Part 21 Report - 1995-082
ACCESSION #: 9503300325
INITIAL 10CFR21 NOTIFICATION
ANCHOR-DARLING CHECK VALVE HINGE ARMS
PUBLIC SERVICE ELECTRIC & GAS CO.
HOPE CREEK GENERATING STATION
DOCKET NO. 50-354
Public Service Electric & Gas (PSE&G) has determined that a Substantial
Safety Hazard could exist regarding the subject deficiency in accordance
with the requirements of 10CFR21. Therefore, PSE&G is reporting this
deficiency to the NRC in accordance with 10CFR21.
This Part 21 evaluation documents a deficiency in Anchor-Darling check
valves due to incorrect dimensional tolerances of valve components.
Specifically, 12" Core Spray Pump "B" discharge check valve (1BEV-015)
failed to close during performance of surveillance procedure HC.OP-IS.BE-
002(Q) in November, 1994. Inspection of the valve determined that the
valve disc contacted the body in such a way as to pinch the disc, causing
it to stick in the open position. The valve design includes a butt stop
hinge to prevent the disc from contacting the valve body. Based on the
inspection, it was determined that the butt stop on the hinge arm was not
of sufficient length to contact the valve body and prevent disc-to-body
contact (See Enclosure 1 - valve cross-sectional drawing). To correct the
deficiency, a new butt stop hinge arm, hinge pin and disc were installed,
and the valve was successfully retested in accordance with the
surveillance test procedure.
As a result, PSE&G initiated inspections of Anchor-Darling check valves
with a similar hinge style to determine if a generic deficiency exists.
A total of fifteen (15) additional valves may be affected. On 1/19/95,
20" Safety Auxiliaries Cooling system (SACS) pump discharge check valve
(1EGV-019) was inspected as a result of the Core Spray check valve
failure corrective actions. The inspection revealed that the valve disc
was knocking against the valve body in two places with the valve in the
open position. The valve hinge arm and disc were replaced, and the new
hinge arm was modified per the vendor instructions to build up material
on the butt end.
The SACS check valve was equipped with the butt stop hinge design, and a
small non-functional tail stop. This hinge was different from that shown
on the design drawing which reflected a butt stop design only. The
current design drawings for the sixteen (16) Anchor-Darling check valves
reflect only the hinge butt stop design. Therefore, the small tail stop
noted above was not consistent with the current design drawings.
Page 1 of 4
INITIAL 10CFR21 NOTIFICATION
ANCHOR-DARLING CHECK VALVE HINGE ARMS
PUBLIC SERVICE ELECTRIC & GAS CO.
HOPE CREEK GENERATING STATION
DOCKET NO. 50-354
PSE&G's evaluation of the check valves has determined that this issue is
not considered an immediate operability concern for the following
reasons:
- Only one previous Anchor-Darling check valve (Fuel Pool Cooling &
Cleanup (FPCC) Pump discharge check valve 1ECV-007) of similar design was
found stuck in the open position due to the hinge butt pinching against
the body. This occurred on three (3) separate occasions in 1988 and
1989. The final resolution was to grind the hinge butt. No problems to
date have been identified since the corrective actions were completed.
- Successful completion of respective check valve surveillances, no other
identified instances of disc-to-body contact, and overall history which
demonstrates that the valves are not prone to failure.
- No disc pin failures have been identified. Our evaluation of this
dimensional tolerance deficiency has revealed that fracturing of swing
check valve disc pins has occurred in the industry. These have been
attributed to the direct impact of the valve disc on the body during
opening. Repeated occurrences of this impact due to operation and/or
disc flutter have caused the disc pin failures. Anchor-Darling modified
its swing check valve design by adding an extended hinge tail stop to
absorb the impact during valve opening. (Refer to Enclosure 2 - Anchor-
Darling product literature.) This modification addresses the potential
disc pin failure concern. Anchor-Darling has recommended replacement of
the older design. The disc pins that were removed from both the Core
Spray Pump "B" check valve (1BEV-015) and SACS Pump check valve (1EGV-
019) were visually examined, and no disc pin defects were identified.
An evaluation has determined that this specific Core Spray check valve
failure would not have resulted in a Substantial Safety Hazard as defined
in 10CFR21. The Core Spray check valve failure would have rendered one
Core Spray loop inoperable. Should a single failure be considered
concurrently in accordance with 10CFR21, both loops of the Core Spray
system could be inoperable.
Page 2 of 4
INITIAL 10CFR21 NOTIFICATION
ANCHOR-DARLING CHECK VALVE HINGE ARMS
PUBLIC SERVICE ELECTRIC & GAS CO.
HOPE CREEK GENERATING STATION
DOCKET NO. 50-354
However, the design of the Emergency Core Cooling Systems (ECCS) would
ensure that a sufficient combination of ECCS equipment (i.e., three (3)
Low Pressure Coolant Injection (LPCI) loops and the Automatic
Depressurization System (ADS)) would be available in the event of a Loss
of Coolant Accident (LOCA) even if offsite power was not available (See
Hope Creek UFSAR Subsection 6.3.1.1.2).
A list of the sixteen (16) Anchor-Darling check valves with the similar
hinge arm design, which rely on the butt stop, is provided in Attachment
1. A review of selected additional hinge arms in storage showed either
no tail stop or the non-functional older hinge arm tail stop. The hinge
arm that contained a small non-functional tail stop appears to be part of
the older design, although not reflected on the design drawings. These
hinge arms rely on a butt stop to prevent disc to body contact.
PSE&G has concluded that the use of the older hinge arm design, which
relies on the butt stop, may not preclude disc-to-body contact (as was
the case with the Core Spray and SACS check valves). This may result in
disc pin failure or the potential for the valves to stick in the open
position. A failure of the SACS pump discharge check valves could affect
the cooling water supply to the Residual Heat Removal (RHR) Heat
Exchangers, Control Room Emergency Filtration (CREF) chillers, Emergency
Diesel Generators (EDG's) and EDG room coolers, Filtration Recirculation
ventilation System (FRVS) cooling coils, FPCC Heat Exchangers and the
ECCS Pump Room coolers. A failure of the RHR Pump discharge check valves
could affect Low Pressure Coolant Injection following a LOCA and long-
term decay heat removal capability post-accident. Based on the above,
PSE&G has concluded that the existing hinge arms installed at Hope Creek
are considered a Substantial Safety Hazard as defined by 10CFR21.
Therefore, this issue is reportable in accordance with 10CFR21.
Inspection of the remaining valves to determine if similar dimensional
tolerance deficiencies exist, and replacement of the hinge arms with the
extended tail stop design, is being planned. Design Change Package (DCP)
4HO-0916 will install the extended hinge arm design on the sixteen (16)
affected valves. The estimated schedule for replacement work to begin is
the 3rd Quarter of 1995 based on the results of the remaining
Page 3 of 4
INITIAL 10CFR21 NOTIFICATION
ANCHOR-DARLING CHECK VALVE HINGE ARMS
PUBLIC SERVICE ELECTRIC & GAS CO.
HOPE CREEK GENERATING STATION
DOCKET NO. 50-354
inspections. This will allow sufficient time to prepare the DCP and
obtain the necessary replacement parts. Continued operability of the
affected valves will be verified as follows:
1) ECCS pumps and associated discharge check valves - Use of either
routine Quarterly Surveillance tests (which evaluate system flows and
idle pump status) or by the ability of the ECCS Keep-Fill systems to
maintain downstream pressure when the system is not operating.
2) SACS pump discharge check valves - Use of either routine Quarterly
Surveillance tests (which evaluate system flows and idle pump status) or
via verification of appropriate flow values during routine system
realignments.
3) FPCCU system pump discharge check valves - Verification of appropriate
flow values during routine system realignments.
4) FPCCU Filter-Demin Return to Torus valve - The safety function of this
valve is limited to withstanding seismic events. Therefore, there is no
functional safety significance associated with the subject failure mode.
5) FPCCU Filter-Demin Outlet Isolation check valve - The failure of this
valve does not constitute a Substantial Safety Hazard in that; a) the
failure mode of concern is readily detectable for the event upon which
this valve's safety function is based, and b) adequate compensatory
measures exist to mitigate the consequence of this valve's failure for
the event upon which its safety function is based.
If the above testing methodology identifies a new check valve failure,
the surveillance and/or verification frequency will be evaluated to
ensure continued operability. PSE&G will submit a written report within
30 days from the date of this notification. Should you have any
questions regarding this notification, please contact Mr. Dave Smith at
(609) 339-1282.
F. X. Thomson, Jr.
Manager - Licensing & Regulation
Page 4 of 4
INITIAL 10CFR21 NOTIFICATION
ANCHOR-DARLING CHECK VALVE HINGE ARMS
PUBLIC SERVICE ELECTRIC & GAS CO.
HOPE CREEK GENERATING STATION
DOCKET NO. 50-354
ATTACHMENT 1
LIST OF AFFECTED ANCHOR-DARLING CHECK VALVES
SAFETY-RELATED
SACS PUMP DISCHARGE CHECK VALVES (20", 150#)
1EGV-010
1EGV-013
1EGV-016
1EGV-019
CORE SPRAY PUMP DISCHARGE CHECK VALVES (12", 300#)
1BEV-013
1BEV-014
1BEV-015
1BEV-016
RHR PUMP DISCHARGE CHECK VALVES (18", 300#)
1BCV-002
1BCV-008
1BCV-099
1BCV-102
FPCC PUMP DISCHARGE CHECK VALVES (6", 150#)
1ECV-007
1ECV-040
FPCC FILTER DEMIN OUTLET CHECK VALVE (8", 150#)
1ECV-015
NON-Q SEISMIC
FPCC FILTER DEMIN OUTLET RETURN TO TORUS CHECK VALVE (6", 150#)
1EEV-007
ENCLOSURE 1 "FIGURE & PARTS LIST", 2 pages, omitted.
ENCLOSURE 2 "SWING CHECK (figures)", 1 page, omitted.
*** END OF DOCUMENT ***
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Page Last Reviewed/Updated Wednesday, March 24, 2021