ML19260C453
| ML19260C453 | |
| Person / Time | |
|---|---|
| Issue date: | 11/05/1979 |
| From: | Hofmayer C Office of Nuclear Reactor Regulation |
| To: | Vollmer R Office of Nuclear Reactor Regulation |
| References | |
| REF-GTECI-A-02, REF-GTECI-RV, TASK-A-02, TASK-A-2, TASK-OR NUDOCS 8001030484 | |
| Download: ML19260C453 (4) | |
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November 5, 1979 MEMORANDUM FOR:
R. H. Vollmer, Acting Assistant Director Systematic Evaluation Program, D0R THRU:
D. M. Crutchfield, Chief Systematic Evaluation Program Branch, 00R FROM:
C. H. Hofmayer, Section Leader Engineering Section pu4'-
Systematic Evaluation Program Branch, DDR
SUBJECT:
DELETION OF SEP TOPIC 111-8.0, " CORE SUPPORTS AND FUEL INTEGRITY" We recommend that SEP Topic III-8.D (Attachment 1) dealing with reactor core supports and fuel integrity for both pressurizid and boiling water reactors be deleted from the program or at least classified "outside generic" on the basis of the following discussions.
1.
Pressurized Water Reactors (PWRs)
For PWRs (including the SEP PWRs), the LOCA effects on core supports and fuel integrity is presently being considered on a generic basis in Technical Activity A-2, "Asyninetric Blowdown Loads on PWR Reactor Vessel". The Engineering Branch (EB) DDR is the 13ad branch in this effort.
2.
Boilina Water Reactors (BWRs)
Plans for resolution of the LOCA effects on core supports and fuel integrity for SWRs are being developed by EB, DOR. However, this issue is considered of a lesser safety significance than for PWRs.
The potential loads are not expected to be as large, since the reactor vessel pressure and subcooling are substantially lower than for PWRs (i.e. 1000 psia and approximately 40 Btu /lb, respectively for BhHs compared to 2200 psia and 100 Btu /lb for FWR plants).
The extension of Technical Activity A-2 to BWRs or an equivalent new program has been discussed for some time, but has not been implemented.
If such a program is not conducted it will require a significant effort in the SEP to resolve this topic. Furthermore, the level of effort required to resolve SEP Topic III-5.A " Pipe Breaks Inside Containment",
1700 025
R. H. Vollmer Noverr5er 5,1979 would also be substantially increased. We recommend that a cicar commitment to resolve this issue on a generic basis be establisned.
The Engineering Branch drafted a plan of action for resolving this issue for BWRs and we recommend this plan be implemented on an expedited basis.
Topic III-8.D not only addresses LOCA loads, but also requires the con-sideration of seismic loads. The effect of seismic loads is being considered in an overall sense under the seismic DBE review. Further-more, A-2 (and presumably the program extending this issue to BWRs) is considering the effect of LOCA loads combined with the originally defined seismic loads for each operating plant except for SEP plants.
The combination of SSE and LOCA loads for SEP plants will be resolved as part of the overall SEP evaluation. The LOCA analyses for the SEP plants will be reviewed by the Engineering Branch and modifications if required by these analyses will be incorporated as part of the SEP integrated assessment.
O*AOMlA. -
Charles H. Hofynayer,d Section Leader Engineering Section' Systematic Evaluation Program Branch Division of Operating Reactors
Contact:
K. Jabbout (28414)
Enclosure:
As stated cc w/ enclosure:
D. Eisenhut S A anauer L. Shao S. Hosford V. Noonan D. Crutchfield D. Ziemann H. Smith P. O'Cor.nor J. Wetmore T. Wambach SEP Members 1700 026
DEFIN!T*0N TOP *C:
III-8.0 Core Supports and Fuel Integrity 1.
Definition:
Abncrmal loading conditions on the core supports and fuel assemblies tue to seismic events or LOCAs could cause fuel damage due to impact between fuel assemolies and upper and lower grid plates or lateral impact between fuel assemolies ano the core baffle wall. The resulting damage could result in loss of coolable heat transfer gecmetry, make it impossible to insert control rods, or cause releases of radioactive materials due to fuel pin failure.
2.
Safe:v Objective:
To assure that all credible leading :enditions on core supports and fuel assemolies will not result in unac:e tab'e fuel damage or distortion.
3.
Status:
DOR is currently reviewing the dynamic loads imposed on the fuel assemolies during a LOCA.
Indepencent analyses are being conducted by staf f consul tants.
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References:
1.
ASME Section III 1700f 027
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