ML20128K382
| ML20128K382 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 06/18/1985 |
| From: | Elsasser T, Ferlic K, Holden C, Robertson J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20128K349 | List: |
| References | |
| 50-309-85-09, 50-309-85-9, NUDOCS 8507240118 | |
| Download: ML20128K382 (10) | |
See also: IR 05000309/1985009
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U. S. NUCLEAR REGULATORY COMMISSION
REGION I
Docket / Report:
50-309/85-09
License: DPR-36
Licensee:
Maine Yankee Atomic Power Company
Inspection At:
Wiscasset, Maine
Dates:
April 14 to May 25, 1985
Inspe'ctors:
-/ L eth P P b h
4 /1/M-
- C. Holden, Senior Resident Inspector
date
%1h t fk&
&In/K
K. Ferlic, Project Engineer
date
t ..-. . m g -t_ %_
6/sv/&f
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gon ,'
tor Engineer
date
'A- M~
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Approved:
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T. C. Elsa
Chief, Reactor Projects Section 3C
'date~
Summary:
Inspection Report 50-309/85-09
Areas Inspected: Routine resident inspection (147 hours0.0017 days <br />0.0408 hours <br />2.430556e-4 weeks <br />5.59335e-5 months <br />) of the control room, ac-
cessible parts of plant structures, plant operations, radiation protection, physi-
cal security, fire protection, plant operating records, maintenance, surveillance,
radioactive effluent sampling program, open items, and reports to the NRC.
No
violations were found.
Results: Two administrative problems'were noted concerning containment integrity.
One was a licensee identified violation and the other involved the' failure to ad-
ministratively control vent and drain valves for containment coolers.
Operator
knowledge of some system interfaces during maintenance was lacking.
Improvements
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in the shift turnover practices appear to provide better continuity between shifts.
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8507240118 850619
ADOCK 05000309'
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DETAILS
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Persons Contacted
Within this report period, interviews and discussions were conducted with
various licensee personnel, including reactor operators, maintenance and
surveillance technicians and the licensee's management staff.
2.
Summary of Facility Activities
Details of the following are included in the body of the report.
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On April 14, 1985, 120 volt AC bus 3 was lost due to a failure of the. con-
nector at the outlet of the inverter. The bus was cross connected with vital
bus 2 while the connector was replaced. Vital bus 3 was returned to the in-
verter power supply on April 17.
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On April 24, 1985 at 2:04 p.m., Maine Yankee Nuclear Power surpassed a life-
time production goal of 60 billion kilowatt-hours.
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The plant operated.at 100 percent power from the beginning of the inspection
period until April 30, 1985, when a load reduction was initiated to replace
the main generator exciter fuses.
A plant trip occurred while returning the
plant to full power later that same day. The" trip was caused by a technician
who inadvertently grounded contacts in the low suction pressure trip circuit
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of the turbine driven feed pump while conducting maintenance. Tne reactor
was returned to full power on May 1.
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On May-4, 1985, the licensee reduced power and shutdown the plant for main-
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tenance.
Replacement of the diodes for the main generator exciter was the
major maintenance item accomplished. The reactor was taken critical on May
6 and returned to full power on May 8 following delays for chloride cleanup
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of the steam generators.
On May 10, 1985, plant power was reduced to place the electric driven feed
-pumps in service. Plant power was returned to 97 percent (the maximum power
l'evel with electric driven feed pumps) for_the remainder of the inspection
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period in order to perform maintenance on the steam driven feed pump.
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3.
Licensee Action on Previous Inspection Findings
.(Update) Followup. item'(IFIL309/85-06-02) Spacing between new fuel rack tubes.
The licensee determined that the spacing needed between each of the spent fuel
rack tubes to provide the necessary flux trap for 3.3 weight percent fuel was
.692. inches'of water.-
In' order to achieve this spacir,g on the new phase two -
racks, holes were drilled in each face of the tubes to remove the air between
the.boral and the; tube face. The inspector.will continue to. follow this item.
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4.
Review of Plant Operations
The inspector reviewed plant operation through direct observation throughout
the reporting period.
Except as noted, conditions were found to be in com-
pliance with the following licensee documents:
-- Maine Yankee Technical Specifications
--- Maine Yankee Technical Data Book
Maine Yankee Fire Protecticn Program
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Maine Yankee Radiation Protection Program
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-- Maine Yankee Tagging Rules
Administrative and Operating Procedures
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' a.
Instrumentation
Control room process instruments were observed for correlation betveen
channels and for conformance with Technical Specification requirements.
No unacceptable conditions in process instrumentation were identified.
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b.
Annunciator Alarms
The inspector observed various alarm conditions which had been received
and acknowledged. These conditions were discussed with shift personnel
who were knowledgeable of the alarms and actions required. Operator re-
sponse was verified to be in accordance with procedure 2-100-1, Response
,to Panalarms, Revision 5.
During plant inspections, the inspector observed the condition of equip-
ment associated with various alarms.
No unacceptable conditions were
identified.
c.
Shift Manning
The operating shifts were observed to be staffed to meet the operating
requirements of Technical Specifications, Section 5, both to the number
and type of licenses. Control room and shift manning were observed to
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be in conformance with 10 CFR 50.54.
d.
Radiation Protection Controls
Radiation Protection control areas were inspected. -Radiation Work Per-
mits in use were reviewed, and compliance with.those documents, as to
' protective clothing and required monitoring instruments, was inspected.
Proper posting and control of radiation and iiigh' radiation areas was re-
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viewed in addition to verifying requirements for wearing appropriate
personnel monitoring devices.
There were no unacceptable conditions
identified.
The licensee has initiated a program to upgrade the storage and cleanli-
ness of the plant. Each department contributed to the workforce used to
identify, sort, store and dispose of plant equipment that had accumulated.
Various crews were assigned to specific areas of the plant for cleaning
and decontamination. The result has been a reduction in the radiation
levels at a number of locations throughout the plant.
e.
Plant Housekeeping Controls
Storage of material and components was observed with respect to preven-
tion of fire and safety hazards.
Plant housekeeping was evaluated with
respect to controlling the spread of surface and airborne contamination.
The inspector conducted a tour of the containment building and noted a
number of articles that had the potential of obstructing recirculation
flow from the containment sump.
These finding were discussed with plant
management. Subsequently, the licensee removed the potential obstructions
and conducted a cleanup of the area. The inspector had no further com-
ments,
f.
Fire Protection / Prevention
The inspector examined the condition of selected pieces of fire fighting
equipment. Combustible materials were being controlled and were not found
near vital areas. Selected cable penetrations were examined and fire
barriers were found intact. Cable trays were clear of debris. No abnormal
conditions were identified.
g.
Control of Equipment
During plant inspections, selected equipment under safety tag control
was examined.
Equipment conditions were consistent with information in
plant control logs.
h.
Plant Operations Review Committee (PORC)
The inspector attended Plant Operations Review Committee (PORC) meeting
on April 25, 1985. Technical specification 5.5 requirements for required
member attendance were verified. The meeting agenda included procedural
changes, proposed changes to the Technical Specifications and field
changes to design change packages. The meeting was characterized by frank
discussions and questioning of the proposed changes. In particular, con-
sideration was given to assure clarity and consistency among procedures.
Items for which adequate review time was not available were postponed
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to allow committee members time to review and comment. Dissenting
-opinions were encouraged. The inspector had no further comments.
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1.
Control' Room Atmosphere
During this report period, in addition to the normal review of the con-
trol' room, the inspector reviewed the manner in which the operators car-
ried out their daily duties. Recent changes to the Maine. Yankee Dress
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. Code have set.new standards for operator appearance which has contributed
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to the professional atmosphere of the control room.
Additionally, the
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licensee has' instituted a formal review period prior:to actual shift
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turnover.to enhance the information flow between shifts. Each oncoming
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Plant Shift Supervisor and Shift Operating Supervisor reviews plant con-
ditions and'then conducts-a brief of the oncoming crew. These briefings
review plant problems and anticipated evolutions for the shif t.~ Each
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member of the. oncoming shift then conducts an on station turnover with~
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the off going-crew.
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Loss of'120 Volt Vital Bus 3
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On April 14, 1985,- while at 100 percent power, the main control board
annunciator for channel C Reactor Protective System (RPS) alarmed due
to power being _ lost from the 120 volt AC vital bus 3. _ Bus 3 was cross-
tied to vital bus 2. Further investigation into the. failure indicated
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that the cable connector at the outlet of the inverter had overheated
and failed causing loss.of the bus.
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The licensee obtained spare parts and repaired the connector. Vital bus
3 was returned to service on April 16. The' inspector had no further
questions.
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Steam Driven Feed Pump
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.On May 10, 1985, an increase in the vibration reading _ for the Steam
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Driven feed pump (P-2C)Jwas noticed..The pump ~was removed from. service
and the two electric driven feed pumps were'placed_in service. Investi-
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gation into the causelof-the high vibration in P-2C revealed a piece of
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a stud and nut had entered the' impeller area and were the source'of the
vibration. The impeller'and~ pump shaft were. replaced and the pump was
balanced.
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'The-licensee conducted a search for the source of the stud..One'of'the
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. heater drain pumps was inspected since the stages of these multistage
pumps are bolted together. While inspecting the "B" heater' drain pump _
the remainder offthe stud;was-found. All interstage fasteners were:re-
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. torqued and the pump was returned to. service. The "A" heater drain pump
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was ramoved from. service and checked but~no deficiencies were noted.
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No violations.were. identified.
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1.
! Troubleshooting Loop 1 Temperature Detector
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On May 22, 1985,._the plant conducted a routine entry into containment.
.One of the maintenance items conducted during this entry was the
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troubleshooting of Loop-1. Resistance Temperature Detector (RTD) for the
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cold leg temperature (T cold). The plant had noticed a difference between
the three T cold Loop instruments and was investigating the problem. The
maintenance involved pulling the penetration cable connector inside con-
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tainment and measuring the resistance from the connector to the RTD. The
inspector observed the maintenance activities inside containment and the
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quality control coverage that was provided.
No problems were' identified.
-The-inspector: returned to the control room after exiting containment and
observed the precautions the control ~ room had taken prior to removal of
'the penetration. connector. All. bypass keys were installed in the Reactor
. Protective System (RPS) for channel. A. Train 8 of the Auxiliary Feedwater
Start circuit (AFWS) was also in test. When questioned, the operators
were unsure of the exact interaction of the AFWS with the' loop 1~RTD work
but knew that both precautions were required to support the RTD trouble-
- shooting.
Further investigation' revealed that a steam generator level
instrument was also included in the connector that was being pulled to
check loop 1 RTD. This level instrument fed the train B of the AFWS.
Inoperability of this level instrument necessitated placing train B in
test. The inspector reviewed the Technical Specification. requirements
for ' operability of these instruments.
No violations were noted.
The inspector expressed the concern to plant management that the opera-
tors need detailed knowledge of the plant instrumentation that is affected
during maintenance.
In this case,'the operators _were aware that.the AFWS
system would be affected because th'e I&C'section had-briefed them prior
to beginning the maintenance. f Additionally, these limitations were ad-
dressed on the repair order.
Because these controls'were in place,.the
operators were aware that some of the capabilities of-the AFWS would be
. temporarily lost.
However, as explained above, when questioned as to
the exact nature-of the system interaction, the operators were not sure
of the' status of-this system.
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The inspector had no further comments,
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Component Cooling Valves'in Containment
' On'May 8,_1985, the licensee identified 52 vent anc drain ' valves in the
~ Primary Component Cooling (PCC) system that were not on the control ~
drawings. As a result, these valves were'not being administrative 1y con-
trolled.by the procedure covering containment integrity. The valves are
'on the portions of the PCC system that services _the reactor containment
- air. recirculation ecoler, containment penetration coolers and the return -
lline from the' Control Element Assembly-(CEA)' drive mechanism air cooler._
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All but one of the valves are located inside containment. The purpose
of these valves is to assist in the draining or venting of the contain-
ment coolers.
Each of the subject valves was verified in the closed position. There
were no indications that these valves had been opened based upon the
leakage rate of PCC and the lack of any indications of leakage around
the coolers.
The licensee conducted an inspection of the various coolers inside of
containment in order to identify any other valves which were not on the
plant controlica drawings. The valves in question were labeled, lock
wired closeri and placed on the containment integrity valve list.
The inspector had no further comments,
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Maintenance Outage
The plant conducted a maintenance outage from May 4 to May 6. Two of the
nine diodes for the main generator had failed routine surveillance checks.
Based on discussions with the manufacturer, the licensee decided to re-
place all nine diodes. A variety of additional maintenance items were
accomplished during the outage,
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Plant Trip
On April 30, 1985, during maintenance on the steam driven feed pump (P-
2C) low suction pressure trip delay circuit, the plant tripped from ap-
proximately 95 percent power. All systems functioned normally. Investi-
gation revealed that the technician performing the maintenance had
grounded a pair of contacts in the low suction pressure circuit and
caused pump P-2C to trip. The turbine trips automatically on a loss of
pump P-2C and the reactor tripped due to loss of the turbine. The reactor
was taken critical at 5:45 a.m. on May 1 and returned to 100 percent
power.
5.
Observations of Physical Security
The resident inspector made observations, witnessed and/or verified, during
regular and backshift hours, that selected aspects of the sec.arity plan were
in accordance with the regulatory requirements, physical security plan and
approved procedures as noted below:
Maine Yankee Plan, dated October 1979
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15-1, Security Procedures, Revisinn 11
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15-12 Emergency Contingency Procedures, Revision 1
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Observations and personnel interviews indicated that there was sufficient
staffing of all three shifts. Selected barriers in the protected area, access
control area, and the vital area were observed and random monitoring of the
isolation zone was performed.
Observations of vehicle searches were made.
Observations of badging, escorting and communications were made. The inspector
held discussions with plant management concerning the method of providing
access control to portions of the protected area during maintenance.
No deficiencies were identified.
6.
Plant Maintenance
The inspector observed and reviewed maintenance and problem investigation
activities to verify compliance with regulations, administrative and mainten-
ance procedures, codes 7. d standards, proper QA/QC involvement, safety tag
use, equipment alignment, jumper use, personnel qualifications, radiological
controls for worker protection, fire protection, retest requirements, and re-
portability per Technical Specifications.
The following activities were in-
cluded: Troubleshooting of the Loop 1 RTD instrument and weld repair of the
Emergency Diesel generator air filter supports.
No deficiencies were identified.
7.
Surveillance Testing
The inspector observed parts of tests to assess performance in accordance with
approved precedures and LC0's, test results, removal and restoration of
equipment, and deficiency review and resolution. The timed stroke testing of
safeguards valves was reviewed. Test results indicated that LM-A-57, the
automatic isolation valve for a variety of containment pressure instruments,
failed to meet the acceptance criteria. Analysis indicated the valve operated
correctly but the indication in the control room was incorrect. A discrepancy
report was issued to initiate corrective action. Adjustments to the valve
limit switch corrected the indication problem. The inspr-tor had no further
questions.
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8.
R
a Licensee Identified Violation
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On up..
24, 1985, the air regulator filter on BD-T-22 was to be replaced.
BD-T-22 is the containment isolation valve in the blowdown line from Steam
Generator No 2. In order to replace the regulator filter, the valve was to
be shut and the air to the regulator secured. This process was to take ap-
proximately thirty minutes.
At 10:00 a.m. BD-T-22 was shut and deactivated
by securing the air to the regulator. During reassembly of the regulator a
problem was encountered and BD-T-22 was not reactivated until 3:11 p.m., ap-
proximately 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> later. Technical Specification 3.11 states within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />
an inoperable containment isolation valve must be returned to service or the
affected pentration isolated by use of at least one manual, renotely operated
or deactivated automatia isolation valve secured /. tagged) in the closed posi-
tion or by use of a blind flange. The penetration was isolated by shutting
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BD-T-22, the deactivated automatic isolation valve, but it was not tagged.
This event was reported to the NRC inspector on site and is a license identi-
fied violation which meets the criteria of NRC policy for not issuing a vio-
lation.
Inspector review of the circumstances indicated the valve, BD-T-22, was not
tagged when deactivated because it had not been identified as a containment
isolation valve with Technical Specification limitations on the discrepancy
report (No.1426) issued to replace the air regulator filter.
This oversite
appeared to be due, in part, to the issuance of an earlier discrepancy report
(No 1401) for inspection of the air supply filters on 450 air operated safety
and non-safety related valves. On this earlier discrepancy report (No. 1401),
the 450 valves were identified generically as containing Technical Specifica-
tion valves. Individual safety related valves were not identified. The Shift
Operating Supervisor or Plant Shift Supervisor was left with the responsibil-
ity for determining the classification (safety /non-safety) for each of the
valves. A priority for changing the air filters was established based on the
valves ability to degrade a safety function or interrupt plant operations if
the filters clogged.
The licensee indicated that the violation was caused by the failure of opera-
tions personnel to properly identify the tagging requirements for the valve.
Management also felt the issuance of the discrepancy report with 450 safety
and non-safety valves contributed, if not, caused the error.
Corrective ac-
tion completed by the licensee include: (1) the immediate separation of the
safety related filters from the non-safety related filters on the discrepancy
report, (2) review of the overall process for handling similar problems to
ensure a generic program or procedural inadequacies do not exit, and (3) re-
view of the event by plant operators.
The inspector had no further questions.
9.
Review of Low Pressure System Interfaces
In response to recent industry problems with the isolation systems between
low pressure safety injection systems and high pressure safety injection sys-
tems, the resident inspector conducted a review of the licensee's surveillance
and maintenance programs covering those valves which isolate primary coolant
from low pressure Emergency Core Cooling System (ECCS) piping and components.
If low pressure ECCS piping outside of containment is overpressurized and then
ruptures, the cooling water it supplies will not be available for recircula-
tion during an accident.
Maine Yankee had received a Confirmatory Order from the NRC on April 23, 1981,
which required the installation of additional check valves in the low pressure
safety injection system to protect it against overpressurization. The inspec-
tor verified the as-built isolation interfaces between high and low pressure
piping, reviewed and evaluated the isolation valve surveillance and mainten-
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ance procedures, verified the proper application of procedures and reviewed
plant specific and industry wide experience to ensure the lessons learned were
incorporated into the licensee's program.
The interfacing systems reviewed included the High Pressure Safety Injection
system (HPSI), the Low Pressure Safety Injection system (LPSI) ,.the Residual
Heat Removal (RHR) system, and the Safety Injection Tanks (SIT). The two sys-
tems that had an interface which could result in an overpressurization of low
pressure systems was the interface between the HPSI and LPSI systems. Prior
to cycle 7 operations, Maine Yankee installed an additional check valve in
the LPSI piping and the capacity to conduct surveillance tests of these check
valves. During an accident condition, this check valve is the only barrier
between the high pressure and the low pressure systems.
The discharge of the LPSI pumps is via piping designed to withstand.600 pounds
of pressure. The HPSI system is designed to withstand full accident pressure
of 2485 pounds. These two systems combine before entering containment. A check
valve protects the low pressure system from the high pressure system. During
normal operation a motor operated valve in each of the high pressure and low
pressure piping provides an additional barrier between the two systems.
The inspector reviewed the licensee's surveillance testing of these systems.
In addition to the routine time testing of the motor operated ECCS valves,
T' i licensee monitors the pressure in the piping between the check valve and
..ie motor operated valve in the LPSI system to detect any leakage past the
check valve. The In Service Testing program conducts leak checks and flow
checks of these systems during refueling outages. The inspector reviewed the
test results and the maintenance history of these pressure barrier components.
During the refueling in June,1975, leakage of these barriers (check valves
and motor operated valves) was detected and corrected.
The inspector had no further questions in this area.
10.
Exit Interview
Meetings were periodically held with senior facility management to discuss
the inspection scope and findings.
A summary of findings was presented to
-the licensee at the end of the inspection.
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