ML20005G168

LER 89-045-00:on 891210,discovered That U-bolt Supports on Two Containment Isolation Valves in Containment Bldg Not Installed & Pressurizer Sample Lines & Valves Considered Inoperable.Missing U-bolts installed.W/900109 Ltr

ML20005G168
Person / Time
Site:	Arkansas Nuclear
Issue date:	01/09/1990
From:	Ewing E, Millar D ARKANSAS POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
1CAN019006, 1CAN19006, LER-89-045, LER-89-45, NUDOCS 9001180232
Download: ML20005G168 (4)

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= ApeL ==r R,s.elivse. AR 70831 Tet 501164 31DO January 9,1990 ICANB19006 U. S. Nuclear Regulatory Commission Document Control Desk Mail Station P-137 Washington, DC 20555

SUBJECT:

Arkansas Nuclear One - Unit 1 Docket No. 50-313 License No. OPR-51 Licensee Event Report 50-313/89-045-00 Gentlemen:

In accordance with 10CFR50.73(a)(2)(1)(B), attached is the subject report l concerning pressurizer sampling system containment isolation valves which were inoperable due to missing U-bolt seismic supports.

Very truly yours.

E. C. Ewing General Manager, Technical Support and Assessment ECE/0M/djm attachment cc: Regional Administrator Region IV U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011 INPO Records Center 1500 Circle 75 Parkway Atlanta, GA 30339-3064 j

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9001180232 900109

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Form 1062.01A NRC Fors 366 U.S. Nuclear Regulatory Coenission

, (9 83) Approved 046 No. 3150 0104 Empires: 8/31/85 L!C[N$([ [ VENT REPORT (L E R)

F ACILITY MAME (1) Arkansas Nuclear One, Unit One 10DCAET NuptER (2) IPAGE (3) 10161010101 31 11 Sl110Fl013

, M 4) Pressuciter $ampling Systee Containetnt Isolation valves Inoperable Due to Missing 2

U bolt Seiseic Supports

_ EVENT DATE (6) l LER NUa$ER (6) l REPORT DATE (7) i OTHER $ACILITIES INVOLVED (B)

I i i i 15eguentiell IRevisioni i i i i Monthi Day lYear lYear i i Number l l Number IMonth! Day (Year i Facility Names 100det Number (s) 1 I i l 1 i l i l i l i 1016 010101 1 11 21 11 01 81 91 81 91 -I Of 41 Sl+-l Of of 01 11 Of 91 91 01 1019 010101 i OPERATING l lTH15 REPORT 15 $UldlTTED PUR$uANT TO THE REQUIREMENTS OF 10 CFR tr MODI (9) i NI (Check one or more of the followino) (11)

EDWERI l_l 20.402(b) l _ l 20.406(c) l_l 60.73(a)(2)(iv) l_l'73.71(b)

LEVEll l_1 20.405(a)(1)(1) l l_ l 60.73(a)(2)(v) l_1 73.71(c)

(10) 1010101 1 20.405(a)(1)(11) l__l 50.36(c)(2) 1 60.36(c)(1) l_l 50.73(a)(2)(v11) l _1 Other ($pecify in l_l 20.405(a)(1)(111) I,Jl 60.73(a)(2)(1) l_ l 60.73(a)(2)(v111)(A)l Abstract below and l_ l 20.405(a)(1)(iv) l_ I 60,73(a)(2)(11) l_l 50.73(a)(2)(v111)(B)l in Text. NRC Form I i 20.40$(a)(1)(v) l l 60.7Fe)(2)(111) 1 l s0.73(a):2)(x) i 366A)

LICENSU CONTAC) FOR TMls L :R (12) home l Telephone Number lArea i Dana Miller, Nuclear Safety and Licensing Specialist iCode i 1610111916141 13111010 COMPLETE ONE LINE FOR E ACH COMPONENT F AILURE DESCRIBE 0 IN THl$ REPORT (13) i i l IReportablel I i i l IReportabiel Causelsysteel Component IManufactureel to NPR0$ l ICausel$ysteel Component lManufactureel to NPR0$ l 4

1 l l i i l i l i l i 1 1 1 I I I l l i l i l I i i l I i l ! I I I I i 1 l i l l i l i i i ~l i I I I I I I I I i 1 I I I i i I I i 1 i I 1 i SUPPLEMENT REPORT EXPECTED (la) i EkPECTED l Monthi Day Ivear i SUBMI$$10N l l l

_ l'l Yes (If ves. complete Expected submission Date) III No I DATE (15) l I I I I I ABSTRACT (Limit to 3400 spaces, i.e., approximately fifteen sing 1** space typewritten lines) (16)

On December 10, 1989, while inspecting pressuriter sample lines and associated hangers in preparation of replacing two containment isolation valves located in the containment building, it was identified that U bolt supports which were shown on detail drawings were not installed on the containment isolation valves. Additionally, a spring hanger was found not installed. Based upon an engineering judgement, the pressuriter sample lines and isolation valves were considered inoperable due to the missing U-bolts.

The missing spring hanger did not affect operability of the piping or isolation valves. While replacing the valves, the U bolts were reinstalled. The pressuriter sample lines are designed as Seismic Category 1.

Had a seismic event occurred, a small Reactor Coolant System (RCS) leak and small RCS depressurization may have occurred if the piping had ruptured. Containment isolation would have been maintained by the external solenoid operated valve which is normally closed. Therefore, the health and safety of the general public would be assured and the safety significance minimal. A review of previous maintenance activities anti plant modifications associated with the two valves did not indicate that the U-bolts had been removed previously. It appears that the U-bolts were removed during a maintenance activity or construction and not reinsta11ed. This condition is reportable per 10CFR50.73(a)(2)(1)(B).

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.- i F?m 1062.01B NRC fem 366A U.S. Nuclear Regulatory Commission  :

(9-83) Approved OMB No. 31b0 0104 I s Expires: 8/31/85 LICEN$tt (VtNT REPORT (LER) TEXT CONTINUATION F ACILITY MMI (1) lDOCMT NUMBER (2) l LIR NUMBER (6) lPAQt(3) l i i l$eguentiall (Revisioni -

)

Arkansas Nuclear One, Unit Une l l Yearl Number i Number i 10l$1010101 31 Il 31 Bf 91-- 01 41 br-- 01 0101210Fl013 TEXT (If more space is required, use additions 1 NRC form 366A's) (17) l A. Plant $tatus At the time of discovery of this condition, Arkansas Nuclear One Unit One (AND*1) was in Cold

$hutdown. A mid-cycle maintenance cutage was in progress.

B. Event Description There are two sample lines from the pressuriser, one providing a means of sampling the pressuriter sample space and the other line a means to sample the pressuriter water space, tech sample line has a motor operated containment isolation valve located inside the containment building which is normally closed (CV1814 and CV1816). The sample lines join together and pass through the containment building where a nomally closed solenoid operated valve is located which provides the outside cuntainment isolation for the penetration. The pressuriser sample lines are designed and constructed as Seismic Category 1.

On December 10, 1989, as part of the normal pre-installation walkdown process in preparation for a plant modification to replace CV1814 and CV1816, it was identified that seismic U-bolt type supports which were shown on the applicable design drawings were not installed on either valve.

Additionally, a spring hanger located near CV1814 was found not installed.

Based upon Engineering judgement, the pressurizer sample lines and associated inside containment isolation valves were considered to be inoperable due to the potential for failure as a result of a seismic event. This determination is based on a relatively large concentrated mass volume (i.e.

i weight of motor operated valves) versus the small pipe size (approximately one half inch) at the missing U-bolt locations. The missing spring hanger did not impact the operability of the piping or the isolation valves.

C. Safety Significance The pressuriter sample lines are designed as Seismic Category !. With the missing U-bolt hangers, the ability of these lines to remain structurely intact during a seismic event could not be assured. Therefore, had a seismic event occurred the pressurizer sample lines may have ruptured creating a non-isolable path from the pressuritte. If both of the pressuriter sample lines were  ;

to rupture as a result of a seismic event, a small depressurization and a small Reactor Coolant  !

$ystem (RC$) [AB) leak would occur. The small amount of leakage would be well within the capacity of the normal RCS makeup pumps. Containment isolation would be maintained with the outside solenoid operated valve which is normally closed. The outside containment isolation valve is  !

opened for short periods of time only during sampling, Although a small RCS leak could have been created if a seismic event had occurred, the reactor building is designed to contain the radioisotopes associated with the RCS and protect the health and safety of the general public. Therefore, the I safety significance is minimal.

D. Root Cause j

The root cause of this event could not be conclusively detemined. A review of previous maintenance l activities as:ociated with CV1814 and CV1816 did not indicate that the U-bolts were removed to l assist in the performance of any maintenance activity. A review of previous plant modifications l was also performed which did not identify any modifications to the missing U-bolt supports.  !

However, remnants of the old supports were found to be installed and it was concluded that the l supports had been installed during initial plant construction. It appears that during the performance of a maintenance activity or during construction the U-bolts were removed and not reinstalled. It could not be determined if the missing spring hanger had ever been installed.

E. Basis for Reportab111ty I The inside containment isolation valves for the pressurf ter sample lines were considered inoperable upon the discovery of the missing U-bolts. Since it can not be detemined how long the isolation valves had been inoperable, it has been assumed to be for a time period greater than that allowed by Technical Specifications. This condition is, therefore, reportable pursuant to 10CFR$0.73(a)(2)(1)(B), operations prohibited by Technical Specifications.

e Form 1062.01B NRC Form 366A U.S. Nuclear Regulatory Commission (9 83) Approved DMB No. 3160 0104

[xpires: B/31/85 LIC[N$(( [V[NT REPORT (L[R) T[KT CONTINUATION FACit!TV NAME (1) 100CAET NUMBER (2) l L(R NUMbfR (6) l FAG [ (3) l l l 15eguentiall IRevisioni Arkansas Nuclear One, Unit One l l Yerrl I Number I I Number l 1015f0f0f01 31 Il 3f el 91--I 01 al bl -I 01 0101310F10f3 T[KT (If more spect is required, use additional NRC Form 366A's) (17)

F. Correctise Actions During the mid-cycle maintenance outage CV1814 and CV1816 were cut out and replaced. As part of this modification the missing U bolto were installed. It was determined that the spring hanger was not required for seismic considerations and this hanger was not reinstalled. The load setting on a similar support located near the missing spring hanger was increated to ensure the loads emerted by the piping would De adequately supported.

Additionally, an Isometric Drawing Update Project, which is designed to identify and resolve existing discrepancies between safety related piping isometric and hanger drawings and the as* built condition of the plant is ongoing and should identify any other deficiencies associated with Seismic Category I piping systems.

G. Additional Information Previous similar events in which missing seismic supports rendered components inoperable were reported in 60 313/87 001-00, 60-313/88-011-01, 50 313/89 013 00 and 50 313/t.9 016 00.

[nergy Industry Identification System Codes ([115) are identified in the text as (XX).

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