United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9510060257

CP&L

Carolina Power & Light Company               William R. Robinson
PO Box 165                                   Vice President
New Hill NC 27562                            Harris Nuclear Plant

SEP 29 1995                                  SERIAL: HNP-95-087

United States Nuclear Regulatory Commission
ATTENTION: Document Control Desk
Washington, DC 20555

SHEARON HARRIS NUCLEAR POWER PLANT
DOCKET NO. 50-400/LICENSE NO. NPF-63
10 CFR 21 REPORT - CHARGING SAFETY INJECTION
PUMP MINIFLOW CHECK VALVE DEFICIENCY

Gentlemen:

On September 27, 1995, Carolina Power & Light Company (CP&L) determined
that deficiencies associated with Charging Safety Injection Pump (CSIP)
Miniflow Check Valves at the Harris Nuclear Plant were reportable under
10 CFR 21.  CP&L hereby submits the enclosed report describing a
deficiency in Anchor Darling supplied 2" check globe valves which
resulted in not meeting forward flow requirements through the CSIP
miniflow lines and also resulted in excessive valve backseat leakage.
Harris is Nuclear Plant LER 95-008 dated September 28, 1995, describes an
event where the "B" CSIP was placed in service when it was inoperable
because of the inability of it's miniflow check valve to meet forward
flow testing requirements.  Due to plant conditions at the time (Mode 4)
this failure of the check valve did not create a substantial safety
hazard.  However, the forward flow deficiency could have created a
substantial safety hazard under different plant conditions and may also
be applicable to other nuclear plants.

Questions regarding this submittal may be referred to Mr. T. D. Walt at
(919) 362-2711.

                                        Sincerely,

MGW

Enclosure

c:   Mr.  S. D. Ebneter
     Mr.  S. A. Elrod
     Mr.  N. B. Le
     Mr.  F. Bensinger (Anchor Darling Valve)

     State Road 1134 New Hill NC  Tel 919 362-2502  Fax 919 362-2095

                                                  ENCLOSURE TO HNP-95-087

                     CAROLINA POWER & LIGHT COMPANY
                          HARRIS NUCLEAR PLANT

                  FAILURE OF CHARGING SAFETY INJECTION
                       PUMP MINIFLOW CHECK VALVES

                           SEPTEMBER 29, 1995

                       REPORTABLE UNDER 10 CFR 21

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                                                  ENCLOSURE TO HNP-95-087

SUBJECT:

Harris Nuclear Plant, 10 CFR 21 reportable deficiency.  Failure of
Charging Safety Injection Pump (CSIP) Miniflow Check Valves.

ITEM WHICH FAILS
TO COMPLY:

2" - 1878 Socket Ends Stainless Steel Piston Check Globe Valve
(HNP Valve Nos. 1CS-179 & 1CS-193)

SUPPLIED BY:

Anchor Darling Valve Company, Williamsport, Pa. 17701.

NATURE OF
DEFICIENCY:

Check valves 1CS-179 and 1CS-193 are in the miniflow lines for the CSIPs
Trains A & B respectively.  The original valves installed utilized a
bonnet-to-body seal weld.  During Refueling Outage No. 5 (May 1994) a
design change was implemented to replace the original valves with the
subject valves which utilize a pressure seal bonnet closure design.  This
modification was completed to improve accessibility to the valve's
internals for ASME Section XI inspection purposes.  There were no
recorded occurrences of forward flow or backseat failures with the
original valves.

The design function of these check valves is twofold.  First, the valve
is designed to provide forward flow through the miniflow line during
normal and accident conditions.  Miniflow ensures that there is at least
60 GPM through a CSIP even if the pump becomes dead-headed due to high
Reactor Coolant System (RCS) pressure conditions.  Therefore, these check
valves must be capable of passing adequate forward flow to allow the
miniflow line to accomplish its safety function.

Second, the valve is designed to prevent backflow through the miniflow
line to prevent flow diversion from an operating CSIP in the event one of
the other CSIPs failed or was not in service.  Flow diversion might
prevent sufficient flow to the RCS and thereby prevent the CSIP from
meeting its safety function.  Thus, these check valves must be capable of
preventing backflow to accomplish their safety function.

These valves have exhibited deficiencies since October 7, 1994.  The
following is a short description of these deficiencies:

     On October 7, 1994, Valve 1CS-179 exhibited back leakage (value not
     recorded) and the valve piston was replaced.

                                  E1-2

                                                  ENCLOSURE TO HNP-95-087

NATURE OF
DEFICIENCY: (continued)

     On January 13, 1995, Valve 1CS-179 was tested and exhibited 6 GPM
     back leakage.

     On January 13, 1995, Valve 1CS-193 was tested and exhibited 3 GPM
     back leakage.  Corrective maintenance found the resilient seat only
     two thirds the way around the disc.

     On July 8, 1995, 1CS-193 failed a backseat test due to the valve
     being stuck open.  The disc assembly which consisted of a disc, disc
     skirt, retaining ring, and resilient (soft) seat was replaced with a
     single piece disc assembly (without a soft seat) supplied by Anchor
     Darling.

     On August 4, 1995, 1CS-193 failed a forward flow test.

The cause of these failures appear to be the cocking of the piston
towards the valve outlet port.  The cocking was apparently caused by the
relatively large hydraulic surge which occurs when the CSIP is started.

These valves were installed in May 1994.  They were ordered using a
specification which included the following technical requirements:

4.1.3     "All materials except packing,..., shall be suitable for a
          minimum  of 40 years service."

4.3.2     "The valve design shall be based on the following pressure and
          temperature.  The valve must maintain pressure integrity and
          operability at these conditions.  The valves shall also be
          capable of operation with the specified differential pressure
          across the valve disc.

          Design Pressure:         2735 psig for stainless valves.

          Design Temperature:      650 degrees F metal-to-metal seat
                                   design on piston check.

          Differential Pressure:   2735 psig for stainless steel valves."

5.8       "The valve parts shall be compatible with the specified
          environment and shall be of suitable material to withstand the
          operating conditions specified herein."

7.4.2     "Following the shell hydrostatic test, seat leakage testing
          shall be performed in accordance with MSS-SP-61, except the
          hold time shall be 5 minutes minimum.  Allowable leakage is 2
          cc/hr. per inch of nominal valve size."

There are two additional safety-related valves of this type installed in
the plant at this time:

          1CS-536 Boric Acid Transfer Pump A Discharge Check Valve
          1CS-546 Boric Acid Transfer Pump B Discharge Check Valve

                                  E1-3

                                                  ENCLOSURE TO HNP-95-087

NATURE OF
DEFICIENCY: (continued)

These two valves operate at approximately 120 psi, while the CSIP check
valves operate at 2712 psi.  Therefore this application is at
significantly lower pressure than the CSIP miniflow application and are
not subject to the large hydraulic forces caused by pump start-up.  These
valves were installed on February 4, 1994 and have undergone surveillance
testing with no occurrence of forward flow or backseat failures.  The
defect in question is not considered applicable to these valves.

SAFETY IMPLICATIONS:


The substantial safety hazard that could have been created is the failure
of these valves to pass sufficient forward flow to protect the CSIP when
alternate miniflow is required and to prevent backflow through the
miniflow line to prevent flow diversion from an operating CSIP in the
event one of the other CSIPs failed or was not in service.

DATE PROBLEM
WAS CONFIRMED:

The need to evaluate this deviation was identified on August 17, 1995.
It was evaluated and determined to be reportable on September 27, 1995.

PROBLEM REPORTED:

On September 29, 1995, the NRC Operations Center was notified of this
reportable item under 10 CFR 21.

CORRECTIVE ACTION:

The valves that experienced failures (1CS-179 and 1CS-193) were replaced
by valves of the same design as originally installed.  The modification
which replaced these valves and the acceptance testing demonstrating full
flow was completed on September 25, 1995.  The original check valve
design is still in use on the third CSIP (C Train).  No recorded forward
flow or backseat failures have occurred on this valve.  No further
corrective action is planned.

                                  E1-4

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