ML20133H198
| ML20133H198 | |
| Person / Time | |
|---|---|
| Site: | 05000447 |
| Issue date: | 03/18/1985 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2261, NUDOCS 8508090230 | |
| Download: ML20133H198 (22) | |
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b DATE ISSUED: MAR. 18, 1985 MINUTES OF THE COMBINED MEETING OF THE ACRS SUBCOMMITTEES ON GESSAR II AND RELIABILITY AND PROBABILISTIC ASSESSMENT DECEMBER 4-5, 1984 LOS ANGELES, CA A ccmbined meeting was held of the ACRS Subcommittees on GESSAR II and Reliability and Probabilistic Assessment at the Hyatt at the Los Angeles Airport, Los Angeles, CA. This was the second in the current series of meetings to review the General Electric Standard Safety Analysis Report to extend the Final Design Approval so that it will be applicable to The meeting continued to discuss deterministic / standard future plants.
review plar iten... as well as questions raised during the October 1984 Subcommittee meeting. The meeting also continued the review of severe accident considerations and the probabilistic risk assessment performed in connection with the GESSAR II design. Notice of this meeting was published in the Federal Register on Friday, November 30, 1984 (Attachment A). The schedule of items covered at this meeting is in Attachment C is a list of the meeting handouts which are Attachment B.
in the ACRS office files. Portions of the meeting were closed which dealt with Proprietary information, FOIA Exemption (b)4. Mr. Richard Major was the cognizant ACRS Staff member present for the meeting.
Attendees.
ACRS D. Okrent, Chairman A. Camp, Consultant J. Ebersole, Member I. Catton, Consultant H. Etherington, Member M. First, Consultant C. Michelson, Member A. Payne, Consultant e
D. Ward, Member R. Savio. ACRS Staff m@
C. Wylie, Member R. Major, ACRS Staff S
RDA NRC g
g Im J. Fox W. Kastenberg J. Wilson na D. Hawkins P. Hamond B. Hardin SE K. Holtzclaw J. Dooley J. Read C. Thomas 8
J. Quirk D. Scaletti
@gg P. Knecht J. Holonich ma.ed R. Villa H. Rubin J. Maxwell R. Frahm W. Gilbert G. Sherwood 3s. c Asn onIGINAL A. Postima, Consultant Osa W7 certified 30
GESSAR II/RPA 2
Dec. 4-5, 1984 Meeting NRC Staff Introduction - C. Thomas /D. Scaletti, NRC The Staff reported the Commission had yet to vote on the severe accident policy statement.
It was noted that the severe accident policy statement would now' allow an applicant the option of proceeding to design certification through the rulemakinj process, or under the change stopping at the finish of Staff and ACRS review with a forward referencible design. Should an applicant choose not to carry a revfew through to certification 1) the design is subject to litigation in individual licensing proceedings and 2) the final design approval would be good for less time than the design certification.
Initial thinking is that a design certification would be good for ten years and the final design approval good for five years.
As currently drafted, the Severe Accident Policy Statement, if approved, woul'd allow the GESSAR II design to become immediately forward referencible. Although a new construction permit applicant could reference GESSAR II, a new CP could not be issued until the end of the Staff's and ACRS' review.
Presentation by R&D Associates (RDA)
R&D Associates (RDA), consultants to the NRC Staff, discussed the results of their studies on mitigation. Their reports are aimed at developing a coherent approach for assessing the practicality, cost and value/ impact of a mitigation program for rendering a containment relatively resistant to severe core-melt accidents.
Among the Containment types studird by RDA was the Mark III. Mitigation was defined as those actions, devices, or systems intended to reduce, ameliorate, or remove the consequences to the public of a severe accident or remove the consequences to the public of a severe accident wherein the core of a reactor is degraded or melted.
Inp/actice,this
GESSAR II/RPA 3
Dec. 4-5, 1984 Meeting means keeping the containment from failing.
For the mitigation studies RDA assumes mitigation must be complete, accident phenomena must reach a determinate end state, operator action is not available, and electric power is not available.
It was noted that cost / benefit predictions are based on consequence estimates which contain large uncertainties. A difference of nearly three orders of magnitude exists between GE's estimates of consequences (person-rem) and the Staff's. This leads to large uncertainty in the benefit of mitigation strategies.
RDA representatives observed that global hydrogen combustion and detonation were the largest contributors to risk through the containment failure mode.
RDA examined mitigation devices that could be incorporated into a Mark III pressure suppression containment design.
In all their evaluations, RDA assumes the mitigation equipment used is highgrade industrial quality, not nuclear-safety-grade. Systems considered include redundant dual heat-removal systems which use diesel driven pumps to remove water from the suppression pool, cool it, filter it, and spray it back into the containment. A dedicated heat removal plant was considered. This Pressure system would be able to handle decay heat after one hour.
relief valves and condenser / filter were examined as means to mitigate an ATWS event. Also explored was a Dry Crucible Core Debris Retention and Cooling device. RDA concluded that for conventional pressure suppression containments the least expensive way to handle hydrogen generation is post-accident inerting with nitrogen.
This RDA introduced the concept of an unpressurized containment.
concept, based on a Mark III' pressure suppression containment, is aimed The at confining fission products released during a severe accident.
containment is an enclosure rather than a pressure vessel. This system
o GESSAR II/RPA 4
Dec. 4-5, 1984 Meeting s
The employs a chilled filter that operates passively after an accident.
filter, chilled by a refrigeration plant, uses 1000 tons of crushed rock and 50 tons of charcoal. This concept also uses a heat removal system that cools water from the !.uppression pool and returns it to a water jacket that surrounds a dry crucible for core debris and to containment The containment is equipped with hydrogen igniters. The sprays.
It is chilled filter will trap completely Kr. Xe, I, and particulates.
claimed the low-pressure containment costs less to build and operate than a conventional Mark III containment.
Work underway on the accident radiological source-term by RDA and BNL may shed additional light on uncertainties between cost / benefit The new source term is expected to be lower; this will evaluations.
increase the current cost /berefit ratios. Dr. Okrent cautioned that the real cost associated with the interdiction of a severe accident should be given serious consideration, that the $1000/ person-rem criterion for safety improvements may not reflect the cost incurred for a severe accident recovery project.
It is uncertain what residual dose the public would find acceptable following recovery from a severe accident.
This uncertainty could account for a large increase in the cost of interdiction.
Dr. Okrent stressed that a thorough understanding of methods to improve safety would be required before the Subcommittee's review could be He concluded, including both mitigation and prevention strategies.
noted the differences in cost estimates between the work presented by RDA and work done at Sandia which concluded costs would be substantially higher. The reasons for the differences between these two NRC Staff-sponsored studies should be explored. The impr.:t of seismic considerations remains an unknown at this point.
Mr. Ward commented that using industrial quality mitigation systems to j
deal with an event of very low probability could lead to the argu n nt u
GESSAR II/RPA 5
Dec. 4-5, 1984 Meeting that such measures may not be worthwhile. The reliability of such measures may be lost in the uncertainty of the probability of the event occurring in the first place.
Dr. Okrent suggested a thorough study of possible filter bypass paths associated with the RDA concept.
General Electric Response to RDA Presentation-J. Quirk, K. Holtzclaw, GE Mr. Quirk, GE commented that the systems proposed as mitigation devices by RDA had many of the same weaknesses as the systems assumed to fail.
He also stressed the basic difference between a vented confinement for processing fission products during low probability events and the philosophy of containing fission' products.
It was explained the suppressionpoolremovesfissiondroductsinbothconcepts.
Mr. Holtzclaw, GE, discussed the RDA report.
It was felt the RDA risk basis was incorrect. Cost-benefit predictions should be based on best-estimate, not upper-bound assumptions. The point was made that containment function--not integrity--is important to risk. The GE GE program strives for fission product retention in multiple barriers.
also felt the costs of improvements used by RDA were unrealistically The fact that nuclear safety grade equipment is not assumed by RDA low.
must also be factored into consideration. These comments were based on a preliminary review of the recent RDA results. GE plans a more detailed examination.
An update on pool scrubbing was presented to the subcommittee.
Suppression poo! scrubbing is a process by which fission products, released as particulates during a severe accident, are passed through the suppression pool and contained in the pool water. The particulates j
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Dec. 4-5, 1984 Meeting o
enter the pool in a noncondensable gas-steam mixture. Pool scrubbing is the action by which the particulates move from the gas phase to the gas-liquid interface, where they are trapped and contained by the liquid. A scrubbing efficiency is defined as a decontamination factor which is the ratio of the mass of fission products introduced into the pool divided by the mass of fission products released from the pool surface.
General Electric described experimental programs devised to quantify the pool scrubbing decontamination factors.
Scrubbing tests were performed on small-scale models; hydrodynamic penomena were performed on medium scale apparatus. Currently EPRI is conducting a two-to three-year test program on suppression pool scrubbing at Battelle Columbus Laboratories.
The tests by EPRI will be integral tests where the mass transfer and hydrodynamic phenomena are combined as opposed to GE's separate effects testing. GE feels that the EPRI testing is confirming GE's own test results. The EPRI test program will continue beyond mid-1985.
Experiments also varied the size of particulates to determine the effect of particulate size on scrubbing efficiency.
It is believed that a 5-micron aerodynamic mass median diameter particle distribution would be present during a core-relt accident. Tests were performed on smaller (a l micron) particles and it was found that it is more difficult to scrub these than the larger 5-micron particles that, it is felt, are more representative of melted core aerosols. Decontamination Factors (DFs) observed for what is t,elieved to be hard-to-scrub particulates were on the order of several thousand. GE concludes DFs are substantial even under pessimistic conditions. GE predicts a lower bound DF of 1000 for the quencher entrance to the pool and a DF of 100 for the vent GE felt the biggest areas of uncertainty in the calculated entrance.
Dh tre in tne areas cf particle size effect and the potential for pool bypass.
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GESSAR II/RPA 7
Dec. 4-5, 1984 Meetir.g
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ACRS consultant M. First raised a concern about the lack of overlap between the GE pool scrubbing tests and those performed by EPRI. Mr.
Quirk of GE felt if questions over the validity of GE's tests were raised by the EPRI work GE could run more tests to validate their model or investigate other dose reduction mechanisms.
The Subcommittee questioned GE on the effects fission product heating
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would have on the pool's ability to effectively scrub. The question centers on whether fission products distributed uniformly through the pool could heat it to above the saturation temperature and what effect this would have on further scrubbing.
Mr. Michelson asked if a Tech Spec. limit of 170*F on the suppression pool water terrperature was made due to the chance of steam passing thrcugh the pool at this temperature without condensing. Could this steam bypass have an effect on decontamination factors? GE agreed to look into this issue.
Two hydrodynamic phenomena affect scrubbing: gas transit time and bubble size in the pool. Hydrodynamic modeling and testing have shown that large bubbles introduced from a sparger break up rapidly to small stable bubbles that rise through the pool at a given velocity which determines how long the fission products can be scrubbed from the pool.
GE recognizes Freude scaling (since gravity and the fluid-free surface play an essential role) as the key effect in matching experiments and determining how fast bubbles get through the pool and their approximate size.
Dr. Okrent requested a copy of a report prepared by Sandia National trboratories that deals with the usefulness of filtered, vented et-4.1ments for Mark I containments.
Indications are that the report h% 3:en completed. The Staff agreed to check into the reports' availability.
8 Dec. 4-5, 1984 Meeting GESSARj!I/RPA Evaluation of Proposed Desion Modifications - Containment Analysis Potential Suppression Pool Bypass Paths - D. Knecht, GE The subcommittee went into closed session to discuss proprietary material related to the evaluation of proposed design modifications and a Containment Analysis of potential suppression pool bypass paths.
GE looked at over 70 design modifications suggested by the NRC Staff.
GE determined the cost / benefit ratios they believed were appropriate to come to a conclusion as to what design modifications may or may not have application to the GESSAR design.
GE used an engineering economics approach when considering design modifications for a hypothetical accident. Capital costs of improvements are compared with the present value of risk avoidance Risk avoidance costs are the probability an accident will occur costs.
tires the accident cost.
The subcommittee Questioned whether or not it is appropriate to discount health effects in a cost / benefit analysis.
It was suggested the Staff discuss this topic with the Commission.
In GE's cost / benefit analysis no potential design modifications were found to have a cost /berefit ratio less than one.
No modifications were justified on a cost / benefit basis. However, it was concluded that the ultimate plant protection system (UPPS) alone was a reasonable addition to make to the design.
It has the capability to respond in a variety of With situations by providing a source of core cooling water.
diesel-powered pumps and manual valves, UPPS can provide core cooling during station blackout by depressuring the reactor cooling system using air-operated valves and providing cooling water.
GESSAR II/RPA 9
Dec. 4-5, 1984 Meeting The subcommittee expressed some concern that improvements that cost more than $25,000 are not cost beneficial and yet operational occurrences such as turbine or generator failure that occur with some frequency cost orders of magnitude more. The reason given for the low cost required to make modifications cost beneficial was the fact that the events being addressed are very low frequency events. The subcommittee noted that differences between GE's cost / benefit analysis and those performed by RDA would be explored at future meetings.
Results of a suppression pool bypass study were presented.
It was concluded that the risk of radioactive releases from pool pathways is much greater than the risk from bypass pathways. The subcommittee cautioned that actual experience has shown that bypass paths can exist.
Examples such as missing caps on drywell penetrations and open plant-exhaust valves were mentioned.
It was stressed that actual operating experience should be factored into consideration in a realistic fashion.
't Mr. Michelson asked GE for documer.tation that showed piping lines leading from the containment to the outside environment were equipped with isolation valves that have been specified and tested to ensure they are capable of closing under blowdown conditions. The effects of valve aging were also raised as a concern. The reactor water cleanup system was mentioned as a specific example of this concern.
The subcommittee requested that the NRC Staff identify those questions and answers that deal with the ability of containment seals (such as around equipment personnel hatches and electrical penetrations) to survive conditions beyond the design basis accident.
GESSAR II/RPA 10 Dec. 4-5, 1984 Meeting 1
December 5, 1985 (Second Day)
Ultimate Safety Shutdown System - J. Quirk, GE Mr. Quirk, GE, presented a discussion on the proposed Ultimate Safety Shutdown System (UPPS). As in previous discussions, he noted the UPPS has three functions.
First, it is able to depressurize the reactor.
Secondly, it can provide makeup water to the reactor; and the third function is to remove decay heat. These functions are accomplished without plant AC or DC power. Depressurization is accomplished using Coolant air operated valves that are actuated from a stored air source.
makeup can be provided using diesel-driven fire protection system pumps or a fire truck.
Decay heat can be removed by venting the containment and steaming to the atmosphere, which is a passive method of removing decay heat.
GE believes the UPPS is orders of magnitude more cost effective than a hydrogen control system.
Dr. Okrent requested thet GE study the UPPS from the point of view of its initiating or exacerbating an off-normal situation. Could the system provide a weakness in the plant design that could be exploited by a ma:icious individual? An evaluation of the system's pros and cons should be made.
Mr. Ward requested GE to elaborate on the contribution to risk indicated by the PRA, from events initiated by inadvertent depressurization of the reactor coolant system. Could the UPPS lead to such an inadvertent depressurization?
Currently GE is proposing a commercial grade UPPS. GE would consider proposing a safety grade UPPS if they are given an incentive to do so, A
such as removing the commitment to install a hydrogen control system.
safety grade UPPS would be designed to seismic standards and may be bunkered as a safeguards precaution.
GESSAR II/RPA 11 Dec. 4-5, 1984 Meeting Mr. Etherington felt that class one components should not be considered He noted perfect systems when evaluating their contribution to risk.
that Appendix G of ASME Section III does require the consideration of cracks in components during a fracture mechanics analysis. He felt the Staff should have some criterion which takes account of less than perfect primary system components.
Severe Accident NI/ BOP Interfaces - J. Fox, GE Mr. Fox of GE discussed severe accident nuclear island / balance of plant It was stated all interfaces are treated as severe accident interfaces.
InterfaceitemsweredescribedasBOPdependent(suchas interfaces.
the turbine); equipment-vendor dependent; applicant dependent (procedural) and site dependent. Some interface items are classified as deferred; these items for commercial reasons will be specified later.
Mr. Michelson requested GE to discuss the consequences of insulating material in the drywell and wetwell areas at a future meeting.
Regarding PRA interfaces an applicant must demonstrate in his FSAR that the 50P design is consistent with PRA interfaces before applying PRA results, or demonstrate inconsistencies have a negligible impact on overall public risk.
In discussing the threat from an external flood, Dr. Okrent questioned whether or not the interface information provided to an applicant who purchases GESSAR II would instruct him to not only calculate the probable maximum flood (PMF) but also evaluate the frequency of the maximum probable flood. Dr. Okrent suggested that the Staff and GE consider whether or not an applicant should consider the chance of exceeding the PMF and decide if it is unacceptably large.
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GESSAR II/RPA
_12 Dec. 4-5, 1984 Meeting Concerning interface procedures and implementation Mr. Fox noted GE has developed a balance of plant interface control specification. This-document is used to designate all interface requirements and all reporting specifications.
Mr. Michelson requested that GE address interface controls over the design of the service water system. Assurance was sought that.such an important system was under adequate control by the design organization.
4 Mr. Quirk continued from previous meetings a discussion of design changes. He described control room human factors design, scram discharge volume improvements, and ATWS improvements.
9 Desion Changes J. Quirk, GE 1)
The control room is a solid state device with important instruments and controls easily accessible.
It includes an emergency response system which provides safety parameter display capability for bo'th.nsintenance and operation.
2)
The scram discharge volvme now employs a direct water level measurement. The level instrumentation is diverse. There are redundant vent and drain valves which preclude leakage as a result of a single failure. The Mark III containment allows any inventory released from a postulated SDV break to enter the suppression pool.
3)
Modificairons as a result of ATWS censiderations include an alternate rod insertion system, recirculation pump trips and an automatic 86 GPM standby liquid control system.
1 GESSAR II, Design Considerations Reducing Sabotage Risk - W. Gilbert, GE NOTE: The Subcommittee met in a closed Proprietary session to discuss safeguards issues:
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s GESSAR II/RPA 13 Dec. 4-5, 1984 Meeting The Subcommittee discussed the general approach taken by General Electric for sabotage protection.
The theory behind compartmentalization, separation, redundancy, and access control were reviewed. The purpose of this session was to develop topics for a more detailed discussion of safeguards at a future meeting to be held at 4
Sandia National Laboratory.
Response to ACRS Questions from October 18-19, 1984 Subcommittee Meeting - K. Holtzclaw, GE The Subcommittee discussed in open session a number of carryover items from previous meetings. Some of the responses and additional questions were:
The Staff noted one area of difficulty in the GESSAR II review was the lack of a final policy statement on severe accidents from the Commission.
Regarding generic issues, the Staff has no requirement to consider issues before they are prioritized.
GE noted that they had at the i
Staff's reauest considered some issues that were not previously prioritized. As items are prioritized, the staff said, they will be considered in the GESSAR design until a reasnnable cutoff date.
GE uses a CO fire suppression system in portions of the GESSAR II 2
design.
The design basis assumes all equipment in a specific fire area is destroyed and assures the plant can be maintained safely.
GE was questioned on the seismic fragility of various components in the fire protection system. GE agreed to supply answers regarding the fragility of fire protection equipment at a future meeting.
GE used over 300 three-hour rated fire dampers in their nuclear islar.d design. Where it was impractical or created an adverse
GESSAR II/RPA 14 Dec. 4-5, 1984 Meeting situation the equivalent of a three-hour barrier (i.e., ducts rated forthreehoursoffirecontait. ment)wereused.
The possibility of multiple fires, such as those that could be postulated following an earthquake, were not considered in the GESSAR II design.
The subcommittee inquired whether or not GE was trying to reduce the reactor trip challenge frequency, especially by using coincidence trip logic on the feedwater and turbine trip systems.
j GE noted this was outside the nuclear island scope and would be the utility's decision.
It was noted the reactor water cleanup system valves can isolate under LOCA conditions. Tests will verify this. The plant design can tolerate the 30 seconds worth of blowdown prior to valve closure.
RHR pumps have not been designed to handle large amounts of entrained air; however, pumps take suction at least five feet away GE from drywell and quencher vents to preclude air entrainment.
also felt much of the entrained air would clear the pool prior to pump operation in a large LOCA sequence.
In response to questions from Dr. Okrent, GE agreed to investigate further the effect of small well-mixed air bubbles on RHR pump performance.
Mr. Michelson inquired whether or not this scenario raises concerns on Mark I plants.
Regarding the consequences of the failure of the first RHR valve outboard of the suppression pool, GE noted the valve is in a 1
watertight room designed for the static and dynamic loads of the flood resulting from this valve failure scenario.
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GESSAR II/RPA 15 Dec. 4-5, 1984 Meeting The Subcommittee questioned whether cyclone se'parators on pumps can concentrate contaminates lighter in density than water and threaten pump seals. GE believes that particles with a specific gravity less than one would float on the top of the pool and not be drawn Should into the pump suction and ultimately into the separator.
some light particles be drawn into the separator, they are not expected to be abrasive and cause damage to the pump seals.
Mr. Ebersole noted that cyclone separators may have been removed on some plants because of their contaminate concentrating potential.
The effects of fiberous insulation and paint chips should be studied.
The safety implications of control systems remain one of the ten outstanding issues in the Staff's review of GESSAR II. This item, according to the severe accident policy statement, must be resolved on the GESSAR II design.
Systems interaction will become an interface requirement for a utility applicant.
Regarding consideration of mult!ple breaks of nonseismically qualified piping during an earthquake, GE noted that essential safety systems are seismically qualified. Nonseismic piping that could cause flooding is analyzed and designed as though it were seismically qualified, but without the quality assurance documentation.
GE noted that the non-safety-grade chilled water system and non-safety-grade drywell chilled water system and safety-grade control building chilled water system were reviewed in accordance with SRP section 9.2.2.
Details of review strategy and materials considerations were requested for a future meeting.
i GESSAR II/RPA 16 Dec. 4-5, 1984 Meeting i
Regarding whether or not PRA methods have been used to identify a chain of events leading to a large water hammer, the Staff noted this subject has been addressed primarily by an experienced-based assessment. GE agreed to provide an assessment of the water hammer potential of the core spray system.
GE agreed to research the water hammer potential of a pump start logic control and sequencing procedure for starting a pump with an open discharge. Henry Jones of TVA has researched this problem.
It was suggested GE contact him and ask for a copy of a report he prepared on this subject. Dr. Okrent requested a copy of this report as well.
Future Meetinas:
The next meeting of the GESSAR II/RPA Subcommittee is scheduled for February 14-15, 1985 in Los Angeles, CA. The principal discussion topic will be seismic risk.
NOTE: A transcript of the open portion of the meeting is on file at the NRC Public Document Room at 1717 H St., N.W., Washington, DC, or can be obtained at cost from Ace-Federal Reporters Inc., 444 N. Capitol St.,
Washington, DC 20001 [ Telephone (202) 347-3700). A transcript of the closed portions of the meeting is on file at the ACRS office.
4
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30, 1984 / Notices
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Fed;r:1 R gist:r / Vcl. 49, N2. 232 / Friday, N:vember m 33 V
' cssur:nce in the design and construction ACRS m:etings cuy be cdjust:d by the W:dn:sday, Dec:mber 5,1964-4.30 c.m. until the conclusion of business Chairm:n as n:c ss:ry 12 facillt:te the nie will be the second in the current cf nuclear power plants, steam conduct of the meeting. persona generator overfill in nuclear facilities, planning to attend should check with the series of meetings to review the Gene ACKS activities, and ACRS procedures.
ACRS Executive Director if such Electric Standard Safety Analysis Portions of this sessicn will be closed ce necessary to discuss matters that rescheduling would result in major Repo-t to extend the Final Design Approval so that it will be applicable to relate to the internal persennel rules and inconvenience.
I have determined in accordance with future plants. Items carried over from practices of the agency and information subsection 10(d) Pub. L 92-463 that it is the October 1984 meeting will be th2 r:! ease of which would represent an necessary to close portions of this considered. The meeting will also focus unw:.rranted invasion of personal meeting as noted abose to discuss on the CESSAR 11 treatment of severs L W p.m,-240 p m.:ACRS Reports to information related solely to the internal accidents and the Probabilistic Risk pnvacy.
NRC(Open)-ne memben will discuss personnel rules and practices of the Assessment performed in connection agency (5 U.S C. 55:b(c)(2)), Safeguards with the GESSAR 11 design.
o proposed report to the NRC regarding the use of Designated Representatises Information which addresses details of Oral statements may be presented by cs a Q A measure in the des:gn and the applicant's security measures (5 members of the public with concurrence -
manufacture of nuclear power plant U.S.C. 55:b(c)(3). Proprietary of the Subcommittee Chairman; written components and systems.
Information (5 U S C. 552b(c)(4)),
statements will be accepted and made 2mp.m -2 45 p.m.:Actisities of ACRS information provided in confidence by a available to the Coramittee. Recordings Members (Open)-Members of the foreign source (5 U.S C. 55:b(c)(4).
will be permitted only during those Committee will report on matters information the release of which wouldportions of the meeting when a discussed during a recent technical represent an unwarranted invasion of transcript is befrg kept, and questions cxchange meeting with representatises personal privacy (5 U S.C. 552b(c)(6),
may be asked only by members of the cf J:panese nuclear mastry, nuclear and information the premature release Subcommittee. Its consultanta, and Staff.
development. and regulatory bodies.
cf which would be taely to significantly Persons desiring to make oral Portions of tbs sess en willbe closed frustrate implementation of proposed to dacuss information provided in agency action (5 U.S C. 55:b(c)(9)(B)).
statements should notify the ACRS staff confidence by a foreign source.
Further information regarding topics member named below as far in advance 245p m -J JJp m.: ACRS Reports to to be discussed. whether the meeting as practicable so that appropriate has been cancelled or rescheduled, the arrangements can be made, f
[p d
ia oms 6 U" IN I" NRC regarding matters considered fpp yn}, f, p),,"n era statern muung, the Subcommmu, almae to during th s meeting and generic issues and the time ellotted can be obtained by any of its consultants who may be cpplicable to the NRC regulatory a prepaid telephone call to the ACRS Present. will exchange preliminary i
Process.
E.xecutiv e Director. Mr. Raymond F.
views regarding matters to be Portions will be closed as necessary Fraley (telephm 202/63M265),
considered during the balance of the to discuss Proprietary and Safeguards between 815 a m. and 5 00 p.m. e.s.t.
Information related to the matters being Dated. November 27,1964 g
ggg discus, ed and information related solely t3 the mternal petsonnel rules and John C. Hoyle, Presentations by and hold discussions s
Ads isary committee Management officer.
with representatives of the General practices of the agency.
Electric Company, NRC Staff, their Procedures for the conduct of and
[*y 7 **8**l consultants. and other interested participationin ACRS meetings were published in the Federal Register on
/
Persons regarding this review.
October 3,1964 (49 FR 193). In
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Further information regarding topica accordance with these procedures. oral y/
Advisory Committee on Reactor to be discussed, whether the meeting or written statements may be presented Safeguards; Subcommittee on Gessar has been cance!!ed or rescheduled,the by members of the public, recordings 11 and Reliability and Probabilistic Chairman's ruling on requests for the 1
will be permitted only durir.g those Assessment; Meeting opportunity to present oral statements portions of the meeting when a The ACRS Subcomm.ttees on and the time a!!otted therefore can be i
transcript is being kept, and questions GESSAR 11 and Reliability and obtained by a prepaid telephone callto may be aslied orJy by members of the probabilistic Assessment will hold a g
g Commit. tee, its consultants, and S'sff.
Mad Mabr Wm 20@4 at t at esAng1 s between 815 a m. and 5.00 p.m e.s t.
ouldn$t y$e ACRS Airport. 8:25 West Century Blvd., Los Persons planning to attend this meeting tate to Executive Director as far in advance as Angeles. CA. Notice of this meeting was are urged to contact the above named practicable so that appropriate published Wednesday. November 14, individual one or two days before the crrangements can be made to allow the 1964 (49 FR 45083).
scheduled meeting to be advised of any necessary tirne daring the meeting for
. The rnecting will be open to public changes in schedule, etc,which may duch statements.Use of still, motion attendance ercept those portions that have occurred.
picture and television cameras during may be closed to discuss proprietary this meeting may be limited to selected information regarding the General Da ted. November 26,1964.
portions of the meeting as determined Electric Standard Safety Analysts Morton W. tJberkin.
. by the Chairman.Information regarding Report.
g,,
gg,g the time to be set aside for this purpose The agenda for the subject meeting g
may be obtained by a prepaid telephone shall be as follows:
IF" D" '**8 * "-***
- 88 **I s
call to the ACRS Executive Director, R.F. Fraley, prior to the meeting In view Tuesday. December 4,1984-8.30 a.m.
of the possibiltiy that the schedule for
, untilthe conclusion of business omeo com re ei es ATTACHMENT. A
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/, trMWiww y y PROPOSED TOPICS GESSAR II - FDA REVIEW DECEMBER 4-5, 1984 THE HYATT AT LOS ANGELES AIRPORT LOS ANGELES, CA (Attempttokeepfirstdayopen)
Tuesday, December 4, 1984:
10 min.
1 8:30 AM
- 1. Chairman's Introduction I hr. 15 mins.
- 3. GE Discussion of Cost / Benefit Considerations 9:55 AM of Potential Safety Improvements and Comments of RDA Analysis 10 mins.
BREAX 10:40 AM 2 hrs.
- a. Introduction / discussion of pool scrubbing
- b. Critical fission products for which control is essential
- c. Uniformity of airborne fission products -
justification
- d. Scaling effects of experiments
- e. Effects of independently applying removal mechanisms in analysis vs. air overall removal rate to be anticipated
- f. Additicral research that has been examined I hr.
LUNCH 12:50 PM e
I hr.
- 5. Discussion of Containment Analysis with 1:50 PM Discussien of Potential Suppression Pool Bypass Paths 1 hr.
- 6. Discussion of UPPS 2:50 PM
- a. Commercial vs. safety grade UPPS design
- b. Additional benefits to be gained from the use of a hydrogen ignition system 10 mins.
3:50 PM *********
BREAK 45 mins,
- 7. Interface Requirements 4:00 PM
- s. GESSAR II controls fer maintaining interface compatibility
- b. Severe Accident NI/ BOP Interfaces 30 mins,
- 8. Potential impact of proposed Safety Goals 4:45 PM
- a. Proposed Consission Safety Goals l
- b. Safety Goals (ALARA) contaiment per-formance goals ATTACm'EtTI B
- c. How to treat uncertainties prudently
2
~
30 mins.
- 9. Discussion of New Design features / Philosophy 5:15 PM Behind Design Changes
- a. Control Room Human Factors
- b. ATWS Improvements
- c. Scram Discharge Volume RECESS Until 8:30 AM on December 5, 1984 5:45 PM i
Wednesday, December 5, 1984 10 mins.
8:30 AM 10. Executive Session
- a. Discuss Schedule
- b. Objectives 21 hrs.
- a. Questions and answers on Staff decisions prior to the final SER position
- b. Further Staff /GE considerations of unprioritized generic issues
- c. Consequer.ces of inadvertent trip of fire protection system en plant equipment
- d. Development of instrumentation and controls to reduce the number of spurious trips
- c. Seismic design basis for the Reactor Water Cleanup System? Effect of a single pipe break? Can valves isolate the system under LOCA conditions?
- f. Have RHR pumps been designed to cope with large quantities of entrained air? Pump suction optimally located?
- g. Consequences of the failure of the first RHR valve outboard of the suppression pool 10 mins.
BREAK 10:30 AM
- 1. A-43, Containment Emergency Sump Reliability -
can cyclone separators. concentrate contaminates 1
and threaten pump seals?
i B-2 i
^
3
- j. A-43, Paint Qualifications for containment surfaces, design life of paint and qualification of n,ultiple layers
- k. A-47 Safety Implications of Control Systems, impact of control system reliability on safety for BWRs - Implications of current work?
- 1. A-17, Systems Interactions - What has been done for GESSAR II, what will be done for the utility-supplied portions, and how might addtional requirements impact?
- m. B-6, Loads. Load Combinations, and Stress Limits -
Consideration of multiple breaks of non-seismically qualified pipes
- n. A discussion of events beyond DBA involving the Spent Fuel Pool - Is fuel pool cooling equipment seismically cualified? How is the chilled water system reviewed?
- o. Have probabilistic risk assessment nethods been used to identify and categorize on a risk basis the chains of events that could lead to a large water hammer?
- p. Description of pump start logic control and valve sequencing procedures for starting with an cpen discharge 45 mins.
11:20 AM 12. Discussion as to what approach has been used in the GESSAR 11 design for reducing the threat of sabotage (the purpose will be to develop topics for a more in-depthclosedsession)
I hr.
LUNCH 12:00 N Assessment of PPA limitations and uncertainties 1:00 PM 2 hrs.
- a. Discussion of PRA scope-to include a discussion of the treatment of plant specific interfaces and:
- 1. key assurptions and approximations
- 11. key accident initiators iii. possibly relevant phenomena not included
- b. Systematic a'nd comprehensive list and discussion of omissions, uncertainties, and limitations of PRA results 1-3
4
- c. Adequacy of systems analysis (to include discussions on the use of generic vs. component specific data, performance of system components unter accident conditions,)and the use of systems interaction information
- d. Treatment of Human Errors
- e. Core melt source term and source term reduction models
- f. Severe Accident and Containment Performance models 2:30 PM NRC Approach to Review of Possible Design Improvements 10 mins.
BREAK 3:00 PM I hr.
3:10 PM Discussion of Report by ACRS Consultants Regarding the GESSAR II PRA 4:10 PM Briefly Preview: External Event Analysis Seismic 35 mins.
Margins (NRCStaff) 15 mins.
4:45 PM ACRS Comments and Discussion of Agenda for Future Subcommittee Meetings 5:00 PM ADJOURN N
l I
S E-4 9
c c.
n-
- -. -. - - - ~, -.
4 ATTACHMENT C LIST OF SLIDES COMBINED MEETING OF THE ACRS SUBCOMMITTEES ON GESSAR II AND RELIABILITY AND PROBABILISTIC ASSESSMENT DECEMBER 4-5, 1984 LOS ANGELES, CA December 4, 1984:
Sign-In sheets 1.
Slides used by R&D Associates - 32 slides 2.
GE Discussion of RDA Report - 3 slides 3.
Pool Scrubbing Issues and Update - 13 slides 4.
Proprietary Slides: Evaluation of Proposed Design Modifications -
Il slides 5.
Proprietary Slides - Containment Analysis Potential Suppression Pool Bypass Paths - 9 slides December 5, 19P.4:
Sign-In sheets 1.
Ultinate Safety Shutdown System - 4 slides 2.
Severe Accident N!/ BOP Interface - 13 slides 3.
Design Changes - 5 slides 4
GESSAR II, Design Considerations Reducing Sabotage Risk-Marked
" Safeguards Information" - Proprietary - 41 slides ATTACHMENT C a