ML20236T531
| ML20236T531 | |
| Person / Time | |
|---|---|
| Issue date: | 11/24/1987 |
| From: | Leech P Office of Nuclear Reactor Regulation |
| To: | Richardson J Office of Nuclear Reactor Regulation |
| References | |
| PROJECT-669A NUDOCS 8712010338 | |
| Download: ML20236T531 (5) | |
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~Novembet 24,'1987
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' Project No. 669-11EMORANDUli FORi James Richardson, Assistant Director.-
.for Engineering'
-Division of Engineering and. Systems Technology 3
1 FROM:
Paul Leech, Project Manager Standardization and Non-Power Reactor Project. Directorate-Division of Reactor Projects III, IV, Y and Special Projects
SUBJECT:
PROPOSED REVISION'0F DRAFT SER ON EPRI_'S ALWR REQUIREMENTS DOCUMENT, CHAPTER 1 Page 4-10 of the subject Draft SER, which was issued on September 24, 1987, contains a staff position relative to the design bases for containment and ECCS.in plants for which leak-before-break. technology may be implemented under the'recent broad scope amendment to GDC-4 of 10 CFR 50 Appendix.A. At a meeting.on October ~6, 1987 with the ACRS Subcommittee on Standardization, this position (see Enclosure 1) was questioned by members of-the Subcommittee.
To clarify the meaning.of the DSER,'particularly with respect:to'ECCS, we propose to issue a revision (see Enclosure 2). This revision was suggested by Jim Brammer, who drafted the initial version that was'provided by your l
memorandum dated September 10, 1987..
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Please indicate your approval of this revision or provide a marked up. copy of.
I it with appropriate changes.
I would appreciate your responding to<this request by December 2 since this subject may be raised during the ACRS meeting on December 4, 1987.
original signed.by Paul H. Leech, Project Manager 1
87g20h0338871124 Standardization and Non-Power 80J ppR Reactor Project Directorate'
$9A Division of Reactor Projects III, IV, V and Special Projects
Enclosures:
As stated Approved:
James Richardson Date DISTRIBUTION:
CONTACT:
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November 24, 1987 Project No. 669 MEMORANDUM FOR: James Richardson, Assistant Director for Engineering Division of Engineering and Systens Technolooy L
FROM:
Paul Leech, Project Manager Standardization and Non-Power Reactor Project Directorate Division of Reactor. Projects.III, IV, Y and Special Projects
SUBJECT:
PROPOSED REVISION OF DRAFT SER ON EPRI'S ALWR RE0VIREMENTS DOCUMENT, CHAPTER 1 Pace 4-10 of the subject Draft SER, which was issued on September 24
- 1987, contains a staff position relative to the design bases for containment and ECCS in plants for which leak-before-break technology may be implemented.under the recent broad scope amendment to GDC-4 of 10 CFR 50 Appendix A..At a.
meeting on October 6, 1987 with the ACRS Subcommittee on Standardization, this position (see Enclosure 1) was questioned by members of.the Subcommittee.
To clarify the meaning of the DSER, particularly with respect to ECCS, we propose to issue a revision (see Enclosure 2). This revision was suggested by Jim Brammer, who drafted the initial version that was provided by your memorandum dated September 10, 1987.
Please indicate your approval of this revision or provide a marked up copy of' it with appropriate changes.
I would appreciate your responding to this-request by December 2 since this subject may be raised.during the ACRS meeting on December 4, 1987, a
Paul H. Leech, Project Manager Standardization and Non-Power Reactor Project Directorate Division of Reactor Projects III, IV, V and Special Projects
Enclosures:
As stated Approved:
James Richardson Date CONTACT:
P. Leech NRR/PDSNP Ext. 28209
.9mcShMe I 1
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plant-specific cases, and it would be considered for a specific ALWR design if l
the design complies with the enveloping requirement in SRP Section 3.7.2.11.4.
This section requires a comparison of the floor responses from the finite soil boundary technique with those from the half-space modeling approach, and the selection of the most conservative response.
Future modifications to the SRP may result in significant changes in this area, and the most current version of the SRP would be applied.
With respect to plant operating loads, the staff is currently evaluating the information relative to the methodology for defining the BWR safety relief valve l
loads to be used in the design of the suppression pool and will report the results when they are known.
The remainder of the information on plant operating l
loads is consistent with the staff positions on this subject.
The requirements regarding pipe rupture loads contain a statement that dynamic ~
effects resulting from a double-ended break of any pipe inside containment will not be explicitly considered in the design of the containment and emergency
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core cooling system (ECCS) for the ALWR; pipe whip, jet impingement, rapid sub-i I
compartment pressurization, hydraulic system internal loads, and the motion of m-i attached equipment will not be considered.
To be consistent with the recent Limited and Broad Scope Rule, revisions to GDC 4 relative to leak-before-break, 1.. :
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containment, and ECCS functions must still be maintained.
It is the staff's 2
current interpretation of these rule revisions that any of the above events E
that could affect the safety of containment and/or the ECCS must still be 7
included in their design bases; the containment and ECCS must continue to be
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q designed to withstand all dynamic and environmental effects from the double-1 ended rupture of the largest pipe in the reactor coolant system.
Appendix A
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should be revised to clearly state this requirement.
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In response to a staff comment relative to referencing ANSI /ANS-58.2 as providing acceptable criteria for postulating pipe breaks, EPRI agreed to revise several sentences in the Requirements Document.
Two such references on pages A-17 and A-20 will be changed to read:
" ANSI /ANS-58.2 as supplemented by applicable regulatory documents." The staff finds this commitment acceptable for defining mechanistic criteria for postulating pipe breaks.
However, EPRI also stated CH 1, SEC 4 4-10 09/13/87 Nd. IM h5
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2 plant-specific cases, and it would be considered for a specific ALWR design if the design complies with the enveloping requirement in SRP Section 3.7.2.II.4.
This section requires a comparison of the floor responses from the finite soil boundary technique with those from the half-space modeling approach, and the selection of the most conservative response. Future modifications to the SRP may result in significant changes in this area, and the most current version of the SRP would be applied.
With respect to plant operating loads, the staff is currently evaluating the information relative to the methodology for defining the BWR safety relief valve loads to be used in the design of the suppression pool and will report the results when they are known. The remainder of the information on plant operating loads is consistent with the staff positions on this subject.
The requirements regarding pipe rupture loads in Section 3.0.0.1 of Appendix A k
contain a statement that dynamic effects resulting from a double-ended break of any pipe inside containment will not be explicitly considered in the design of the containment and emergency core cooling syste'm (ECCS) for the ALWR. The dynamic effects which will not be considered include pipe whip, jet impingement, rapid subcompartment pressurization, hydraulic system internal loads and the motion of attached equipment.
It is the staff's understanding that this re-quirement is only applicable if the ALWR plant has justified the use of the leak-before-break concept. To be consistent with the implementation of the leak-before-break technology under the recent broad scope amendment to GDC-4 of Appendix A to 10 CFR Part 50, containment and ECCS functions must still be maintained. The staff's current interpretation of this rule change is that 7
any of the above dynamic effects that could affect the safety of containment
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must still be included in the containment design bases. To retain high safety g
margins, the containment must contin'ue to be designed to withstand all dynamic D__
and environmental effects up to and including the double-ended rupture of the largest pipe in the reactor coolant system. The heat removal capability of the ECCS (flow rates, pressures, storage volumes) should continue to be designed to accommodate pipe ruptures up to and including the double-ended rupture of the
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largest pipe in the reactor coolant system, even when leak-before-break is CH 1, SEC 4 4-10 11/19/87
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i demonstrated. However, ECCS hardware (piping, pumps, valves) need not be pro-l ?,'
tected against the dynamic effects of pipe ruptures in systems qualifying for
!b leak-before-breck. Section 3.0.D.1 of Appendix A should be revised to clearly d-state the above requirements.
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In response to a staff comment relative to referencing ANSI /ANS-58.2 as providing
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acceptable criteria for postulating pipe breaks, EPRI agreed to revise several I
l sentences in the Requirements Document. Two such references on pages A-17 and A-20 will be changed to reed: " ANSI /ANS-58.2 as supplemented by applicable regulatory documents." The staff finds this commitment acceptable for defining mechanistic criteria for postulating pipe breaks. However, EPRI also stated l
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CH 1, SEC 4 4-10a 11/19/87'
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