ML20154P671
| ML20154P671 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 05/18/1988 |
| From: | Binoy Desai, Jape F, Whitener H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20154P667 | List: |
| References | |
| 50-324-88-16, 50-325-88-16, NUDOCS 8806060030 | |
| Download: ML20154P671 (10) | |
See also: IR 05000324/1988016
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UNITED STATES
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NUCLEAR HEGULATORY COMMISSION
ON
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REGION H
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101 MARIETTA STREET, N.W.
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ATLANTA. GEORGI A 30323
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Report Nos.: 50-325/88-16 and 50-324/88-16
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Licensee:
Carolina Power and Light Company
P. O. Box 1551
Raleigh, NC 27602
Docket Nos.: 50-325 and 50-324
License Nos.:
Facility Name:
Brunswick 1 and 2
Inspection Conducted:
March 24-30, 1988
Inspectors; M, /[ fl
6' - //- d
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H. L. Whitener
Date Signed
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B. B. Deriti
Date Signed
Approved by:
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F. Japef ;(ction Chief
Date Signed
Engineering Branch
Division of Reactor Safety
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SUMMARY
Scope:
This rountine, announced inspection was in the areas of witnessing the
Unit 2 primary containment integrated leak rate test (CILRT), review of the
CILRT procedure, evaluation of the CILRT results, and review of the as-found
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leak rate for the primary containment,
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Results:
No violations or deviations were identified.
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8806060030 880520
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ADOCK 05000324
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REPORT DETAILS
1.
Persons Contacted
Licensee Employees
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- M. S. Blinson, Senior ISI Specialist
C. R. Dietz, General Mana
- E. R. Eckstein, Manager, ger-Technical Support
- J. R. Holder, Outage Manager
M. T. Long, Engineering Technician
- R. M.'Poulk, Compliance Project Specialist
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Other persons contacted included leak rate test personnel.
Other Organizations
United Energy Services Corporation
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- R. Shirk, Leak Rate Test Engineer
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B. Black,
Leak Rate Test Specialist
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NRC Resident Inspector
- W. Ruland, Senior Resident Inspector
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- Attended exit interview
2.
Exit Interview
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The inspection scope and findings were summarized on March 30, 1988, with
those persons indicated in paragraph 1 above.
The inspectors described
the areas inspected and discussed in detail the inspection findings.
The
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inspector identified this test as a failed test.
With two failed-Type A
tests in succession, Unit 2 remaint on the accelerated Type A test
schedule.
No dissenting comments were received from the licensee.
The licensee did not identify as proprietary any of the materials provided
to or reviewed by the inspectors during this inspection.
3.
Licensee Action on Previous Enforcement Matters
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Thissubjectwasnotaddressedintheinspection.
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Unresolved Item
Unresolved items were not identified during this inspection.
5.
Containment Integrated Leak Rate Test - Unit 2 (70313, 70307)
The inspectors reviewed and witnessed test activities to determine that
the primary containment integrated leak rate test (CILRT) was performed in
accordance with the requirements of Appendix J to 10 CFR 50, ANSI-N45.4-
1972Property "ANSI code" (as page type) with input value "ANSI-N45.4-</br></br>1972" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process., test procedure PT-20.5, "Integrated Primary Containment Leak Rate
Test,,, the criteria of BN-TOP-1, Revision 1-1972, for a short duration
test, and ANSI /ANS 56.8 (exemption to Appendix J to allow Mass Point
analysis).
Selected sam31ing of the licensee's activities which were inspected
included:
(:.) review of test procedures to verify that the procedures
were properly approved and conformed with the regulatory requirements;
(2) observation of test performance to determine that test prerequisites
were completed, special equipment was installed, instrumentation was
calibrated and appropriate data were recorded; and (3) preliminary
evaluation of leakage rate test results to verify that leak rate limits
were met.
Pertinent aspects are discussed in the following paragraphs,
a.
General Observations
The inspectors witnessed and reviewed portions of'the test prepara-
tion, temperature stabilization, and data p'rocessing during the
period of March 24-30, 1988.
The inspectors observations included
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the following:
(1) The test was conducted in accordance with an approved procedure.
Procedure changes and test discrepancies were properly
documented in the procedure.
(2) Test prerequisites selected for review were found to be
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completed.
(3) Selected plant systems required to maintain test control were
found to be operational.
(4) Special test instrumentation was reviewed and found to be
installed and calibrated.
(5) Controls for preventing pressurized air sources inside
containment or externally pressurized penetrations were
established in the test procedure.
(6)
Instructions and documentation for venting, draining, and
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isolation of systems were established in the test procedure.
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(7) Problems encountered during the test were described in the test
event log.
(8) A containment temperature survey was performed to determine
representative locations of instruments..
(9) An in-situ check of CILRT instruments was performed prior to the
test.
(10) Selected procedure valve alignments reviewed against system
drawings to verify correct boundary alignment were adequate.
(11) Selected valve positions observed by the inspectors to verify
conformance to the procedure were adequate.
(12) Temperature, pressure, humidity, and flow data were recorded at
15-minute intervals.
Data were assembled and retained for final
evaluation and analysis by the licensee.
A final leak rate test
report will be submitted to the Office of Nuclear Reactor
Regulation pursuant to Paragraph V of Appendix J to 10 CFR 50.
b.
Procedure Review and Observations (70307) Units 1 and 2
Portions of PT 20.5, Revision 16, "Integrated Primary Containment
Leak Rate Test", dated March 15, 1988, were reviewed to verify that
test conditions, test controls, valve alignments and acceptance
criteria were specified.
The inspectors concluded that test
conditions and controls were specified in detail in the text; valve
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alignments and valve restoration were specified in detail in Table 2;
and system venting and draining was specified in Table 1.
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Permanent Revisions 15,16,17, and 18 to the test procedure were
reviewed.
These chan
(1) clarifying and improving
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test instructions, (2)ges related to:
implementing plant modifications and license
amendments, and (3) accommodating changes in associated support
procedures.
Tne inspectors concluded that these changes are within the
limitations of 10 CFR 50, Appendix J.
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A sample of valve alignments in the test procedure which establish
the test boundary were reviewed in detail against up to date plant
drawings to verify conformance with 10 CFR 50, Appendix, J.
The
valve alignments which were compared with plant drawings included the
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following plant systems:
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NSS System Isolation Valves
Page 42
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NSS System Boundary Valves
Page 43*
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Reactor Recirculation System
Page 44
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Isolation Valves
CAC System, Isolation
Page 45, 46
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Valves
CAC System Boundary Valves
Page 47, 48 *
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Containment Atmospheric
Page 49, 50*
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Monitoring System Isolation
Valves
RWCU System Isolation
Page 69
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Valves
RWCU System Boundary Valves
Page 69
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Instrument Air System Isolation
Page 70
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Valves
Instrument Air System Boundary
Page 70, 71, 72, 73*
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Valves
In the above table the page number refers to the pages in the
procedure where the system valve alignments are listed.
An asterisk
by the page numbers indicates verification of a portion of the valve
listing.
No valve misalignment!, were identified in this review.
In addition, the inspectors verified the position of selected valves
during a walkdown of the 52 ft. level of the drywell.
Based on the sample review, the inspectors concluded that valve
alignments conform to Appendix J requirements and the alignments were
adequately implemented,
c.
Containment Integrated Leak Rate Test (CILRT) Performance - Unit 2
(70313)
(1) Method
The integrated leak rate test was performed at the calculated
accident pressure (Pa) by the absolute test method. Acceptance
criteria were included in the test procedure for Mass Point,
Total Time and Short Duration testing in accordance with the
specifications of ANSI /ANS-56.8-1981, "Containment System
Leakage Testing Requirements"; ANSI-N45.4-1972, "Leakage-Rate
Testing of Containment Structures for Nuclear Reactors ; and,
BN-TOP-1, Revision 1-1972, "Testing Criteria for Integrated
Leakage Rate Testing of Primary Containment Structures for
Nuclear Power Plants ', respectively.
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The computer program for analysis of test data was provided by
United Energy Services Corporation.
The program included
capability for analysis of test data according to the Mass
Point, Total Time or Short Duration test methodologies.
The
test analysis was performed using the Mass Point Methodology.
The test duration was 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
The licensee had obtained an exemption to 10 CFR 50, Appendix J
to allow the use of the Mass Point methodology.
The exemption,
Amendment No.144 to License No. DPR-62, was effective as of
February 17, 1988.
(2)-Description
Values bounding the test conditions were as follows:
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Containment Volume
294981 cubic feet
Accident Pressure (Pa)
49 psig % per day
Maximum Allowable Leakage (La)
0.5 wt.
System conditions for performance of the integrated leak rate
test were as follows:
Reactor Vessel
Vented to containment atmosphere:
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water level at about 235 inches.
RHR System
One loop operating in the shutdown
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cooling mode.
Containment Ventilation
Fans tripped:
No forced air flow.
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System
Containment Isolation
Vented, drained, and aligned per
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System
procedure PT 20.5
After the structural inspection, the containment was pressurized
to 65 psia.
The following table gives a brief description of
test events extracted from the test log book.
Date
Time
Event
3/25
1920
Started pressurization of the primary
containment.
3/26
0443
Secured pressurization of containment at 50.5
psig.
0500
Stabilization period started.
0900
Four hour stabilization completed.
Type A test
initiated.
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Date
Time
Event
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(cont'd)
3/26
1140
Leakage survey teams identified packing ) leakage
on valves E 11-F021 (air), CAC-V17 (air and
821-F0328 (water).
Leak rate still under
evaluation:
no repairs made-at this time.
1330
AdjustedRHRcoolingflow.
1630
Increased RHR flow.
2245
RHR loop B put into shutdown cooling mode.
Vessel level dropped about 4 inches.
3/27
0745
Terminated Type A test for the following
reasons:
1.
Over the previous 15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> the leak
rate had tended to stabilize in the
range of 0.41 to 0.39 wt.% per day.
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Acceptance Ifmit is 0.375 wt.% per day.
2.
Reactor Vessel
water
level was
decreasing and approaching a LCO limit.
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Large
swings
in primary system
temperature appeared to be adversely
effecting the leakage rate since there
was no forced air flow.
1200
Reactor vessel water level raised to 235
inches, sumps pumped, RHR loop B returned to
ILRT line up, packing leaks on valves
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E11 F021A and CAC-V17 repaired.
Type A test
restarted.
2130
CAC neader was indicating 12 psig.
The
licensee decided to pressurize the header to
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quantify leakage through valve CAC-V4:
started pressurizing.
2335
started depres-
surizing.
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3/28
0145
CAC header depressurizad and left at 12
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psig.
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Date
Time
Event
(cont'd)
3/28
1200
Type A test terminated.
Leak rate is 0.307
wt.% per day and UCL is 0.312 wt.% per day.
These values meet the acceptance limit.
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1215
Supplemental test initiated.
Imposed leak
rate is 4.4 scfh, uncorrected.
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Supplemental test terminated. Lc= 0.687 wt.%
per day.
d.
Test Analysis and Results
(1) Type A Test
The Technical Specification for Brunswick Unit 2 specifies the
allowable containment leakage rate as 0.5 wt.% per day of the
containment volume of 294981 cu. ft. at the calculated accident
pressure (Pa) of 49 psig.
Therefore the acceptance limit for
the integrated leak rate (Type A) test (0.75 La) is 0.375 wt.%
per day.
Analysis of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of data, from 1200, 3/27 to 1200, 3/28,
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wt %g the Mass Point methodology yeilds a leak rate of 0.3066
per day.
The calculated leak rate at the upper 95%
confidence limit (UCL) is 0.3123 wt.% per day.
The UCL was
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calculated according to the method of ANSI /ANS 56.8.
Based on
this method the Ty
0.75 La (0.375 wt..ye A test is within the acceptance Ifmit of
. day).
The inspectors calculated weighted averages for containment
temperature, pressure
and vapor pressure using the weighting
factors and individual sensor data for a sample of data sets
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to verify agreement with the weighted averages and mass
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calculations generated by the ifcensee's computer program.
Subsequently, the mass points generated by the licensee's
program were used by the inspectors to calculate the leak rate,
and the 95% upper confidence leak rate.
The inspectors'
calculations agreed with the licensee's calculations.
(2) Supplemental Test
Appendix J requires that a supplemental test be performed to
verify the accuracy of the Type A test and the ability of the
CILRT instrumentation to measure a change in leak rate.
An
acceptable supplemental test method is described in Appendix C
of ANSI-N45.4-1972, as follows:
A known leak rate (Lo) is imposed on the containment and
the measured composite leak rate (Lc) must equal, within f
0.25 La, the sum of the measured Type A leak rate (Lam)
plus the known leak rate (Lo).
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The acceptance criteria is expressed as:
Lo + Lam - 0.25 La < Le < Lo + Lam + 0.25 La
A four hour supplemental test was performed by the imposed leak
rate method described in Ap?endix C to ANSI-N45.4-1972. - The
following values in units of wt.%/ day were obtained using Mass
Point analysis.
Mass Point (wt.%/ day)
Lam
0.3066
Lo
0.4905
0.25 La
0.125
Lc
0.6868
Using these values in the acceptance criteria yields the
following:
0.6721 5 0.6868 5 0.9221
Le = 0.6868 satisfies the above inequality and therefore,
the
supplemental test is acceptable.
The inspectors concluded that the "as left" containment leak rate
meets the Appendix J and Technical Specification 4.6. requirements.
6.
Status of Containment Leak Rate Testing
a.
Integrated Leak Rate Test - Unit 2
As discussed above, the licensee completed successful Type A and
supplemental tests starting at 1200 hours0.0139 days <br />0.333 hours <br />0.00198 weeks <br />4.566e-4 months <br /> March 27, 1988.
Prior to
this time a Type A test was run from 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br /> March 26, to 0845
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hours March 27.
During this test the licensee experienced problems
in maintaining the reactor water' temperature constant.
With no
forced air flow, the changing heat source affected the stabilization
of the containment atmosphere.
However, the Mass Point leak rate
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appeared to stabilize in the range of 0.39 to 0.4 wt.% per day over
the last 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> of the test.
When the test was terminated at 0745
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hours on March 27 the Mass Point leak rate was 0.395 and the UCL was
0.398 wt.% per day.
While these leak rates are less than the
Technical Specification allowable leakage of La (0.5 wt % per day),
they do exceed the Appendix J Type A acceptance leak rate of 0.75 La
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(0.375 wt.% per day).
Prior to rettarting the Type A test the
licensee pumped out the sumps, raised tita reactor vessel water level
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and repaired packing leakage on two valves, 511-F021A and CAC-V17.
Since leakage repair was made in order to meet the Appendix J 1eak
rate acceptance limit, the inspectors identified this test as a
failed integrated leak rate test at the exit interview.
Unit 2
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remains on an accelerated test schedule requiring a Type A test at
each refueling outage until two Type A tests in succession are
performed successfully.
This matter was discussed with licensee
management at the exit interview.
b.
ocal Leak Rate Tests Unit 2 (61720) (70313)
The inspectors reviewed preliminary results of the Type.B and C tests
to determine if leakage repairs would result in a failed "as-found"
leakage.
Although preliminary, the summations indicated no extremaly
large penetration leak rates were identified except the drywell head
seal and feedwater Penetrations SA and 98 which could not be
pressurized.
Visual examination of the drywell head seals showed the
outer seal was damaged while the inner seal appeared intact.
The
licensee concluded that no significant leakage from the drywell would
have occurred due to the inner seal.
Analysis of the cause of the
outer seal failure is still in progress.
In Penetration 9A only one
valve (inside check valve F010A) was leaking severely.
The outboard
valve (F032A) leak rate was only 4 scfh.
In penetration 98, both
isolation valves were leaking severely and could not be pressurized.
This would exceed a leak rate of La by the minimum path leak rate
analysis and results in an "as found" leak rate which exceeds the
allowable limits of 0.75 La.
The inspectors concluded that the "as
found" leakage condition of the containment represents a failed test
according )to the requirements of 10 CFR 50, Appendix J, Paragraph
III.A.5.(b , and III.A.6.(b).
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