ML20009A922

Interim Deficiency Rept Re RCS Attached Piping,Originally Reported on 801113.B&W Analyses Determined That Potential Breaks at Pump Nozzles Will Not Result in Subsequent Breaks in Piping Adjacent to Pumps.Repts Will Be Sent Quarterly

ML20009A922
Person / Time
Site:	Washington Public Power Supply System
Issue date:	07/02/1981
From:	Mazur D WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	Faulkenberry B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
10CFR-050.55E, 10CFR-50.55E, GO-1-81-198, NUDOCS 8107140497
Download: ML20009A922 (3)

Text

e" 50.55(e) Report Docket Nos. 50-460/513 g

Washington Public Power Supply System P.O. Box 968 3000 GeorgeWashingtonWay Richland, Washington 99352 (509)372-5000 Nuclear Regulatory Commission July 2. 1

~f 67 4

Region V G0-1-81 IS Q N Suite 202 Walnut Creek Plaza M

IRCFNL

.Y,g[g" i Jul G 1981 _

1990 N. California Boulevard riL u *

.b acten v Walnut Creek, California 94596

[J M

INSPECTION & D JUb l 3 LO8N

[

Attention:

Mr. B. H. Faulkenberry J

Chief, Reactor Construction 7 "'8"goowee h

Projects Branch sc p

Subject:

PROJECTS 1 AND 4 V

DOCKET NOS. 50-460 AND 50-513

'Wl#

POTENTIALLY REPORTABLE CONDITION 10CFR50.55(e)

RCS ATTACHED PIPING

References:

1)

Telecon TJ Houchins, Supply System to DF Kirsch, Region V Nuclear Regulatory Commission dated November 13, 1981 2)

G0-1-80-380, dated December 12, 1980, DW Mazur to RH Engelken, Director In reference 1) the Supply System informed your office of a potentially

/

reportable deficiency under 10CFR50.55(e) and reference 2) was an interim report on the subject condition.

Attachment A includes a restatement of the identified condition and a brief description of our planned and on going actions to evaluate the condition. Due to the nature and extensive amount of time necessary to complete our design analysis we hve concluded that this is a reportable condition in accordance with paragraph (IV) of 10CFR50.55(e). Thus in keeping with refnence 2) we are submitting Attachment A as an interim report. However, it is impossible, at this time, to provide a final completion date for the subject design analysis. Therefore the Supply System will provide your office with interim status reports on a quarterly basis.

If you have any questions or desire further information, please advise.

Very truly yours, D. W. Mazu Program Director WNP-1/4 CWM:MER:lm Attachment cc: CR Bryant, Bonneville Power Administration /399 49 8107140497 810702 PDR ADOCK 05000460 S

pop I

$Ob

Attachment A Wlp-1/4 Docket Nos. 50 450 and 50-512

~

Reportable Condition 10 CFR 50.55(e)

(Fotential) Reactor Coolant System Attached Piping Second Interin Report BACKGROUND In GO-1-30-38 dated 12/iE/SO, the Supply System provided a report on this subject to the NRC. This report concluded that the concerns sterminc frc, analysis cerformed cn piping attached to the RCS represented a cotentially reportable conditicn and that a report would be provided in the second quarter of 1981.

The purpcse cf this letter is to apprise the NRC of our on-going program and the results to date.

DESCRIPTION OF DEFICIENCY B&W originally reported a concern for the ECCS analysis performed which assumes that the piping connected to the RCS loop in which the LC,CA pipe break is assured to occur remains intact during the event.

ELW had not analyzed several lines to detenaine if these assumptions are correct.

In addition, B&W reccomended that the balance'of the RCS attachment piping analyses be reviewed to confirm that the basic analytical techniques used are conservative and that the piping is adequately

csignei to caintain function and integrit; under LOC: c er.d i ti o ns.

..:e tr e a i gi a'.

re o:rt,

5:,'..' b a s :er 'O rne: accitic ai ar.al ses ina :st r ine:

c "cr the react:r cc:iant pvp sucticn and disinar;e c' pin; that p::ential treacs it tne ;np nozzies uiii not resuit in subsequent breacs in :ne react;< coolant piping adjacent to the pumps.

Likewise, the pressurizer surge-line analysis has

'been completed' and the results demonstrate that this line (attachment to hot leg oiping) is not of concern. The remainder of the piping analyzed by B&W is still under;cin; evaluation.

The A/E for..NP-1/c, United Engineers and Constructors (L' ESC), perfor~ed a review cf all owners su:piied RCS at:achment oiping and confi-r.ec that a Less cf Coolant Accident Anchor Disolacement Analysis (LAD) had been performed.

Further investigations have raised questions, whetner the Static Displacement "ethod (SDM) which was utilized in the analysis is conservative. The original

2' analysis utilized, as inout, static values over acclicable LOCA breaks which contributed to the anchor displacement at the terr.inal end of the pipe run.

Historically, this approach has been consistent with standard industry practice and believed to be conservative.

As a result of tnis curren; effcrt, dynamic ana'.yses nave been perfor ed in orcer to demonstrate that the original SDM is conservative.

Using worst case time history displacements selected by B&W, a time history LAD analysis was performed for a line in the Decay Heat System (DHR-4-1-14) and Main Stean System (MSS 3-1-28).

The results are as follows:

1.

The combined pipe stresses (. including LOCA and o.ther loadings) did not increase sicnificantly and remained within the allowable limits.

_=

E.

, {T

&I

~

~

Attachment A Page Two m

2.

Pipe s0pport loads increased significantly, in some cases up to 30 to 50

.=

percent.

To date, two supports (DH?.) have been determined to have leadings which exceed the design allowables.

3.

The component nozzle loads were also determined to increase significantly.

The DHR nozzle loads exceeded B&W allowable limits, whereas, the MSS nozzle loads were within B&W allowable limits.

ELW is currently evaluating the increased DHR nozzle loads for acceptability.

Although the design allowables are exceeded for the pipe supports, this loading only occurs under faulted conditions.

The loadings calculatec do not exceed f aulted allowable loads for the supports, however, it.will result in ceflecticas of those supports.

Since the original piping analysit was perforred without e>.ceeding design conditions for supports and hence, no deflection, any new analysis which assumes support deflection will result in higher values for pipe stress.

SAFETY IMPLICATIONS Although these two pipe supports would not fail under these revised Icading conditions, the loading placed on the piping as a consequence of the support deflection could result in unacceptably high stresses.

It has not yet been deternined that this is the case.

Ein:s :ne :rar ic Ana',jsis perf:: ec.5s s :.r a signi#i:in; c ease

, i:ic c.er

~

the tre'.ious Static Distlacement Methcd anc the scce:-tab' it e :f :he :i:in: in :he

-~.i aity cf the t.-o supports '..hich nave been de:er-ine: :c he : vers essei (cesign allcwables) cannot be assured without further analysis, it is determir.ed that this is a reportable condition under paragraph (ivl of 10 CFR 50.55(e) since extensive analysis is reouired.

.. CF RECTI"E ACTION PLANNED As a result of analyses perforr.ed to date, it will be necessary to re.iew/reperform analyses for all attachment piping to the RCS te determine whether dcsign conditions are ex.ceeced folicwing an accident.

For those cases where design all:wable loadings are exceeded, it will be necessary to perform additional evaluations to determine whether hardware modificatiuns are required.

It is not possible, at this time, to provide a final completion date. The Supply System will provide interim status reports to the NRC on a quarterly basis.

,=

v

~

/

.