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
s 4 a-FEB 24 1978 Distribution y/6nclosure .
. Docket Fil y Docket Nos. 50-460 / LWR #3 Fire and 50-513 0. Parr M. Rushbrook l T. Cox MEMORANDUM FOR: Robert J. Bosnak, Chief,. Mechanical Engineering Branch Division of Systems Safety Stefan S. Pawlicki, Chief, Materials Engineering Branch Division of Systems Safety
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i FROM: Thomas H. Cox, Project Man;gsr, Light Water Reactors i
Branch No. 3, Division of Project Management 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 me on whether you will be able to respond by March 9,1978.
l
- 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,
- .Leg Postulation Loop Usingof 2.4 Breaks SM andin the RCS Upp(er Equations 10), Hot l (12), and (13) of MEB 3-1" r l l -- r:<.ce:
, cc w/ enclosure: J. Knight D. Tibbitts 1,~"_...;
R. Mattson W. Pike D. Vassallo S. Burwell l
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TCox:ce ~0Pa
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. . .s . 2/ 2 3 /78 2/ 23 /78 .g NRC PORM SIS (9 76) NROC 0240 W u. s.novsamment Paintine orricsa so,e-ene.sa4
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y '1d A . '.
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DML: 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 .I -
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 t Sa for all materials (El.b (l),(a)). ,
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 Sma nd if the 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 tiant 0.1. Ifnot,breaisshallbepostulated. (8.1,b (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
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l kr$ piping. If this is true, we need not postulate split breaks in the 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 y stress limit on ferritic and the use of 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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