ML20151L207

Lists Tasks Planned by Mechanical Engineering Branch Which Respond to 850723 Briefing Request to Investigate Adequacy of PWR Main Steam Safety Valve Testing & Value of Extrapolating Test Data from Small Valves

ML20151L207
Person / Time
Site:	Seabrook
Issue date:	09/27/1985
From:	Bosnak R Office of Nuclear Reactor Regulation
To:	Crutchfield D Office of Nuclear Reactor Regulation
Shared Package
ML20151L176	List: ML20151L171 ML20151L207 ML20198E649 ML20198E674 ML20198E681 ML20198E699 ML20198E704 ML20198E709 ML20198E717 ML20198E724 ML20198E744 ML20198E762 ML20198E798 ML20198E805 ML20198E810 ML20198E815 ML20198E822 ML20198E845 ML20198G507 ML20198G700 ML20199F528 ML20199F532
References
FOIA-86-266 NUDOCS 8510030021
Download: ML20151L207 (4)

Text

_ _ - _ _ _ _ - - _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ - _ _ _ _ _ _ _

sy va o,, UNITED STATES 8 o NUCLEAR REGULATORY COMMISSION

7. RE WASHINGTON, D. C. 20555

\....+/ -

MEMORANDUM FOR: Dennis Crutchfield, Assistant Director for Safety Assessment Division of Licensing FROM: Robert J. Bosnak, Acting Assistant Director for Components and Structures Engineering Division of Engineering

SUBJECT:

JULY 23, 1985 OPERATING REACTOR EVENTS BRIEFING OPEN ITEM - INADEQUATE MAIN STEAM SAFETY VALVE CAPACITY AT SEABROOK At the Operating Reactor Events briefing on the subject issue on July 23, 1985, DE was asked to investigate the adequacy of testing of PWR main steam safety valves (MSSVs) and the validity of extrapolating test data from small valves to larger full size MSSVs. The Mechanical Engineering Branch (MEB) has planned the following tasks which we think adequately respond to this request:

(1) MEB has prepared a proposed IE Information Notice to advise the industry of the MSSV capacity problem as it relates to proper ring settings. The proposed' Notice was transmitted to DL with our August 9,1985 memorandum from R. Bosnak to D. Crutchfield.

. (2) MEB will fomally request DST to prioritize a potential generic issue dealing with MSSV operability problems including that of inadequate flow capacity. The procedure outlined in Office Letter No. 40 will be followed.

(3) MEB will discuss with the AStiE Section III Subgroup on Pressure Relief possible changes to the ASME Section III Code Class 2 safety valve certification requirements. Currently CL. 2 safety valves can be capacity certified based on tests performed on prototypical valves much smaller in size and at much lower pressures than are applicable for PWR, Main Steam e Safety Valves. The ring adjustment problem encountered with the Seabrook MSSVs raises one of the same questions that arose during the recent EPRI testing of ASME Section III CL.1 pressurizer safety valves. That is, do the valve manufacturers have an adequate understanding of how to extrapolate ring adjustments, that affect lift and blowdown, from very small test valves to the very large safety valves used on PWR plants?

Recently changes to the Code safety valve certification procedure, proposed by MEB, to address this concern for CL.1 safety valves were accepted by ASME for. incorporation into the Code. The change will require that new CL. I safety valve designs be prototypically tested in sizes and at pressures, temperatures, and flow rates that envelope those that the valve design will be used for in service. .

MQY

1. u # a/n

Dennis Crutchfield - MEB will explore with the Code Committee the feasibility / desirability of making similar changes to the Code CL. 2 safety valve certification requirements.

We believe these actions should adequately resolve the problem of inadequate MSSV capacity.

ob J. Bosnak, Acting Assistant Director for Components and Structures Engineering Division of Engineering cc: Jf Knight vF. Cherny B. Sheron G. Holahan D. Tarnoff R. Baer H. Gregg O

O O

.-- -.--- - -- - - - , , - - . , - , - - - - - - - - - - , - -- - - - - - - - , . - - - - . - , ...-w.---. ., - y,,.. ,. .---. , , -, - , - ... n ,,. -, -- -- - -.-- -

A

. k

[g =l }

r] I(/f/

y lQ /k 0 3fdLLAs -

-1 de&dua=np&w e

aq e--jys u *m,4,,a t I e

G B

B G

- - - - -.- - - - - - - - - - , - - - - - - . . - , - - - - - , , . - , .n- ,n.,- ,.---,e + , - - - - , - . - , .- , , , -,-w n.,- . , -----

4 9g G # e 4

\)p n e. . tjj, Qn w' i 2-Cf6-x w e

• • • e ,

9

, r f ;u G .

, N hs ' k. --t- .+ /ff?. .

[ i ,7 &, ,

b.rar-,.?

DJ fa  % gu f a.ad y

. . . ~ de ,

e e i

- d Jl

• b %r / , ,

, O ***

O

• l _. O o p

• .2 u ,o e

,e 6 A/

}

• W r

.l1

?

~/} l sI

=y- / --- . . -

\

. [ D ?> ' k. -:

} Y 't l

1. A