ML20151P556
| ML20151P556 | |
| Person / Time | |
|---|---|
| Site: | 05000447 |
| Issue date: | 11/08/1985 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2351, NUDOCS 8601230339 | |
| Download: ML20151P556 (18) | |
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SUMMARY
/ MINUTES OF THE SEPTEMBER 11, 1985 MEETING OF THE ACRS GESSAR II SUBCOMMITTEE WASHINGTON, D. C.
A meeting was held by the ACRS GESSAR II Subcomittee on September 11, 1985 at 1717 H St. NW., Washington, D. C. in Room 1167. The purpose of this meeting was to continue the Subcomittee's review of GESSAR II for a Final Design Approval applicable to future plants.
Selected Items from SSER #4 as well as other outstanding ACRS review items were dis-cussed.
Portions of the meeting that dealt with plant security and General Electric Company (GE) proprietary information were closed to public attendance.
Notice of this meeting was published in the Federal Register on Thursday, August 22,1985(AttachmentA). The meeting schedule is Attachment B.
Richard Major was the cognizant staff member for the meeting.
Participants ACRS NRC Staff GE D. Okrent, Chairman D. Scaletti P. D. Kne::ht J. Mark, Member R. Frahm N. Pfeffbrlen C. Wylie, Member B. Hardin D. Hankins C. Michelson, Member R. Hernan D. Foreman J. Ebersole, Member M. Rubin K. Holtzlaw R. Major, Staff M. Spangler R. Villa W. Pratt, Consultant BNL L. Gifford R. Youngblood, Consultant BNL G. Sherwood Open Session
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q MIN. GESSAR II MT.
2 SEPTEMBER 11, 1985 d
Mr. Dino Scaletti NRR GESSAR II Project Manager, preser.ted an update on the review of GESSAR II and commented on the day's agenda. He noted that in a. September 6, 1985 letter to R. Fraley, Executive Director.
ACRS from H. Denton, Director NRR, written responses were presented to a number of the agenda items. He noted the was not in a position to discuss safety goals at this time. Responses were provided to items that had direct implications or direct reference to safety goals that were directly applicable to GESSAR II.
Clarificat' ins to these responses would be made as necessary.
It was explained that Amendment I to the GESSAR II FDA was issued on August 9, 1985. This amendment allows the GESSAR II design to be referenced in new application. However, there is a condition in the FDA that prohibits the issuance of a CP or OL on an application that refer-ences the GESSAR II design until the completion of the severe accident review.
In summary, the design can be referenced, but it is not ap-proved.
Mr. Scaletti explained that the GESSAR II Standard Safety Analysis Report, its amendments and referenced documents, plus the Staff's Safety Evaluation Report along with its amendments, create the basis for issu-ance of a FDA. Mr. Rosenthal stated that referenced information in GESSAR II includes design details such as drawings in the structural and mechanical areas.
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Mr. Rubin, NRC Staff, noted that estimated core melt values presented in the staff's SER supplements are essentially mean values.
In their
MIN. GESSAR II MT.
3 SEPTEMBER 11, 1985
,e' evaluation of the GESSAR II PRA, Staff consultants BNL calculated mean core. melt frequencies for the dominant sequences of the internal events.
BNL also prepared a limited statistical uncertainty analysis. Core melt estimates for the seismic events were described as mean values, but in a somewhat more limited sense.
Structure and component fragilities were combined to form the mean system fragility curve. However, without a definite site there was a lack of detail in the site' hazard function.
It is believed large uncertainties exist in this area. Lacking an actual site, it was not possible to develop a meaningful hazard function and associated uncertainty distribution.
For calculational purposes, the GESSAR II site hazard function was assumed to represent a mean value. Aware of the limitations of this approach the Staff /8NL provided sensitivity analyses to attempt to bound the likely seismic core melt contribution, presented in SSER #4. An interface item has been specified to perform a site specific function analysis, and justify that the mean and mean plus one standard deviation of the site specific hazard are bounded by the GESSAR II seismic hazard function.
The Staff did not consider or include onsite costs in their cost / benefit considerations.
It was felt these considerations would not affect results by more than a factor of 2.
Staff recomendations were based on screening potential design improvements to within a factor of 10 to 100 based on cost / benefit and final selection of design improvements based on engineering judgment.
Mr. Scaletti stated that there is not a threshold for core melt frequen-cy for future plants. The Staff has endeavored to review GESSAR very
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SEPTEMBER 11, 1985 thoroughly with the understanding that future plants, based on the Connission's policy, should be safer. The results of the staff's review to date ha,s given the Staff the belief that GESSAR II is a safe plant, safer than ' existing plants.
Dr. Okrent asked if there was merit in allowing no single scenario to contribute more than one tenth of the design objective? The Staff replied they had not used such a philosophy on GESSAR. The Staff Las no current position on this reasoning.
Mr. Rosenthal explained the Staff does not have a containment perfor-mance guideline. The Staff has deterministically re-reviewed the GESSAR II containment. GE and the Staff and its consultants have examined containment threats due to steam and non-condensible gas production, hydrogen deflagarations, diffusion flames, hydrogen detonations and the potential for containment bypass such as seal failure and leakage.
After assessing the risk due to these potential containment failure modes, it has been concluded that the risk to the public is small. The most probable failure mode is predicted to be slow overpressurization due to non-condensible gas production.
For this failure mode, sup-pression pool scrubbing of radionuclides effectively reduces the conse-quences to the public.
It was noted that hydrogen igniters force containment failure scenarios to a later overpressure failure mode.
Postponing containment failure is worth an order of magnitude savings in person-rem predicted from the event. The reason given for battery backup on the igniters, is not that i
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5 SEPTEMBER 11, 1985 the risk is unacceptable without them, but rather to force an accident
.s scenario abnre a known, more benign course.
Dr. Okreht noted that there was not a sophisticated analysis of the effect of core melt on the structural behavior of the drywell. However, there is attached to a core melt event some unspecifiable likelihood that both drywell and wetwell integrity can be lost.
It was noted a philosophical question remains as to whether or not a containment design should be required that has a reasonably high degree of confidence that it will maintain its integrity through all scenario with the exception of venting through deliberate filtering systems.
Mr. Rosenthal explained that the Staff is requiring that the hydrogen igniter system *iave de battery powered backup because station black-out dominates risk.
This requirement is based on prudence not cost / benefit analysis. He explained containment sprays are not placed on battery power since passive heat sinks will maintain containment pressure with margin before failure.
In addition containment temperature rises to c
600 F. are acceptable from a materials standpoint.
In a severe accident situation without sprays, vital equipment could be lost. However, the j
core is already in a state (severe accident) the vital equipment was to prevent; and preserving the equipment becomes moot.
Mr. Scaletti explained that the Staff's list of interface requirements which it believes necessary to assure the PRA performance requirements, are achieved, are identified in Section 1.10 of the SER and its supple-ments.
The severe accident interfaces are listed in SSER-2,3, and 4.
MIN. GESSAR II MT.
6 SEPTEMBER 11, 1985 Quantitative requirements 'for these interfaces, if required, are iden-tified in an appropriate SER section identified in Table 1.10. Specific areas of 1,nterface requirements were presented and discussed.
s The NRC Staff presented a discussion on. number of generic items that were resolved for GESSAR II in SSER #4. USI A-43: Containment Emergen-cy Sump Reliability: was resolved on GESSAR II because the ultimate plant protection system provides an independent source of core cooling, regardless of whether or not debris blocks the RHR strainers in the containment sump.
USI A-47: Safety Implications of control systems to a large extent is outside the scope of GESSAR. Overfill transient protection from a hardware point of view appears adequate on GESSAR.
GSI B-6: Loads, load combinations, and stress limits were the concern in the ccupling of LOCA and SSE events for mechanical systems. Removal of pipa restraints will improve access to equipment areas and result in reduced occupational exposures. Currently GE has a leek before break application under review by the Staff. Removal of pipe restraints resolves this issue.
GSI B-58:
Passive Mechanical Failures gets a medium priority rating due to the high cost savings to the industry. At issue is the passive failure of mechanical valves between surveillance testing. GE has in-diented this is not a substantial problem, and the Staff has accepted t
MIN. GESSAR II MT.
7 SEPTEMBER 11, 1985 this issue as having limited safety significance.
It is resolved for GESSAR II.
GSI 82:
'Beyond Design Basis Accident in Spent Fuel Pool concerns large inventories of fission products in the pool. With the higher concen-trations of spent fuel and increased heat load, there is a threat of fire propagation between assemblies in an air environment. This item was resolved on GESSAR due to the fact the pool is a below grade seismic Category 1 structure. This reduces the likelihood of pool drainage and makes manual filling pf water easier to accomplish.
GSI 105:
Interfacing System LOCA at BWRs concerns over-pressurization occurring between high pressure systems and low pressure emergency core cooling systems.
If not mitigated this could lead to a LOCA outside primary containment. This issue does not directly relate to GESSAR, but rather to BWRs licensed before 1980. However Staff review assured that adequate precautions to prevent and mitigate such an event had been taken.
Itwasnotedthatprioritizegenericissues(USI'sandmediumandhigh GSIs) would be considered specifically on a standard plant untti the FDA is issued. After the FDA is issued, the backfit procedur? would be used to make design changes.
Mr. Knecht of GE discussed containment venting criteria and objectives.
He noted that containment venting procedures are outlined in the Emer-gency Procedure Guidelines. Venting would only be attempted after
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MIN. GESSAR II MT.
8 SEPTEMBER 11, 1985 normal methods of pressure control, e.g. standby gas system, or contain-ment sprays had been attempted. Specific venting procedures will be defined by, an utility applicant that raferences the GESSAR II design.
Venting could take place either from the control room (using the normal ventilation exhaust line) or from the UPPS station.
Mr. Knecht also discussed isolation valves on system piping that leads from the containment to the outside environment. The concern was had the valves been tested to ensure they are capable of closing under blowdown conditions. The trolation valves are within the GESSAR II scope of supp,1y.
Purchase requirements specify the valves work in a LOCA environment, be able to close against normal operating flows, and be able to close against break flows.
Mr. Pfefferlin, GE, discussed the control rod drive scram discharge volume.
It was noted there are two scram discharge volumes, each with its own instrua nt volume. The two volumes are cross connected. The cross connect allows either set of sensors to detect system conditions.
It was noted that the control rod scram system on the A8WR eliminates the discharge as associated volumes. However, you lose the ability to i
scram using reactor system pressure, so a trade-off is involved, i
The Subcomittee took up the topic of the UPPS. GE believed both the i
UPPS and fire protection system could operate coincidentally. GE was unsure about the effect sharing fire protection and UPPS functions would have, for example, after an earthquake. Concern was expressed over the present level of design of the UPPS at the FDA stage. GE stated they
h!N. GESSAR II MT.
9 SEPTEMBER 11, 1985 would be the designer and that a detailed design would take place with
+he first GESSAR II utility-applicant.
System i'nteractions were discussed.
It was noted this issue would become as interface requirement for a utility applicant. Concern was raised over how seismic interactions (nonseismically designed systems failing and interacting with seismically designed systems) would be specified in the interface requirements. The Staff noted spatially coupled interactions are investigated following plant construction.
l Regarding external floods, GE explained that applicants are not required to calculate the frequency of the probable maximum flood. The Staff's position is that for any plant whose safety related systems, components, and structures are located above the level of the design basis flood (DBF) the risk from external flooding is acceptably low.
Presently, the Staff believes any assignment of a probability to the D8F will be arbitrary and of limited value.
General Electric explained that the fire protection system is not seismically qualified. As a consequence of this fact no seismic fragil-ities were produced. The staff noted that portions of the fire pro-tection system within the GESSAR II scope are reviewed deteministically and the results reported in the Staff SER.
The NRC Staff noted that relay chatter is still an open item at this
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MIN. GESSAR II MT.
10 SEPTEMBER 11, 1985
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Mr. Knecht. GE, discussed the water hammer potential for the core spray system. Analyses show that the maximum pressure during a water hammer in this system is on the order of 20 psi. This pressure differential does not'cr'eate a problem.
(Closed Session)
The Committee went into a closed session to discuss safeguards details of a bunkered decay heat removal system used at a foreign plant.
4 Open Session The Staff and GE agreed to review the materials used in the chilled water piping. The concern was a brittle fracture of this piping at operating temperatures. The Subcommittee discussed the capability for inservice inspection of the lower reactor pressure vessel (RPV) head.
It was noted there are nine welds in the reactor pressure vessel lower head. Most are accessible for ultrasonic testing however some are not.
4 Control Rod drives and their housings have been exempted from inservice inspection because any leakage produced would be small. Rod catchers would limit the leakage areas around the control rods to a level that could be replaced by the plant ECCS.
I GE was questioned over how assurance could be sought that cracks would not form in the bottom of the RPV head, between different penetrations, ove; the forty year life of the plan'..
Some regions are not normally subjected to inservice inspection over the plants life. GE believes j,
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j that many cases are accepichle since failures in these regions can be controlled and do not lead to unaccsptable consequences.
It was.
however, explained that some failures, such as a vessel rupture between penetrations would lead to core melt. A group of four rods ejected from the core could lead to a novel accident scenario. A more global dis-cussion of quality assurance and fabrication techniques might be appro-priate.
Mr. Ebersole went through a number of his concerns on the GESSAR II Concerns included the present plant scram system and it's inter case.
connected scram dump volume. He also had concerns over various inter-face items. He also expressed some concern over perceived inaccuracies in the FSAR.
Dr. Okrent and the Subcomittee gave the Staff and applicant in-structions regarding presentations to the full Comittee.
The meeting was adjourned at 5:47 p.m.
(Meeting handouts are appended to the transcript.)
NOTE:
A complete transcript of the meeting is on file at the NRC Public Document Room at 1717 H Street, NW., Washington, D. C.
or can be obtained at cost from Ann Riley & Associates, Court Reporters 1625 I St., NW., Suite 921. Washington, D. C. 20006 (202)293-3950.
34023 Federal Register / Vcl. 50. Nm.163 / Thursday. August 22. taas / Notfoes ' ATTACHMENT AM
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Date and time: September s and a tene;.
%e Subcommittee will ommehnee les. Nucl:ar Reactor Regulation t> lsene to s
ano e a ta soo p a e:ch day.
revi:w of CESSAR U for a Baal deelga Philadelphia &ctric Company
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M place:The Nanonal Sdence Foundatlan. "
Room 12a21L 1seo C Street. NW. W *-
op royal applicable to future plants. '
)a full operating heanse G
statements may be presented by' Unit 1 of the ck Generating W Open. S/S-eco a.m. k members of the pub!!c with the Statica. Accordingly, the Director leeued Q,enographic Carrtere and Fac1Dum Secuan-Committe p a Closed he=F=Ae of useduled concurnnoe of sne Subcommittee,
Facihty Opereting Ucease No.NFF-as
' Chairman; written statements wtB be which, among other setboetoed g
ntact parece. MI Sandre' D. Toye. Head ' "* accepted and made available to time 6e Ucensee to operate faglity at (OCFS). Diviefour of Oceen Sciences. Roose ructor core power levels not la emesse j
813. Nanomal Sdence Foundance.
- only during those portfoes of the of 3.233 megewette thermal (1804 reled "4
,,a,shigton. DC aosan TW am/asr*
meeting when a transcrtpt Isletag kept, power). Usense No. NPF-as --
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and guestions may be asked only by dantet May be ebulmd from members of the Subcommittee,its '
Facility Opereting Ucense No'. NPF-ay.
,9, wh'ch wee issued on October as.19td.
the contact persoa listed above.
' consultants. and Staff. perseas desiring and which authortsed the Ucensee to Tm Purpose of advisory group: To provide to make oral statements should notify operate the facility at levels not to edvice to the Head. OGS. on the dispostuos the ACRS etaff member named below as amoeed 5% of reted power.
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elproposefs and receaunendauon affecting far in advance as le practicable so that
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appropriate arrsagements can be mode-unerick Ecology Acdos and %eensa
$E the composicon and dastnbution of the
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nda: Open Presentances ce the Durms the initial portion of the h4artin appealed the Commiselon's E
meeting, the Subcommittee, along with decialon and sought a stay of the Commission's Order bem the United oeeL5mYwan
""I *III* '*"*"II"Dta who may be oc o proposa!s u part of age w!,cuan proceu for Pmunt, may exchange pnuminarY States Court of Appeals for the %ird i
ev q
ewards.
views regarding matters to be Circuit. On August 15.1985, the court i, s
Rueon for desing N propoests belns considered during the hatanan of the further order of the court.%e effect of i
stayed b Commimlan's Order pending T'
i nviewed include wormanon of a propnetary meeting.
y er cormdeneal neeun, toc 1 techrucal ne Subcomm.ittee will then hear b court's order la to suspend operation s
g informamon, n===aat data.
as utaries; - presentations by and bold discussions above 5% of toted power. pending
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4 and personal 6aformenos concermas with representatives of the General further order of the court. The Uconsee g
intviduals associated with the propoesia.
Electric Company. NRCStaff, their has informed the NRC Staff that it le
'E k,75y'NMfce,"e's r'entItke consultants, and other latensted proceeding to reduce the power level of d
persons mgarding this myiew.
h facility to 5% or less of rated power.
genshine Act.
F Authority to claw antina This Further informstion regarding topics De purpose of this Order is solely to s
deternunanon wu made by the Committee to be discuued. whether the meetins effectuate the court's order and confires
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Management Omcer pursuant to provtsions has been cancelled or reacheduled. the
- the Ucensee's actions.nla Order will i
b et section to(d) of Putt L 82-481 N Chairman's ruling on requesta for the lift its stay.
be rucinded upon action of the court to L
Committu Management Omcer was opportunity to resent oral statements ESbeMy Accding! puvaant k secdone 105, ti nab h
., order of A o aIn d y a p dt a
to the cognizant ACRS etaff membee. Mr.
z mL August 13. tems.
App',1, i 15.1985, it le E
Richard Major (telephone 202/634-1413)
M.Esbeme Winkis.
between 815 a.m. and 5.00 p.m. Persons bm y dmd bt e Ucensee aball E
cameitme Manusement Of3cer.
planning to attend this meeting are reduce the opereting power level of the I
PR Doc. es.aoar7 rped 6.zs.en, mas am]
urged to contact the above named, -
facihty to 5% or lew of rated power by j
Individual one or two days before the ec00 p.m August to.1ss5, and shall not '
au me onesrees.ee.e u
em.
_ ocheduled mnting to be advind of any thmafter operate umerick Unit 1 above.
Lt.AM REQULATORY changes in schedule, etc., which may 5% of reted power until such restriction e
COMMIS$40N.
han occurnd.
is rescinded by the Dttector of the Of5ce m
s of Nucleat Reector Regulation.
2 Advhory Committu on Reactor Dete<L August is.1ses*
Dis Order la effective spec leemaaon, j
Sefeguards; Subcommittse on General M" "' h Electric Standard Safety Anafysis AseistantDectiere DhkW Deted at tetheeda. Maryland this Neb dey Moport (GESSAM 11) Mwting of Auguet sees.
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For N Neclear Regulatory f'==6=='=
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on Sept.m6-11.1965. Room 1187.171y. (Deesouse. 86 363)
PR Doc, es-am44 Filed 6-as-ess tes am) g H Street. NW, Washington. DC.
To the extast practical, the meeting.
Phnod@ Electric Ca. M 8'8"*******"'
will be open to pubbe attendance.
Generating Statlori. Unit 1) Order However, portiohs of the meeting may Suspending Operation Above 5
.- Percent Power PACIFIC NORTHWEST ELECTRIC be closed to discuse proprietary information relating to the CESSAR In its Memorsndam and Order of POWER AND CONSERVATION probabilistic risk enessment and plant' August a. tess. the Coeunfulon declined Pt.ANNING COUNCIL.
escurity.,de 'or the sab[ect meeting to stay the effectivenese of the Atomic Estebashment e8 Mainetem Pesesse De agen f eball be as follows.
safety and Ucensing Board's Fourth
. Adyteory Committee Partial Injtjal Decision in the Umerick Wedneadey $eptember11.1sas.-4.30 opereting Ucense promeding and ammec r: Pecific Northweet Electria am until the conclesion of busineu; authorized b Dinctor of the OfBoe of Poww and Conservation Plaanleg d
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TENTATIVE SCHEDULE FOR THE ACRS SUBCOMMITTEE ON GESSAR II SEPTEMBER 11, 1985 WASHINGTON, D.C.
8:30 AM 1.
Chairman's Opening Remarks (10 min)
- a. Objectives
- b. Goals
- c. Schedule 8:40 AM 2.
Update by NRC Staff, current status of (15 min) the GESSAR II FDA.
Future Activities planned 8:55 AM 3.
Staff Discussion - Using mean estimates of (30 min) risk and following the recomendations of the Safety Goal Evaluation Steering Group, chaired by T. Murley, for the consideration of onsite costs:
How would these assumptions affect cost / benefit results?
(written reply prior to meeting requested) 9:25 AM 4
StaffDiscussion-H.Dentgnhasproposeda (15 min) core melt frequency of 10' reactor / year for present plants.
Is this also an objective for future plants?
(written reply prior to meeting requested) 9:40 AM 5.
Staff Discussion - Has the Staff considered (15 min) requiring a more stringent overall design objective for core melt frequencies for future reactors? The approach used in many countries is a not allow any single scenario l
to contribute more than 1/10 of the design objective.
Does the Staff feel there is merit in this approach?
(written reply prior to meeting requested) j 9:55 AM BREAK (10 min) 10:05 AM 6.
What is the Staff's best estimate on (20 min)
Containment Performance Behavior? In a discussion the Staff shot ed describe how they would characterize their review of containment performance. What is the drywell vulnerability to core melt sequences?
(written reply prior to meeting requested)
What is the Staff position on back-up,What (20 min) 10:25 AM 7.
power supplies for hydrogen ignitors?
is the rationale for requiring Containment
GESSAR II 9/11/85 2
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Sprays to be powered from emergency diesels,
..J but no requirement for back-up power supplies?
(written reply prior to meeting requested) 10:45 AM 8.
Staff estimate for mean core melt frequency.
(20 min) allowing for appropriate uncertainty dis-tribution. Details on basis for estimate.
(SeeJuly 17, 1985 ACRS Report on proposed NRC Safety Goal Evaluation Report for discussiononuseofmean,notmedianvalues.)
(written reply prior to meeting requested) 11:05 AM 9.
Staff Discussion, centered on a written list (20 min) of NRC Staff requirements which will assure that PRA performance requirements are achieved, to include
- equipment fragilities
- reliability criteria that must be met in in an effort to ensure assumptions made in the PRA are accurate.
In general what quantitative requirements are placed on GE and on an applicant? How are
- uncertainties included?
(written reply prior to meeting requested) 11:25 AM 10.
Discussion by General Electric - Containment (20 min)
Venting - When is it proposed? Discussion of criteria and objectives.
11:45 AM 11.
DiscussionwithGEandStaff(CLOSEDSESSION)
(15 min)
What has General Electric done to reduce the risk from sabotage for GESSAR II beyond current levels. Why is this appropriate for a future plant?
What cre the detail". Involved in pricing previously discussed bunkered system?
What are the costs associated with specific areas of the system? What would be the difference in price between a forward fit system and a backfit system?
12:00 Noon LUNCH (1hr) 1:00 PM
- 12. NRC Staff and GE Discussion of (1hr)
- MAJOR Review Results and conclusions from the PRA (from SSER 4)
Consequences and Risk from Internally Initiated Severe Accident Events Areas most critical to Internal Events Consequences Consequences and Risk from Externally InitiatedSevareAccidentEvents(seismic)
Areas Most Critical to the External Events Consequences
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GES'SAR II 9/11/85 3
What are the largest uncertainties and why?
2:00 PM
- 13. NRC Staff and GE Discussion of Unresolved (1hr)
Safety Issues and Generic Safety Issues l
(fromSSER4)
USI A-43: Containment Emergency Sump Reliability USI A-47: Safety Implications of Control Systems USI A-48: Hydrogen Control Measures GSI B-6: Loads Load Combinations, Stress Limits GSI B-58: Passive Mechanical Failures I
l GSI 82:
Beyond-Design-Basis Accident i
in Spent Fuel Pool GSI 105:
interfacing System LOCA at BWRs 1
l How are those identified generic issues that are yet to be prioritized handled in the GESSAR Il review? What would be the " cut-off" date when new generic items would no i
longer be considered?
3:00 PM BREAK (10 min)
GE and NRC Staff Discussion of the Following Topics:
3:10 PM
- 14. Systems interaction will become an (10 min) i interface requirement for a utility I
applicant. How will this interface j.
requirement be specified (in detail)?
j 3:20 PM
- 15. Discussion and documentation to show (10 min) i piping lines leading from the containment to the outside environment were equipped with isolation valves that have been speci-l fied and tested to ensure they are capable of closing under blowdown conditions. The effects of valve aging have been raised as a concern; how is this addressed? The i
reactor water cleanup system was mentioned I
as a specific example of this issue.
i 3:30 PM 16.
Issues related to Control Rod Drive Scram (10 min)
Discharge Volume
- Brief description of system
- Ability to vent and drain discharge 3
volume
- Ability to vent and drain individual drives j
- Comparison to ABWR scram system 3:40 PM
- 17. Has an evaluation of the pros and cons (10 min) associated with the UPPS hen conducted?
What are the results? Could this system initiate or exacerbate an off-normal :
situation? What performance requirements are l
specified, what allowance for uncertainties l
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GESSAR 11 9/11/85 4
are made?
3:40 PM 18.
Regarding the threat from an external flood, (10 min) does the interface information provided to an applicant who purchases GESSAR II instruct him to not only calculate the probable maximum flood (PMF) but also evaluate the frequency of the probable maximum flood? Will an applicant be encouraged to consider the chance of exceeding the PMF and decide if it is acceptable?
4:00 PM 19.
Discussion of the fire protection system.
(10 min)
What are the seismic fragilities of various components in the fire protection equipment?
4:10 PM 20.
Status of open items related to relay (10 min) chatter (Staff)
What are the quantitative requirements that must be met by plant equipment?
4:20 PM 21.
General Electric discussion of an assessment (10 min) of the water hamer potential of the core spray system. Additional discussion of water hamer potential for a pump start logic control and sequencing procedure for starting a pump with an open discharge.
4:30 PM 22.
Brief discussion on possible.dverse effects (5 min) associated with entrained air on RHR pump performance. The assumption is small well-mixed air bubbles in the suppresion pool being drawn into the pump suction.
4:35 PM 23.
Staff discussion of details of review (10 min) strategy and materials considerations for the following systems:
- non-safety-grade chilled water system
- non-safety-grade drywell chilled water
- safety-grade control building chilled water system How comprehensive is SRP Section 9.2.27 4:45 PM
- 24. What is the capability for Inservice (10 min)
Inspection of the lower reactor pressure vessel head? Why is this sufficient?
4:55 PM 25.
Closing Remarks l
The full Comittee session is currently scheduled for the l
following morning, September 12, 1985 from 10:30 AM to 3:30 PM.
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