ML20235N177
| ML20235N177 | |
| Person / Time | |
|---|---|
| Issue date: | 06/05/1987 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2503, NUDOCS 8707170461 | |
| Download: ML20235N177 (14) | |
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g DATE ISSUED: June 5, 1987
SUMMARY
/ MINUTES ACRS NUCLEAR PLANT CHEMISTRY SUBCOMMITTEE WASHINGTON, D.C.
MAY 19, 1987 The Nuclear Plant Chemistry Subcommittee met at 1:00 p.m., May 19, 1987,
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Room 1046, 1717 H St. NW, Washington, D.C.
The purpose of the meeting was to be briefed and to discuss the proposed revisions to Standard-Review' Plan Sections 6.5.2 Revision 2 " Containment Spray as a Fission Product Cleanup System", and 6.5.5 Revision 0 " Suppression Pools as Fission Product Cleanup System."
Notice of this meeting was published in the Federal Register on May 13, 1987 (Appendix A). The schedule for this meeting is in Appendix B.
A-list of attendees is in Appendix C.
A list of the handouts is in Appendix D.
The handouts are filed with the office copy.
Principal Attendees ACRS Members Consultants D. Moeller, Chairman M. First J. Ebersole D. Orth (P/T)
C. Mark (P/T)
NRC j
L. J. Hulman, Office of Research i
L. Soffer, Office of Research l-J. Read, Office of Research Introductory Remarks:
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Minutes / Nuclear Plant Chemistry 2
e Mt., May 19, 1987 i
Chairman Moeller called the meeting to order at 1:00 p.m.
He introduced the ACRS Members and Consultants present. He asked if there were any consnents.
i Mr. Ebersole pointed out that at times it may be desirable to release a very. small amount of radioactive material by venting through the suppression pool to prevent a potential catastrophic later core melt.
Mr. Ebersole noted that this use of the suppression pool is not mentioned in the proposed SRP.
Mr. Hulman responded that Mr. Ebersole's point was a very good one, and more work on the use of suppression pools as a preventive device for core melt needs to be done. He noted that the two standard review plans were not the place to discuss Mr. Ebersole's point.
Mr. Hulman stated the purpose of the discussions was to obtain any ACRS comments on the revised versions of the SRP's that were issued for public comment.
Chairman Moeller invited Mr. L. J. Hulman to begin the presentation.
Severe Accident Issues Branch, Office of Research S.R.P. 6.5.2 - L. J.
Hulman, Branch Chief Mr. Hulman pointed out that Mr. Soffer would discuss the rationale for the changes to the two standard review plans, Mr. Reed would discuss the
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. Minutes / Nuclear Plant Chemistry 3'
Mt., May 19,.1987 C
.techn'ical bases-for the. changes and that he (Mr. Hulman)'would discuss the regulatory implications.
Mr. Hulman discussed 10 CFR Part 100 and its reference to TID 14844.
These documents referred to accidents beyond the design basis accident l
and to consideration with respect to siting and with respect to engi-neered safety features.
Changes resulting from source term research have necessitated changes in the two SRP's that are under discussion.
I Severe Accident Issues Branch, Office of Research - Lynn Soffer, Section Leader Mr. Soffer discussed the present version of SRP 6.5.2.
He noted a spray additive is strongly encouraged.
It is not required but'it is strongly encouraged.
If it is present, it is required to be injected automat-ically. He remarked that a delay of up to 90 seconds is allowed for the
- injection.
He stated the present standard review plan gives low iodine removal credit unless the pH in the sump is greater than 8.5 and there are no explicit models for spray removal coefficients or plateout deposition.
In response to a question by Dr. Moeller, Mr. Read stated that recircu-lation takes place usually within 20 and 45 minutes.
l Mr. Hulman remarked that there were three major points that are proposed to be changed. One is that the revision removes the emphasis on the
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l Minutes / Nuclear Plant Chemistry 4
Mt., May-19, 1987 i
immediate injection of spray additives.
It retains the post accident sump pH control but at a lower pH level. The new pH requirement is'7.0.
The evaluation of the spray now includes-other fission products in addition to iodine.
The reference to TID 14844 has been deleted. The intention is to use TID 14844 or the intended revisions to Regulatory Guide 1.3-1.4 which have yet to be written.
i There is no licensee action that is required; the action is voluntary.
The revised SRP sections will allow BWR spray systems to be reviewed for fission product removal.
Presently, the BWR spray systems are reviewed for pressure reduction but not for fission product removal.
Severe Accident Issues Branch, Office of Research - Jacques Read, Senior Reactor Systems Engineer 4
Mr. Read discussed the technical basis for the proposed changes. He l
noted, in particular, Japanese and Italian papers. The Italians tested a one percent solution of sodium thiosulphate as a spray and compared it to the local tap water for fission product removal. There wasn't any I
l significant difference.
Mr. Read pointed out that there wasn't any evidence that between a pH range of 7 to 9, any one pH was more effective. Mr. Read noted problems with certain additives. Sodium thiosulphate has to be stored in a 1
Minutes / Nuclear Plant. Chemistry 5
l.T Mt., May.19,1987 l
g sterile state.
It decomposes to form sulphur compounds that'can be very 1
detrimental to nickel alloys. Hydrogen combines very readily with oxygen.
It is possible for hydrazine used in a spray to be oxidized before'it reaches the containment sump.
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l Mr.. 'Hulman - Regulatory Implications Mr. Hulman noted'that the proposed implementation for SRP 6.5.2 was voluntary. The licensees can maintain the status quo if they so desire.
They can have automatic addition of spray additive, manual addition or-no additives at all. They must assure pH control. One benefit of the revision is that it is independent of the source tenn assumptions. Mr.
Hulman pointed out that the revisions would not result in any changes to public risk.
. Dr. Moeller asked what the French and Germans use for additives. Mr.
Soffer responded that he thought the French use additives and the Germans do not.
He remarked that he thought the French use sodium hydroxide.
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Mr. Hulman observed that the revised SRP has the potential for reducing personnel hazards in maintenance and operations.
He noted that NRC staff requirements to review license amendments to make these changes would be small.
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Minutes / Nuclear Plant Chemistry 6
Mt.,.May'19, 1987 In response to a question by Dr. Moeller, Mr. Read responded that the pH of the suppression pool would be about 7.
Mr. Ebersole asked how the carbon steel vessels are prevented from rusting. Mr. Read answered that they are generally painted.
Dr. Moeller remarked that, with the new approach, credit will be given for the spray as an iodine removal mechanism. Mr. Hulman concurred.
SRP 6.5.5 - Mr. L. Soffer - Status and Overview 1
Mr. Soffer noted that, at the present time, no credit is'given in Regulatory Guide 1.3 for suppression pools as a fission product cleanup system.
However, SRP 6.5.3 stated that pool credit may be given, but it provides no procedures or criteria for the staff to do so.
He noted that during the GESSAR 2 review, the staff allowed credit for fission product scrubbing in the suppression pool as part of the severe accident risk evaluation.
Dr. Mark asked if there were procedures for the amount of credit that could be claimed? Mr. Soffer said no.
i Mr. Reed pointed out that the problem with GESSAR was that the bypass from the drywell into the containment around the suppression pool was in the balance-of-plant scope. GESSAR didn't cover this, so the staff didn't deal with the credit for suppression pool scrubbing at that time.
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Ainutes/NuclearPlantChemistry.
'7 Mt., May 19.-1987 Mr. Soffer noted the chances that the revised SRP would provide.
It would permit credit for suppression pools as fission product cleanup i
systems. Conservative decontamination factors would be' incorporated'in
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l the SRP They would be allowed with no applicant analysis. Any I
suppression pool bypass leakage must be accounted for in' dose calcu-1 lations.
Existing ESF charcoal adsorption systems are not to be degraded below the minimum value, i.e., 90 percent efficiency. The revisions are not dependent on any particular source term.
Jacques Read, Technical Bases Mr. Read said the.R&D is evaluated on the basis of the SPARC code which is part of the source term code package.
Dr. Moeller asked to what degree had the SPARC code been evaluated? He remarked that the Brookhaven Laboratory report seemed rather inconclusive in terms of discussing the SPARC code.
j Mr. Read remarked that the SPARC code was the best that they had.
Mr. Hulman pointed out that it was important to recognize that Brookhaven apparently was concerned about the wide variation of experi-mental data and the inability of any code to model the actual situation.
Mr. Read noted that a major simplification used in the SRP has been to i
use time averaged effective decontamination factors.
Minutes / Nuclear Plant Chemistry 8-Mt., May 19, 1987-Mr. Hulman remarked that there wouldn't be any real benefit to any licensee'or applicant to assume a large decontamination factor. This is due to the fact that the dose is dominated by the suppression pool bypass.
It is posrible for a large fraction of the flow to go around the suppression pool.
Dr. Moeller asked if there was a regulatory limit on bypass? Mr. Read responded not really. He noted SRP 6.2.3.1 that has some limits. Mr.
Hulman'added that type C containment tests are limited in total leakage to the total minus the bypass.
Mr. Read pointed out that the amount of time that a discharge bubble
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J would spread under water is an important consideration. He noted that i
this time is least for Mark I containments.
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i Regulatory Impacts of Changes - L. Hulman Mr. Hulman remarked there would now be a little more realism in the design basis LOCA dose calculations.
He also noted that there are potential relaxations that could be applied to the performance requirements for BWR mitigated ESF's. These relaxations could come I
through changes in the Tech. Spec. or in the testing requirements.
I There is a possibility that containment leak rates may be relaxed. This is the subject of future work.
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Mi.nutes/ Nuclear Plant Ch:mistry 9
-Mt., May 19, 1987 Mr. Hulman observed that the stand-by gas treatment systems and other safety-related filters have testing requirements that are, in some
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measure, dependent on dose estimates and fission product release as-sumptions.
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Mr. Hulman pointed out that utilities may.take advantage of. suppression pool scrubbing to reduce the test requirements on MSIV testing. He added that along with the proposed relaxation the staff will be evaluating the bypass more closely.
4 Dr. First pointed'out that he was bothered by the concept of relaxing charcoal adsorption requirements by taking credit for suppression pool scrubbing.
He remarked that the best available technology in filtration should be used.
Mr. Hulman responded that it's relatively easy to propose best available technology, but from a regulatory perspective, he wasn't sure it was warranted.
The meeting was adjourned at 3:35 p.m.
In a subsequent Executive Session, the Subcommittee prepared a written sumary of its comments on the revisions in the two Standard Review Plans.
NOTE:
A transcript of the meeting is available in the NRC Public Document Room, 1717 H Street, NW., Washington, D.C. or can be l
purchased from ACE-Federal Reporters, 444 N. Capitol Street, Washington, D.C. 20001(202)347-3700.
,g m p yy 18036 Feder"! Register / Vol.'52. Ns. g2 / Wednisd y. M y 13, 1987 / Notices q
Advloory Committee on Reactor Dated: May a.1ser.
Deted: May 7.1987 Sejeguvde Subcommittee on Nuclear Morten w. Uberkin.
Marten W.Uberkin 4
Plsntt Chemistry; Heeting Assistant Executive Directorfor Project Assistant txecutive Director of Project l
Reelew.
Review.
%e ACRS Subcommittee on Nuclear
[m Doc.87-10sso riled 5-12-87; 8:45 amj
[m Doc. 87-10sB1 Filed 5-12-a7; 8.45 am]
Pl:nt Chemistry will hold a meeting on
=== sees neww same come sawus
- May 19.1987. Room 1046,1717 H Street.
NW., Washington, DC.
Advisory Committee on Reactor SECURITIES AND EXCHANGE
%e entire meeting will be open to Sofeguards Subcommittee on MISSN public attendance.
Regulatory Po5cies and Practices,
%e agenda for subject meeting shall Meeting (Reisese No. M-24430; Fne leo. SR-CSOE-be es follow's:
The ACRS Subcommittee on i
Regulatory Policies and Practices will Self Regulatory Organizations; Tuesday. May M, as7-140 P.M. until hold a meeting on May 28.1987, Room Proposed Rule Change by the Ch6cego i'
the conclusion of busmess tooe,1717 H Street, NW., Washington.
Board Options Eachenge. Inc. Relating The Subcommittee will review SRP DC.
to Liability for Payment of Debts section B.51" Containment Spray as a
%e entire meeting will be open to Fission Product Cleanup System." and pu lic attendance.
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SRP section 6.5.5. " Suppression Pools as The agenda for the subject meeting Securities Exchange Act of 1934.15 Fission Product Cleanup Systems."
shall be as follows:
U.S.C. 78s(b)(1), notice is hereby given that on March 16.1987, the Chicago Oral statements may be presented by Tuesday. May 28. ser-d:x a.m. until Board Options Exchange. Incorporated members of the public with concurrence the conclusion ofbusiness filed with the Securities and Exchange of the Subcommittee Chairman: written The Subcommi; tee will continue its Commission the proposed rule change stetements will be accepted and made current review of the nuclear plant as described in items L H and IU below, available to the Committee. Recordings regulatory pmcess.
which items have been prepared by the itted only during those Oral statements may be presented by
] bl a the meeting when a members of the pubhc with the i notice to transcript is being kept, and quessons concurrence of the Subcommittee solicit comments on the proposed rule assy be askedonly by members of the Chr.irman; written statements will be change from interested persons.
Subcommittee, its consultants. and Staff, accepted and made available to the L Text of the Proposed Rule Change Persons desiring to make seal Committee. Recordings will be permitted Additions are italicized; there are no sttements should notify.the ACRS staff only during those portions of the deletions.
members as far in advance as meeting when a transcript is being kept, practicable so that appropriate and questions may be asked only by LiabilityforPayment arrangements can be made, members of the Subcommittee,its Rule 2.23. A member that does not pay Durint g gg Pw&m consultants. and Staff. Persons desiring any dues, fees. assessments. charges, meeting, the Subcomnuttee, along with to make oral staterments should notify fines or other amounts due to the the ACRS staff member named below as Exchange within 30 days after the same cny ofits consultants who may be far in advance as is practicable so that has become payable shad be reported to present. may exchange preliminary appropriate arrangements can be made.
the Chairman of the Executive views regarding matters to be During the initial portion of the Committee who may, after giving cons.idered during the balance of the meeting. the Subcommittee will reasonable notice to the member of such meetin8 exchange preliminary views regarding arrearages, suspend the member until ne Subcommittee will then hear matters to be considered during the payment is made. Should payment not presentations by and bold discussions balance of the meeting.
be made within 6 months after payment
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with representatives of the NRC Staff, he Subcommittee will then hold is due a regular membership may be
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b oonsultsnts. and other interested discusalons with past and present disposed of by the Exchange or a special q
persons reganiing this review, representatives of the NRC regarding membership may be disposed of or l
this review.
cancelled by the Exchange,in Fweer hfwmuon repeding bpics Further information regarding topics accordance with Rule 3.14(b). A penon
' ta be discussed'lkd w macheduled. &e to be discussed. whether the meeting association with a member who fails to whether the meeti 8 y g,,,.
Chainnen.s mung on meests fw ee has been cancelled or rescheduled. the pay anyfme or other amounts due to the opportunity to passent oral statemerits Chairman's ruling on. requests for the Exchange within M days after such
&e Mme eBehed eerda can be opportunity to present oral statements amount has becomepayable and after and the time allotted therefor can be reasonable notice ofsuch armamges, chained by a ympaid klephone cau e obtained by a prepaid telephone call to maybe suspendedby the Chairman of the cogelsant AC3tS staff member Mr.
the Izant ACRS staff member.Mr.
the Executive Committee from W C a. Dele h Gary ittschreiber (telephone 202/634-associated with a member until s WElbstween 8 a.us,p one 202/eH..
apd 5:00 p.m...
3287) between 815 a.m. and 5-00 p.m.
payment is made.
b P arming to attahd this meeting l
mO0ptb cosnact he A6ove' named Persons planning to attent this meeting
... Interpretations andPolicies are uryd to contact the above named
.01 Reasonable notice under Rule E. heuttial'ese er hire daydefore the ' - individual one or two days before the 2.23 shallinclude, but is not limited to.
'as4td f d meeting to be ~ advised of any scheduled meeting to be advised of any service on a member or associated ue c6 andes in schedule, est.lwhich may
. changes is schedule, etc., which may penon's address as it appears on the i
kaso occursed.
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books andmcords of the Exchange hN y
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. TENTATIVE SCHEDULE NUCLEAR PLANT CHEMISTRY SUBCOMMITTEE MAY.19. 1987, ROOM 1046 1717 H STREET NW, WASHINGTON, D.C.
1:00 to 5:00 p.m.
SRP 6.5.2 "CONTAINMEt'T SPRAY AS A FISSION PRODilCT CLEANUP SYSTEM" 1:00 p.m.
Introductory Renarks - D. W. Moeller, Chairman 1:15 p.m.
Rationale for_ Revision - Jerry Hulman 1:45 p.m.
Technical Basis-f'or. Revision - Jerry Hulman 2:15 p.m.-
Reculatory Implication - Jerry Hulman 2:30 p.m.
Subcommittee Discussion 2:45 - 3:00 p.m.
BREAK
-SRP 6.5.5
" Suppression Pools as Fission Product Cleanup Systems 3:00 p.m.
.Pationale for Revision - Jerry Hulman 3:30 p.m.
Technical Basis for Revision - Jerry Hulman 4:00 p.m..
Regulatory Implication - Jerry Hulman 4:30 -
Subcommittee Discussion and ADJOURN 5:00 p.m.
' Room 1046,'1717 H St NW Washington, D.C.
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May 19. 1987 ATTENDANCE LIST
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DATE May 19,1987
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l APPENDIX D 1.
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HAND 0VTS 1.
Staff Handout, SRP Revisions A.
6.5.2 Containment Sprays as Fission Product Cleanup Systems B.
6.5.5 Suppression Pools as Fission Product Cleanup Systems I
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