ML20198F796
| ML20198F796 | |
| Person / Time | |
|---|---|
| Site: | Washington Public Power Supply System |
| Issue date: | 02/24/1978 |
| From: | Cox T Office of Nuclear Reactor Regulation |
| To: | Bosnak R, Pawlicki S Office of Nuclear Reactor Regulation |
| References | |
| CON-WNP-1158, RTR-REGGD-01.046, RTR-REGGD-1.046 NUDOCS 8605290095 | |
| Download: ML20198F796 (2) | |
Text
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FEB 24 1978 a-Distribution y/6nclosure Docket Fil y Docket Nos. 50-460 /
LWR #3 Fire and 50-513
- 0. Parr M. Rushbrook T. Cox MEMORANDUM FOR: Robert J. Bosnak, Chief,. Mechanical Engineering Branch Division of Systems Safety Stefan S. Pawlicki, Chief, Materials Engineering Branch i
Division of Systems Safety
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FROM:
Thomas H. Cox, Project Man;gsr, Light Water Reactors Branch No. 3, Division of Project Management i
THRU:
Olan D. Parr, Chief, Light Water Reactors Branch no. 3 Division of Project Manggement i
SUBJECT:
INQUIRY BY WASHINGTON PUBLIC POWER SUPPLY SYSTEM (WPPSS)
CONCERNING USE OF MEB 3-1 AND REGULATORY GUIDE 1.46 i
WPPSS has forwarded an inquiry (enclosed) concerning the acceptability of i
using MEB 3-1 criteria to evaluate the need for hot leg loop restraints on the reactor coolant system. WPPSS wants NRC concurrence that the pipe beeak rules of MEB 3-1 may be used for reactor coolant piping.
I Since WPPSS has both WNP-1 and WHP-4 under construction, I believe we should
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l respond with an assessment of the correctness of the WPPSS interpretation (asdescribedintheenclosure)withinacoupleofweeks. Plesse advise l
me on whether you will be able to respond by March 9,1978.
t Original Signed By:
T.caz Thomas Cox, Project Manager l
Light Water Redctors Branch No. 3 D'avision of Project Management l
Enclosure:
l Telecopy from WPPSS, dated February 22, 1978,
. Postulation of Breaks in the RCS Upp(er Hot Leg Loop Using 2.4 SM and Equations 10),
l (12), and (13) of MEB 3-1" r
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J. Knight D. Tibbitts 1,~"_...;
R. Mattson W. Pike D. Vassallo S. Burwell l
- 0. Parr C. Stahle H. Si'ver l
8605290095 780224 PDR ADOCK 05000460 LWR #3:L LWR #':BC ovvieu w
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. g 2/ 2 3 /78 2/ 23 /78 NRC PORM SIS (9 76) NROC 0240 W u. s.novsamment Paintine orricsa so,e-ene.sa4
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Febiwry 22,1978 10:-
lom Cox - NRL I.<
FRON:
A.G. llusler - WPPSS POSTULAT10NOfEREAKSINlHERCS
.e UPPER t101 LEG LOOP USINC 2.4 6 N O
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EquAT1065 (10), (12) NG (13) 0F Fift 3-1 In the WNP-1/4 PSM we connit to llegulatory Guide 1.46 which specifies the allosble stress range for ferritic steel as 2.0 Sra.
FIB 3-1 specifias an dlIUhable stre5s range Of 2.4 Sa for all materials (El.b (l),(a)).,
t further, for postulation of bre4Ls, PIB 3-1 allows calculated equation (10) stret.ses to eneed ?.4 5,,, provided, they are less than 3.0 Sm nd if the a
Cui is less thSn 0.1.
If greater than 3.0 Se, stresses calculated by.
equations (12) and (13) taken fr.dividually should be less than 2.4 % and Ct!f should be less tian 0.1.
Ifnot,breaisshallbepostulated.
(8.1,b t
(1)(b)).
I iki suth referentes tu equotion nua,bers and corresponding stress range allowi bles are n.ade in Regulatory Guide 1.46.
Also, M[B 3-1 invokes these rules soetif holly for Lies 1 piping between cont 31:icent isolation valves.
l l
We under star.J, hoaver, thdt the f4RC will allos application of the above to kr$ piping.
If this is true, we need not postulate split breaks in the
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l upper hot leg nf the Id 5 (candy cane); the hot leg bug restraints provided l
to restrun out of-plate movecent due to the split breaks my be eliminated.
l k eliminate these ii5 restraints iur E -l we need NP.C concurrence that the pipe bred rules of P.tB 3-1 cay te used for prir.ary coolant piping; specifi-telly the use of the 2.4 S stress limit on ferritic and the use of y
equ3tions (10). (12) 6nj (13).
Rules regarding nuater of break locations at types of breds will follow those listed in PIB 3-1 for Class 2 and 3 pipinc 1
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