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W e-May 24, 1976 ACRS ACRS Technical Staff i
MEETING ON MIDLAND 1&2 PROPOSED HIGH ENERGY LINE BREAK ANALYSIS On May 21 Consumers Power Company met with the NRC Staff in Bethesda to discuss proposed High Energy Line Break Analysis (HELBA) for the Midland Units. The Agenda for the meeting (attached) appeared of sufficient interee': to ACRS that, with Mr. Libarkin's concurrence, I attended.
t The meeting had been requested by Consumers Power Company (CPCo.),
not to negotiate around requirements but to get an interpretation of requirements from the Staff in view of newer Standard Review j
Plans (SRP) since the Midland application was filed. Rechtel had l
indicated that $30 - 50 million was at stake cost-wise, and schedule-wise. They were approaching the critical pouring of concrete and needed answers to finish the work.
l Representatives of CPCo., Bechtel, and B&W were present. The Staff was represented by the LPM, Larry Crocker, and the Mechanical l
Engineering and Auxiliary Power Conversion Branches.
The Roman numerals below refer to the corresponding agenda items:
f I.
The CPCo. HELBA system consists.of analysing all piping within a set of anchors as one system. Each system may have several branch runs but it reacts as a system. All stresses calculated are low compared to Regulatory Guide 1.46 (.8 yield).
Inter-mediate points are picked for analysis on the basis of highest stress, but none exceed the.8 criterion.
A system may have four anchor points or terminsi ends; breaks are postulated there. The following example was used:
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gx, d = anchor Break at each of anchors and anywhere stress exceeds.8 (No where) l I
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l Regulatory Guide 1,46 may require break at terminal 0, but this Tee does not act as a restraining point since there is no anchor there.
The NRC Staff indicated they would have no problem with not postulating a break at this point provided a detailed stress snalysis is done at this point to show that no strees limits I
are exceeded.
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The same concept applies to all HgLBA i
II.
It was agreed that longitudinal slot breaks at terminal and points need not be assumed (except for seemed piping).
CFCo.
pointed out that this is inconsistent with commitments made in their Amendment 25.
Nevertheless, Mechanical Engineering Branch (MZB) representatives found this acceptable for Class 2 l
and 3 piping.
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III. It was agreed that longitudinal slot breaka need not be
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postuisted to occur at intermediate locations. Only circumferential breaks are assumed since the.8 criterion j
is not approached.
It was noted that guard pipes may be a problem. They must l
be subject to in-service inspection (ISI).
IV.
The referenced letter required a discussion of the effects of l
critical cracks in high energy systems. A " critical crack" j
is defined as one half the pipe diameter in length and half the wall-thickness in width. Full area breaks are calculated only l
where both 2000F and 275 psig are exceeded. The Staff asked if a critical crack can affect a piece of safety eq'uipment. CPCo.
e pointed out the piping was so lowly stressed that there was no reason to consider it.
The Staff concurred that longitudinal j
cracks need not be considered for high energy piping. For moderate energy, critical cracks should be cassidered; however, any adverse situation will probably be taken care of by the postulated break in high energy lines.
It was agreed that item 3 in the schwencer letter (a copy of which was not available) was taken care of. The Applicant will I
consider H.E. cracks of short duration.
The agreement that Moderate Energy (M.E.) Analysis was not required, V.
seemed clearer in the Bechtel meeting notes of the September 11, 1973, meeting, than in those prepared by NRC. The Staff indicated cracks in M.E. systems must be examined to insure that redundant safety i
systems are not impaired. The Staff would be satisfied if lines j
close to safety systems are identified and only those analyzed.
If a M.E.
line is close to a limitine H F-lina. the MW. line need i
not be analyzed.
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CPCo. indicated the M.E. Analysis might not make the FSAR.
CPCo. will plan to do M.E. line analysis but will reserve the option to bring in problems for further discussion.
If a conflict arises between the SRP and Amendment 25. CPCo.
will use the SRP.
CPCo. stated that the requirements were clarified and that the meeting had served its purpose.
/s/
Regnwald Muller Senior Staff Assistant i
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,IS pFl. AD HTCil E'IERCY 1.INE BREAK AMAi MEETING AGENDA Interpretation cf piping runs, branch runs, and terminal end points I.
We propose that piping runs and branch runs for piping inside and outside containnent be treated as a total piping system between fixed points (anchors) since the stress analysis performed considers and seismic stress it as such. Ue perf arm thermal, dead weight,
(within anchors).
total system including branch lines analyses for the The annlysis considers all of the stress intensification factors and flexibility f actors as applicabic to various piping components.
Thus, va propose that brechs be postulated within the system as follows:
Terninal end points (anchors)
(Branch connections to main piping are not considered as 1.
terninsi ends.)
At all points ubich eneced the stress criteria of R.G.1.46 (2) interuediate brechs will be celected 2.
for each pipir; syster.,0;.ain and branch lines within anchors 3)
(As a nininua, tuo teruinal end points II.
Longitudiral slot brecur at that longitudinal slot brents not be postulated to occur This at ter-in:1 cad points for piping uithout longitudinal walds.
We props.:
proper 1 is in accordance rith Section 3b(2)(a) of the Eranch Technjeni Position M'.B 3-1 cnd should be a reasonable acsumption for Midlcnd l' nits 1 rr i 2 both inside and outside of contalu.?.2nt.
Icngitedinal clot breaks at intercediate locationc III.
longitudincl slot breaks not be postulated to occur Ue prorcse that at internedinta locations uhere the Regulatcry Guide 1.45 criterior This for a mini.au nunber of brcsh locations nust be satisfied.
in necc rdance with section 3b(2)(b) of the Branch proposn3 it.
3-1 and should be a reasonable assumption Technicel Pos' t i on Mr.'
1 cud 2 both incide and outside contcinment.
for Midland Units Discussir'n of iten 3 of A. Schuencer (UnC) to S. Howell (C 25 to the Midla..
IV.
let ter of October 18, 1974, pcrt aining to Anende :nt PSAR.
Moderate Energy Analysis V.
Based na arre ments reached in the r.ccLing uith the NRC on Septenbe is our underutanding that mod r tte energy un' lysin ic e
11, 3973, it not required for Midland.
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