ML20084K022

AO 1-72-4:on 720404,during Shutdown Insp,Damaged Pipe Hangers & Seismic Restraints Discovered on RHR Sys.Caused by Improper Venting.Restraints & Hangers Repaired & Venting Procedure Modified

ML20084K022
Person / Time
Site:	Quad Cities
Issue date:	04/11/1972
From:	Palmer F COMMONWEALTH EDISON CO.
To:	Morris P US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084K002	List: ML20084K022 ML20084K040
References
AO-1-72-4, FAP-72-84, NUDOCS 8305190121
Download: ML20084K022 (2)

Text

o - - -

} '. 3% p 72 m s*-sts' pp6 -84 0-

?

. g.n

.: .; ,n

^

~ \

t .

i , ". ;/j j Commonwealth Edison Company Q U A D-C ITIE S NUCLEAR POWER ST ATIO N

] Address Reply to:

I POST OFFICE 80X 216

• CORDOVA, ILLINOt$ 61242 l, .r.,

1 /

3 O t

' ~-

April 11, 1972

[s ,

1 Dr. Peter A. Morris, Director Ol97 g d e%r /

Division of Reactor Licensing At U. S. Atomic Energy Commission '

Washington, D. C. 20545  % d,,

~ ty . -

Subject:

License DPR Quad-Cities Nuclear Power i

Station Unit #1 Section 1.0A4 and Section 6.6B2 of the Technical Specification

Dear Dr. Morris :

This is to report a condition relating to the t

operation of Quad-Cities Nuclear Power Station in which, during a routine inspection, seismic restraints and pipe hangers on the residual heat removal system were found to be damaged.

Description - On Tuesday, April 4, 1972, at approximately 10:00 a.m. while the reactor was in the shutdown mode, a damaged pipe restraint was reported to the Unit 1-Operating Engineer. The restraint is located on line 1-

1086-6" at 595' elevation, line 1-1096-6" the tie between j the residual heat removal system (RHRS) and the fuel pool cooling system. Visual inspection of the RHRS system revealed the following:

1) 1 - Seismic restraint on line 1-1099- damaged.

2) 2 - Spring hanger bottomed on line 1-1009- -

3) Grout chipped on seismic restraint on line 1-1009

4) MO-1-1001-23B would not open electrically.

!Jf/P' t

5) 2 - Seismic restraints damaged on line 1-1086  :

c(#S 6) 4 - Hangers damaged on line 1-1086

{ft u c

&& 5p' y! ,

Qh) 8305190121 720412 Q(N 4 by.[DR ADOCK 05000254 ,

PDR < ,

Qfi; ,

9 **

f n.

\

7 E

,a _ 2 COPY SENT REGION

o

.o

.Dr. Peter A. Morris April 11,1972 Cause - The cause of the incident is believed to be improper venting with the resultant water hammer. The filling and venting procedure requires use of the jockey pump as a water supply and an operator venting from the avstems pipine high points until a solid water flow is observed. The venting at high points only leaves several possible points for air accumulation as follows:

Upstream from all four discharge check valves; and the tie line to the fuel pool cooling system. When the "A" RHP pump was started on Sunday, April 2, 1972 for a modification test a noise was reported by an engineering assistant in the technical staff working in the area, but no damage was noted at the time.

Analysis - Piping specialists from Sargent and Lundy were called to the station to evaluate the damage and to assist in directing the repair. After walking the system and measuring displacements , a computer analysis was performed. The results indicated that no piping or welds were overstressed. Three welds that were in the highest stress area were dye checked with no defects observed.

The damage was caused by water hammer. The system was in

, an operable condition and could have performed its intended function.

The motor operated valve MO-1-1001-23B containment spray failed to open electrically because of mechanical failure of the motor housing which caused the brake to engage. The valve could be operated manually.

Repair and Corrective Action - Seismic restraints and pipe hangers were repaired under the direction of the General Electric Company following approval procedures. The filling and venting procedure was altered so as to use the condensate-transfer system as a water supply for filling. The condensate. transfer system provides a larger flow and higher.

pressure than the jockey system that was used in the old procedure. Following the repair the new filling and venting procedure was used and the system tested with men located at all RHRS piping areas. The system was started with no signs of any water hammer. The motor operated valve MO-1001-23B was repaired and tested satisfactorily. I Very truly yours, l

a: COMMONWEALTH EDISON COMPANY f; Quad-Cities Nuclear Power Station

.s 4ff yy"- ^

I ser .mm F. A. Palmer RPi[N. -

Superintendent n

• 53?/wm

.