ML19350E523
| ML19350E523 | |
| Person / Time | |
|---|---|
| Issue date: | 04/11/1981 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| Shared Package | |
| ML19350E524 | List: |
| References | |
| ACRS-1842, NUDOCS 8106230226 | |
| Download: ML19350E523 (4) | |
Text
-
DATE ISSUED:
4/11/81
!q f
SUMr!ARY/MINITIES OF TiiE N~
(
v l
g ACRS SUBCOMMITTEE MEETING ON fy - h, EMERGENCY CORE COOLING SYSTEMS s
MARCil 27, 1981 ff///h PASADENA, CA The ACRS Subcommittee on Emergency Core Cooling System: ' eld a meeting on Mscch 27, 1981 in Pasadena, California.
Mr. Paul Bochnert was the Designated rederal Employee for the meeting.
Selected slides and handouts used at the meeting are attached. A complete set of slides and handouts are attached to the office copy of these minutes.
Purpose:
The purpose of the meeting was to discoss the proposed test matrix for the LOFT f acility in light of the recommendations of the ACRS, the LOFT Specf sl Review Group (LSRC), and the Commission.
o N
19)
Attendees 9
Meeting attendees are listed below:
(
g ACRS NrtC u.s. met i
cu M. Plesset, Chairman 11. Sullivan /
{/7 D. Ward, !! ember R. Landry W. Mathis, Member 6)
A. Acosta, Consultants INEL I. Catton, Consutlant J. Lienhard, Consultant K. Condie T. Wu, Consultant Z. Zudans, Consultant Federal Republic of Germany P. Boehnert, Designated Federal Employee (DFE)
H. Karwat Meeting Highlights Agreements, and Requests 1.
Prior to beginning discussion of the meeting agenda items, Dr. Plesset noted that the ACRS recently (March 1981) approved operation of the San Onfore plant and that this CE plant will operate with a DNBR of 1.19.
Dr. Plesset felt that the ACRS should explore the implications of CE's use of a 1.19 DNBR.
It was noted that an ad hoc ACRS Sub-committee had been established to review the use by CE of a 1.19 DNBR.
Dr. Plesset felt that a combined meeting of the ECCS and Reactor Fuel Subcommittee would be a more appropriate and instructed the DFE to explore this suggestion.
THIS DOCUMENT CONTAINS P00R QUAUTY PAGES 8106 23 0 NM
+- -
. ECCS. Summary /Hinutes
. March 27,7 1981 p
2.-
Dr. H. Sullivan provided an overview of the recommendations of the LOFT Special* Review Group (LSRG). The LSRG considered NRC ret'latory needs in'the areas'of:. LWR safety analyais, degraded core cooling, reactor operational. aspects, and risk-reduction. The chief findings of the LSRG include: -(l) additienal LOCA tests. should be run to aid code assessment and quantify safety margins, (2) some anticipated transient tests should be run but the use of operating reactors to obtain such data is preferred, (3) severe transient tests could assist in confirming AIWS and inadequate core-cooling models, but early cantamination'of LOFT should be avoided. Other LSRG recommendations included: NRR must take a more active role in identifyicg LOFT-test needs, severe fuel damage studies are peripheral to i.he facility's use, and man-machine studies should not be, conducted at LOFT.
The LSRC recommend,a test matrix for LOFT.
Three sets of tests labelled high, medium, and low priority were developed (Figure 1).
3.
Dr. Sullivan described the NRC RES response to the LSRG-proposed LOFT test matrix (Figure 2).
The primary emphasis of the RES test matrix was on LOCA and transient code improvement and assessment. The RES proposed-matrix is consistent with the LSRG high priority tests with one exception - due to facility limitations. The matrix also contains four contingency tests (Figure 2).
The anticipated RES ;natrix would result in completion of testing in early 1983.
It was noted that INEL has not reviewed or committed to the proposed schedule.
RES proposed.five LOFT budget options to the Commission in early February. The Commission expressed support for Option 2 (Figure 3).
This option allows:
(1) testing to mid-83 (at the latest), (2) a two-year " safe storage" for the. facility to allow for additiona.1 testing if needed and (3)-decontamination and decommissioning of the facility in 1985 or 1986. Total cost was projected to be approximately
$128M.
- 4. ~ Dr. R. Landry (RES) ' described the most recent proposed LOFT test program (Figures 4&5). This matrix includes tests recommended by NRR.
9
, e=r -S*
4 3,;
...a ss.
139 ECCS Summary / Minutes' March'27, 1981
~ There was detailed. discussion of the above proposed ' test matrix.
At-1the conclusion of the discussion, the Subcommittee provided the follow-
.ing recommendations at the raquest of RES:
~
^
~ Test ? 5-1/L8-2 (intermediate-break LOCA) shculd be rescheduled to make use~of a new pressurized center fuel bundle that contains' internal-thermocouples.-
'Iest L2-5f(double - ended CL-break LOCA-cladding damage not expected) wa s supported-with reservation (concern expressed over.usefulness'of data optained).
Test LA-10 (boron dilution) was supported only as an add-on or piggyLack test.
' Tests L9-3 and LA-3 (ATWS tests) received no support but fur ther.
justification by RES was requested.
RES will respond at a future Subcommi.ttee meeting.
'Ter*s LA-9 (SB LOCA) and LA-2 (intermediate-break LOCA) were accepted by the Subcommittee.
' Test L2-6 (double ended CL break LOCA-cledding swelling and rupture expected) was supported, but the Subcommittee suggested that the test be run-before the end of FY 1982.
Dr. Sullivan said he would like to meet again with the Subcommittee to discuss justification for tests L9-3 and LA-3 as well as discuss
'the possibility of moving test LS-1 as suggested by the Subcommittee.
. The meeting.will be held in the near future at RES request.
5.
At'the Chairman's request, Dr. Helmut Karwat from the University of Munich provided some comments on research efforts in general and the LOFT program in particular. He said that he would support at least one more large break test in LOFT that would " challenge" the pr.edic-tive capability.of the codea.
Dr. Karwat also said he suggested that a gas sample system be installed on LOFT to aid study of steam-phase radiolysis for its effect on zirconium oxidation during small-break tests. In ger.eral, Dr.. Karwat expressed the opinion.that a facility on the. scale of. LOFT (a#1:60) aids code improvement more than a facility like Seimscale with.its smaller scale (a#1:1500).
e.,
..n,,
5 Y
v f[
c JECCS Summary / Minutes-. March 27,'1981.
1 M6, f
9
~
6, LMr. K. ' Condia -(EC&G) provided details of the results of the LOFT small-break pumps-on.(L3-6) and pumps-off (L3-5) tests.
These two tests showed that with' pumps-on there was higher break flow and lower system inventory. The core was completely uncovered ~in the. pumps-on test-yet. core cooling continued at high system void fractions.
Mr.
W
.Condie said.these two tests support the NRR requirement that operating
' plants trip their RCP's in the evant of a small-break LOCA.
The code Lpre-predictions for the two tests were no: accurate.
A number of changes
.have been made'to the codes.
[It is expected that these code changes vill be tested in-a future LOFT small-break test.'}
'7.
- u.. - Sullivan provided a brief overview of the RES ef fort on water hammer ~research..There is no experimental research underway at pre-sent.
Dr. Sullivan also said NRR does not believe water hammer effects represent a serious-or immediate safety threat.
RES is awaiting publi-cation of a NUREG that will specify NRR action on findings to date. The on1 possible: area for research that RES sees is study of steam bubble collapse. A listing of pertinent reports addressing water hammer study was also reviewed (Figures 6-6 7).
Future Meetings:
There will be another ECCS meeting to allow RES to report on the suggestions
. of the Subcommittee noted above.
E