8:30 a.m.
on November 19, 1992 and adjourned at 5:45 p.m.
The meeting was reconvened at 8:30 a.m. on November 20, 1992 and adjourned at 3:30 p.m.
The meeting was held entirely in open session.
No written comments or requests for time to make oral statements were received from members of the public.
Dr. El-Zeftawy was the cognizant staff engineer for this meeting.
The principal attendees were as follows:
ATTENDEES Principal meeting attendees included:
ACRS NRC C.
Michelson, Chairman C.
Poslusny, NRR I.
Catton, Member H.
Pastis, NRR P.
Davis, Member J. Wilson, NRR P.
Shewmon, Member W.
Burton, NRR C.
Wylie, Member H. Walker, NRR R.
Costner, Consultant C. Li, NRR i
M.
El-Zeftawy, Staff T.
Cheng, NRR S.
Lee, NRR GE D. Terao, NRR H. Brammer, NRR J.
Fox J.
Lee, NRR i
J.
Chambers J.
Raval, NRR M. Munson J.
Stewart, NRR B.
Simon J. Guo, NRR l
K.
Gregorie A. Howe, NRR M. Nikahd J. Lyons, NRR O.
Saxena G. Georgiev, NRR F.
Paradiso A. Mendiola, NRR G.
Miller T. Kim, NRR J.
Power T.
Polich, NRR M.
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- 11/19-20/92 ABWR/GE Subete.
Minutes 9
R.
Strong-i C. Christensen OTHERS J. A.
Beard, NUS QiAIRMAN'S OPENING REMARKS In his opening remarks, Mr. Michelson stated that the purpose of this meeting is to examine the resolution of open items and to discuss with the NRC staff and GE representatives the approach taken to close these open items and other related matters.
i GE Presentation Mr. J. Powcr addresse the ACRS concerns that were expressed at the August 19, 1992 ABWR Subcommittee meeting. These concerns and GE's responses are as follows:
Confirm that all welded piping (e.g., no expansion joints l
1.
or bellows) will be used for the reactor service water (RSW) Tnd the reactor building. cooling water (RCW) systems within the control building.
GE Resoonse B
The subject piping is fabricated'and installed as all e
welded piping Major components within the subject systems may have-e flange bolted or welded connections to_ the piping system
ABWR/GE Subcte. 11/19-20/92 Minutes e
No expansion joints or bellows assemblies will be utilized in piping within the control building SSAR Revision e
A statement to the commitments cited above will be included in revised SSAR Section 9.2 2.
Provide additional information relative to (a) the main steam tunnel potential flooding level and its ability to accommodate and contain the resultant Water; (b). water tightness of the structure under flooded' conditions including the pressurization effects; and (c) discuss the potential flooding effects and impacts on the reactor building and the control building GE Response Some confusion has existed relative to the current SSAR e
documentation in the areas of:
main steam tunnel configuration, main steam (MS) and feedwater line (FWL) configuration, main steam tunnel blowvent panels, and main steam tunnel performance characteristics SSAR Revision Plant building drawings will be corrected e
MSL and FWL drawings will be corrected e
Location of blowout panels will be shown e
A new MS tunnel' write-up.may be added e
A flooding' analysis will be added e
3.
Provide additional information relative to the reacher T
11/19-20/92 ADWR/GE Subete.
-4 Minutes service water (RSW) system-isolation capability to preclude excessive control building and/or pump house flooding for a wide variety of RSW pipe breaks, sizes and location GE Response A new safety evaluation was performed for:
RSWS configurations, e
RSWS break spectrum, e
RSWS isolation capabilities, e
flooding inside control building-basement, e
flooding inside pump house building, e
flooding outside both building in pipe chase, and e
alternative enhancements.
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SSAR Revision e
Additional requirements will be added to SSAR-RSWS write-up... air break considerations A change will be necessary relatt re to loss of two RSWS e
divisions Flooding analysis writing will be added e
4.
Confirm that the RSW system will not utilize " lined piping." That is piping with an inside protective liner.
GE Resbonse ABWR Standard design vs. COL design requirements e
$BWR/GE Subcte. 11/19-20/92 Minutes Outside of GE-ABWR standard design No current specific inclusion or exclusion Current RSWS drawing-indicates liner Required liner protection indirectly cited Operating experience recommends internal pipe e
protection SSAR Revision Correct RSWS Figure e
Additional Discussion in COL Section 9.2.15.2.1 e
Additional COL Requirements e
Accommodate Liner Degradation with Safety Evaluation-e 5.
Provide additional information relative to the design basis of the reactor service water system pump house _and the buried yard piping network between the pump house and the control building GE Response ABWR Standard design vs. COL design requirements e
Outside ABWR standard design GE scope is within the control building All portions of RSWS outside control building are COL-site specific aspects Pump house building and yard-buried piping chase structure are not covered in SSAR
\\s.
ABWR/GE Subete. 11/19-20/92 Minutes SSAR Revision A new brief but comprehensive SSAR section will be o
developed and issued 6.
Provide the desi.o basis and safety evaluation requirements rela +. 9
' a the RSW system piping penetration into the control building GE Response Current Standard-COL Interface Requirements-in SSAR e
Current RSWS standard requires that inside and outside equipment be designed to seismic, ASME, quality and safety standards Current control building standard is designed against external flood damage by wall thickness, water stops at construction joints, water tight door and piping penetrations, etc.
SSAR Revision i
e A paragraph relative the subject piping penetration will be added to SSAR Section 9.2.15 l
7.
Provide additional information relative to plant equipment j
rooms structural / barrier walls capabilities.with specific j
emphasis on the reactor
- building, the-secondary
'I containment, the control building and the divisional separation compartments under pipe break, flooding and.
fire conditions.
The information should address delta P integrity retention capabilities, compartment
ABWR/GE Subcte. 11/19-20/92 Minutes pressurization flooding and fire analysis and compartment and quadrant venting / relief techniques.
GE Response e
The secondary containment divisional separation zone loads are confined to two high energy pipe breaks.
Conservative pressurization analysis and technique are used. In addition, reliable venting equipment is used.
The control building barriers are leak-tightness oriented.
SSAR Revision A brief paragraph relative to the structural barrier e
delta P design basis requirements will be added to appropriate SSAR 8.
Provide additional information relative to the use of stacked block wall within the secondary containment structures and compartments. Provide the design. basis and safety evaluation of these temporary structures including i
affects resulting from pipe breaks within these compartments.
GE Response e
Most structural barriers-compartments and equipment room are permanent e
Some semi-permanent structures are used:
Removable shielding walls, equipment hatches, blowout panels
f ABWR/GE Subete. 11/19-20/92
' Minutes i
e Temporary barriers may consist of a
variety of designs -bricks and blocks Subject temporary barriers will be designed to stay in e
place under pressurization events SSAR Revision A paragraph reflecting the above will be added to the e
appropriate SSAR section (e.g.,
compartment pressurization (6.2.3) or missile potentials (3.5.1).
9.
Provide additional specific design basis and evaluation information relative to the reactor
- building, the secondary containment (SC), the control building (CB), and the divisional separation barrier penetrations.
Special emphasis should be directed at the wide variety of barrier penetration types (including piping, cable trays, and HVAC ducts) used.in the ABWR standard design under pipe break; pressurization, flooding and fire conditions. Information 4
should cite integrity assurances and pressure and temperature accommodations.
GE Response ABWR Standard design is unique relative to-past plant e
designs.
Secondary containment - divisional separation quadrant barrier. penetration are of most important and of greatest interest.
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' 11/19-20/92 ABWR/GE Subcte.
14inutes Divisional separation quadrant, house the critical e
mitigation equipment (ECCS).
Divisional separation also provide protective housing for piping penetrations, instrumentation, control and power penetrations, HVAC penetrations and auxiliary service penetrations (e.g., cooling water).
SSAR Revision A set of paragraphs will be added to the appropriate e
SSAR sections relative to the above SC and CB specific penetration design.
10.
Provide additional specific design basis and safety evaluation information relative to the reactor building, the secondary containment, the control building and the divisional separation barrier doors.
Special emphasis should be directed at the wide variety of barrier door closures types (including single and double wide doors, motor-operated
- doors, sliding
- doors, equipment hatches / doors, large vehicle entry. doors, elevator doors and stairwell doors) used in the ABWR standard design under pipe break conditions:
pressurizations, flooding and fire.
Information should cite delta P capabilities, air and water leak-tightness, fire resistance, and closure reliability.
GE Response unique compartmentization &
ABWR Standard design 1
freely uses barrier door
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ABWR/GE Subcte. 11/19-20/92.
Minutes Doors provide ready yet controlled access to modular e
equipment cubicles / areas Ready access enhances plant surveillance,
- test, e
inspection and maintenance operations Minimizes personnel and equipment dose; maximizes ALARA e
initiatives SSAR Plant layout drawings identify most doors e
ABWR will heavily utilize past reactor door operating e
experience insights - reliability, operability, etc.
SSAR Revision e
A table will be added to appropriate SSAR section reflecting the above.
A new paragraph will be added to appropriate SSAR section on barrier door design basis.
11.
Provide additional specific design basis and evaluation information relative to the reactor
- building, the secondary containment, the control building and the
)
divisional separation compartments floors and ceiling l
leaktightness.
Special emphasis rhould be directed at_
floor and ceiling barrier integrity under flood water retention, fire containment, pressurization (delta P), and-accident effects (pipe whip, jet impingement, etc.).
Floor equipment and divisional drain system interconnections should be considered.
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1 ABWR/GE Subcte. 11/19-20/92 Minutes GE Respons_q e
ABWR Standard is a
unique design-horizontal compartmentization and vertical open communication Primary containment.(PC) is a leaktight structure with e
internal leaktight compartments Secondary containment (SC) is a leaktight structure for e
inside PC DBA breaks Secon-lary containment (SC) is not a leaktight structure e
for external DBA breaks e
Reactor Building (RB)--in and of itself--is not a leaktight structure e
RB-Clean
. rooms, major equipment
- rooms, support equipment rooms are not leaktight to environs SC-Divisional separation quadrants are inter-leaktight e
relative to one another SSAR Response A brief paragraph citing selective ceiling and-floor e
leaktightness requirements and considerations will-be added to appropriate SSAR sections 12.
Provide additional specific design' basis-and evaluation information relative to the reactor
- building, the-secondary containment, the control building and the divisional separation compartments HVAC system.
Special j
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I ABWR/GE Subcte. 11/19-20/92 Minutes emphasis should be directed at HVAC isolation valves and f
backflow dampers under a variety of plant disturbance conditions (including DBAs, internal floods, internal fires, radiological releases, environmental pertubations, etc.).
GE Response ABWR Standard design utilizes a unique network of HVAC e
subsystems for various plant conditions e
Reactor building / secondary containment HVAC is different from past plant designs RBVs provides no HVAC to SC e
Under DBA conditions RBVs is isolated and safety equipment get individual / local HVAC subsystem service Selective reactor building safety related rooms receive e
their normal and accident HVAC service from individual divisional HVAC subsystems For breaks inside SC, RBVs is isolated and local HVAC e
subsystems operate as in DBAs SC - is not required I
e SSAR Revision e
Additional information will be incorporated in the current plant ventilation system descriptions.
~ 11/19-20/92 ABWR/GE Subcte.
Minutes 13.
Provide additional information relative to the use of, the location of, the design of and the performance analysis of blowout panel cited throughout the SSAR in safety related structures / compartments.
GE Response Considerable amount of confusion exist relative to SSAR e
blowout panels Blowout panels are being used in a number of safety-e related structure / compartment pressure relief functions Basic operating principles of pressure blowout panels e
is rather simple current analysis models are fairly straight forward and e
accurate e
A variety of physical blowout panel hardwares is available
.SSAR Revision e
Plant layout drawings will be adjusted for design refinements Pressurization tables and figure will adjust for design e
refinements e
Add a new paragraph on main steam tunnel blowdown panels aspects -
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ABWR/GE Subcte. 11/19-20/92 Minutes 14.
Describe in general where remote multiplexing units (RMUs) are utilized and located throughout the plant and specifically determine whether safety essential RMUs are located within the secondary containment structure.
GE Response e
Make extensive use of proven and reliable digital components Recognizes that similar components in past have been e
environmentally sensitive Will continue to use conventional qualified hardwired e
electronics in harsh environmental areas Design will cautiously locate safety-related system e
RMUs in environmentally protected, or e
Will use equipment for data transmission, and activating trip signals in sensitive areas e
Also can use RMUs with non-safety related systems (e.g., feedwater control)
Current SSAR multiplex system writeup identify critical e
signal and control equipment locations Safety-related RMUs are located outside the primary and e
secondary containment boundaries.
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1 ABWR/GE Subcte. 11/19-20/92 Minutes SSAR Revision e
RMUs will not be identified inside PC or SC on plant layout drawings e
Statement to the effect that no essential RMUs are located within the PC or SC boundaries Plant layout drawings will reflect essential and non-e essential RMU locations A new write-up will be provided relative to essential' e
and non-essential RMUs 15.
Provide additional information relative to the plant floor drain systemr, with specific attention to the reactor building, the secondary containment, the _ control building, and the divisional separation areas under normal conditions (equipment and piping-leakage) and under accident - pipe break condition (compartment flooding, pressurization and fire)
GE Response Not part of ABWR standard e
Interface requirements have been provided e
e Reactor building sump collection is shown on ' plant layout drawings Radwaste system transfer interconnections are noted on e
various P & ids l
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i ABWR/GE Subete. 11/19-20/92 Minutes Internal. flooding analysis ignores successful system e
operation SSAR Revision i
e Some additional COL Interface Information will be included in revised Section 9.3.12 16.
Provide additional specific information relative to post accident (DBA) environmental conditions within the reactor.
building, the secondary containment, the control building and within various divisional separation compartments with special emphasis on their effects on safety-related equipment in the affected areas GE Response Significant amount of general information is available e
throughout the SSAR Additionally rather comprehensive / specific discussions e
are also provided Design basis and protective measures for safe shutdown capabilities (SSCs) under DBA's
. Worse environs for SSCs at their locations Break effects both inside/outside containment including system interactions
- breaks, floods,
- fire, e
Internal event evaluation adverse environs
ABWR/GE Subcte. 11/19-20/92 Minutes e
Key assumptions:
Break terminations outside containment, divisional separation, and SSCs and requirements Safety related equipment performances under post-DBA e
SSAR Response Some additional updated information will be added to e
appropriate sections reflecting new insights and inquiry responses 17.
Provide additional specific information relative to the individual-equipment room heat up rates upon loss of room HVAC for reactor building, secondary containment, control building and divisional separation compartments with special emphasis on equipment temperature
- effects, temperature detection and monitoring, structural implications, operator information and system interactions l
GE RESPONSE Basic design philosophy l
e
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RB/SC/ divisional separation; Unique application e
CB/MCR/ equip rooms / basement Current available information sources - extensive SSAR sections i
Traditional concerns - DBA effects Special I&C/ loss of HVAC concerns e
q ABWR/GE Subete. 11/19-20/92 Minutes SSAR REVISION e
No major changes to the current SSAR sections are contemplated for the plant ventilation systems documentation (Section 9.4) nor for the. plant safety analysis (Section.14.0) 18.
Provide a set of RWCUS piping / component layout drawings.
GE RESPONSE e
A preliminary set of detailed RWCUS piping ana component drawings have been forwarded SSAR Revision Appropriate RWCUS SSAR sections will be amended to provide previous comment responses.
e The forwarded drawings will not be added as standard SSAR enclosure documents.
They have been submitted as special information.
URC STAFF PRESENTATION Mr.
C.
- Poslusny, NRR,- responded to the subcommittee member's concerns regarding the open items related to the following DFSER chapters:
Chapter 2 - Site Characteristics Chapter 3 - Design of Structures, Components, Equipment and Systems 1
b' ABWR/GE Subcte. 11/19-20/92 Minutes Chapter 6 - Engineered Safety Features Chapter 8 - Electric Power Systems Chapter 9 - Auxiliary Systems Chapter 14.2 - Initial Plant Test Programs Based on general discussions with the staff and GE representatives the following are concerns and requests from the subcommittee members:
p_r. Catton 3.
The calculational tools used by GE and the staff (COMPARE and SCAM) for sub-compartment behavior yield volume averaged temperature and pressure.
Design limits are given for temperature.
If it is calculated that these limits are approached, they will certainly have been exceeded because thermal stratification is a real physical phenomena. How is this difference resolved? This concern.
applies to environmental qualification requirements as well as drywell and wetwell temperature limits.
2.
Although on the surface the treatment of LOCA loads appears to be satisfactory, many of the important details are missing.
For example, the water slug thickness is
. chosen to be the pool surf ace to top vent thickness.. -What is the basis for this?
According to the
-SER,
" adaptations" of an earlier code was made.
What were the adaptations?
What were the
" hydrodynamic loading assumptions" and why doesn't the staff like them?
3.
The vacuum breakers are now protected from pool swell and fall back.
What does the design look like?
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g ABWR/GE Subcte. 11/19-20/92 C
Minutes 4.
GE did transient calculations using fl/d's for standard fittings.
Were the values corrected for accelerating flows?
5.
The general question of pool thermal mixing needs to be addressed.
How much stratification is a reasonable amount?
Doing low mass flow chugging, how much of the pool acts as a heat sink?
6.
What kind of debris could result from a SLB or other.high energy line break and where will it be carried?
Considertions should be given to the sheet steel insulation and the possibility that flow paths to the suppression pool may get blocked.
7.
High energy line breaks can result in high velocity flow through doorways and other restricted flow areas.
This goes well beyond " jet impingement" and " environmental qualification."
Sheet metal ducting can be damaged.
Cabinets can be damaged by buffeting.
To be properly treated, environmental qualification needs to include flow effects.
Mr. Michelson 1.
Expressed concern regarding the misuse of COL action items.
He stated that the staff refers to design to be completed in the future and-it is not clear how the staff can make a final safety determination with this type of action items left unaddressed.-
2.
Indicated that nothing in 10 CFR Part 52, subpart B recognizes a COL.
He added that the final ABWR safety
r ABWR/GE Subcte. 11/19-20/92 Minutes determination should not be based on COL holder.
Mr. Wylie Commented that there are cases where COL action items are
" promises" of characteristics of a design that must be known to make a final safety determination, especially in Chapter 8,
" Electrical Power Systems."
]ir. Michelson Stated that justification that interf ace requirements can be verified by inspection,
- testing, analysis, and acceptance criteria is required by 10 CFR Part 52.47.
However, such justification is not found in the staff DFSER.
Mr. Carroll Faxed his concerns (general and specific) regarding the staff DFSER.
The general concerns are:
During the 10/21/92-meeting, Mr.
Carroll expressed e
concern that_the staff was misusing the
" COL Action Item" designation in the DFSER.
He : pointed out a number of places where it was being_ used by staff members as a hedge against an incomplete Tier.1 design description, ITAAC and/or Tier 2 material. In his view of Part 52, this is totally unacceptable.
The' staff must make a clean final safety determination solely on I
the basis of the Tier 1 design description, the associated ITAAC(s) and the Tier 2 material.
(The only-exception is the limited number of issue that are being d
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f ABWR/GE Subcte. 11/19-20/92 Minutes treated as DACs or as site-specific interface issues.)
With these exceptions, the " Confirmatory Action Item" designation should be used only for operational phase-(post fuel load) issues.
The acceptance criteria for satisfying these operational phase issues should be clearly spelled out in the FSER.
There is a wide variation in format between chapters.
e Mr. Carroll likes what was done in Chapters 8 and 9, where each section ends with a summary of the Design-Certification Material, Mr. Carroll had trouble working up a lot of enthusiasm e
for reviewing this material given that the ACRS has to do it over again when the final FSER and the completed ITAAC will be received.-
ACTIONS. AGREEMENTS, AND FOLLOW-UP ITEMS
~
1.
The subcommittee members agreed that the staff was not ready to discuss three major chapters:
Chapter 7, on instrumentation and Control; Chapter 18, on Human Factors Engineering; and Chapter 19 on Severe Accidents and PRA.
These chapters are now undergoing rework by the staff and GE.
The staff has not indicated when they will be ready for ACRS' review.
l 2.
The ACRS stand prepared to complete its review whenever the FSER and the associated Design Descriptions, DACs, and the ITAACs are reasonably complete, up to date, and'have been subjected to appropriate quality checks; and the staff and GE are ready to support final meetings.
The quality checks are j
IBWR/GE Subcte. 11/19-20/92
' Minutes essential to the resolution of numerous technical conflicts between the
- SSAR, and
3.
Certain other ACRS review work remains.
The ACRS is proposing to schedule a meeting with the staff when they are ready to discuss Apendix 9A, which is the Fire Hazards Analysis, and Chapter 16 which contains the
~ proposed
. Technical Specifications.
4.
Still remaining for selective review will be the final closure of over 300 open items in the draft FSER; consideration of certain Design Descriptions, DACs, and ITAACs as they reach final development; and a number of requests for additional information from previous ABWR. subcommittee meetings.
5.
Also pending is the ACRS review of the proposed technical resolution of the Unresolved Safety Issues (USIs) and the medium-and high-priority Generic Safety Issues (GSIs) which are technically relevant to the ABWR design.
In addition, there are a number'of miscellaneous SSAR sections which the ABWR subcommittee has not seen for the first time.
FUTURE ACTIONS The ABWR subcommittee chairman is planning to brief the full Committee at the December 9-12,- 1992 ACRS meeting.
Pending the results of such briefing, the subcommittee chairman may. recommend a certain course of action.
In addition, the subcommittee chairman is planning to brief the Commission on December 11, 1992 regarding the status of the ACRS review of the ABWR design.
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i 11/19-20/92 ABWR/GE Subcte.
- 24 Minutes BACKGROUND MATERIAL PROVIDED TO THE SUBCOMMITTEE 1.
DFSER --dated October 5, 1992.
2.
ACRS letter to EDO, dated April 13, 1992.
3.
Note from C. Michelson_to E. Igne, " Items to Include in Future SSAR Revision," dated August 28, 1992 4.
Items from October 21, 1992 Subcoraittee meeting.
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NOTE:
Additional meeting details can be obtained from a
transcript of this meeting available in the NRC Public-Document Room,.2120 L Street, NW,-Washington, DC 20006, (202) 634-3273, or can be purchased from Ann Riley and Associates, Ltd.,
1612 K
- Street, NW, Suite
- 300, Washington, DC 20006, (202) 293-3950.
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