IR 05000312/1987023
| ML20235X012 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 09/30/1987 |
| From: | Clark C, Richards S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML20235X010 | List: |
| References | |
| 50-312-87-23, IEIN-85-071, IEIN-85-71, NUDOCS 8710190163 | |
| Download: ML20235X012 (9) | |
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U. S. NUCLEAR REGULATORY COMMISSION
REGION V
Report No.
50-312/87-23 Docket No.
50-312 License No.
DPR-54 Licensee:
Sacremento Municipal Utility District P. O. Box 15830 Sacramento, California 95813 Facility Name: Rancho Seco Nuclear Generating Station Inspection at: Clay Station and Sacramento, California Inspection Conducted: July 14 - September 11, 1987 Inspector:
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C. park,' Reacto Inspector
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ate Signed Approved by: [
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5. Ri s, Crff'ef
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Date Signed
En ring Section
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Inspection During the Period of July 14 - September 11, 1987 (Report No.
50-312/87-23)
Areas Inspected: Routine announced inspection of activities relating to a Containment Integrated Leak Rate Test (ILRT) and an IE Information Notice.
An initial inspection was performed the week of July 14-17, 1987, to support a July 17, 1987, scheduled ILRT date, which was delayed until August 28, 1987. The second inspection was performed at the facility during the period of August 24 - September 4, 1987. The inspection included review of procedures and records, interviews with personnel, witnessing portions of the ILRT, inspection of the containment building, associated penetrations and piping systems. During this inspection, inspection procedures 70307, 70313 l
and 92701 were covered.
Results:
In the areas inspected, no violations of NRC requirements were identified.
8710190163 871001 DR ADOCK 05000312 PDR
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l DETAILS
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Persons Contacted a.
Licensee
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- J. McColligan, Director Plant Support
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- *S. Redeker, Assistant'to Nuclear Operations Manager
- R. Dieterich, Nuclear. Licensing
'*J. Robertson, Nuclear Licensing
- G. Paptzum, ILRT. Test Director A. Clary, ILRT Lead W. McMahon, ILRT Lead D. Brown, Quality Engineer b.
Contractor Personnel
-(1) Bechtel-
'K. Pimentel, ILRT Engineer (2) Volumetrics P.'Zephier, Engineer R. Elder, Engineer
- Denotes those personnel in attendance at the exit meeting on September 4, 1987.
The inspector also held discussions with other licensee and contractor personnel involved with the ILRT.
'2.
Containment Integrated Leak Rate Test (ILRT)
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Procedure Review The inspector reviewed the Unit 1 ILRT procedures as described in the licensee's surveillance procedure SP.605, Revision 2 of August 3, 1987 (and latest applicable temporary change notices)
entitled " Variable Interval Reactor Building Integrated Leakage Rate Test." This review was to ascertain compliance with plant Technical Specifications, regulatory requirements, and applicable industrial standards as stated in the following documents:
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Technical Specifications for the Rancho Seco Unit 1, Section l
4.4.1.
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Appendix J to 10 CFR 50, " Primary Reactor Containment Leakage Testing for Water Cooled Power Reactors."
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American National Standard, " Leakage-Rate Testing of
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Containment Structures for Nuclear Reactors," ANSI N45.4-1972.
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Topical Report BN-TOP-1, Revision 1, " Testing Criteria for Integrated Leakage Rate Testing of Primary Containment Structures for Nuclear Power Plants," Bechtel Corporation.
American National Standard. " Containment System Leakage Testing Requirements," ANSI /ANS-56.8-1981.
Based on the procedure review, review of records and observation of work activities, comments and procedure improvement recommendations are provided in Section 2.d. of this report.
No violations or deviations were identified, b.
Review of Records The inspector' reviewed calibration records for the instrumentation used in the ILRT.
That is, the eighteen Resistance Temperature Detectors (RTDs), six dew cells, two pressure gauges used to measure containment air mass, and the flow element used to measure the induced leak during the verification portion of the ILRT.
All instruments had been calibrated within the last six months with NBS traceability certificates available.
The inspector also discussed the in situ check of the instrumentation with the licensee.
The inspector reviewed the records to assure that the following required activities were performed prior to initial pressurization:
(1) Completica of all available identified local leakage rate testing and identification of leak rates prior to and efter any repairs.
(2) Removal or venting of items listed on the equipment protection and venting schedule.
(3) Inspection of interior and exterior containment surfaces and components for evidence of deterioration or damage.
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(4) Containment sump water levels below high level mark.
(5) ILRT measurement system properly installed and functionally
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checked.
(6) Pressurization system tested; including proper operation of the air compressors, after-coolers, moisture separators, air dryers, valves and blowdown muf fler/ silencer.
(7) Containment ventilation system adjustments completed.
(8) Valve lineups completed.
See Section 2.d. of this report for comments in this area.
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(9) Pressurization system in service.
(10) Cont'ainment temperature survey to' verify temperature sensor l
locations.
The survey was performed prior to the ILRT, without J
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fans running,'and again after the ILRT with normal containment
ventilation fans running.
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.No violations or deviations were' identified.
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Observation of Work and Work Activities Prior to the ILRT,.the regional inspector performed area surveys for pressurized components'(such as tanks, fire extinguishers, etc.),
valve lineups and. instrument location assignments within the Containment Building.. The purpose of the' instrument survey was'to locate and evaluate the placement of the temperature sensors and
' dewpoint ~ sensors.
This inspection revealed that the sensors were located within the tolerances of the installation procedures.
The operation'of the pressurization equipment (air compressors, after-coolers and ' air dryers) used for pressurization of the Containment Building was inspected to assure that procedures for prevention of potential problems were enforced.
This included evidence of ' checking the pressurizing air for indications of oil
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contamination,' establishment of communications between ILR1 control center and the pressurization station, adequate supply of' cooling water to the after-coolers, and that control of the after-cooler air temperature was being maintained during pressurization.
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The inspector witnessed selected portions of the following ILRT activities:
(1) Initial pressurization to 52 (+1,-0) psig.
(2) Stabilization.
(3) Data Acquisition.
(4) Completion of ILRT.
(5) Leakage Rate Verification Test.
(6) Containment Building Depressurization.
Applicable electrical and mechanical penetrations were inspected.
Applicable portions of the valve lineups were inspected to see that they were completed in accordance with procedure and that no unidentified artificial barriers were erected.
During the initial valve line-ups, the inspector identified some concerns and procedure improvements comments that are discussed in Section 2.d. of this report.
The overall performance of the ILRT crew members was observed by the
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inspector.
Attributes evaluated were:
availability of test j
procedures; test prerequisites being met; proper plant systems in
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k service; special test equipment calibrated and in service; and crew actions timely and correct.
Crew members had received ILRT training n
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L of their duties.
The licensee commenced pressurizing the containment at 4:30'a.m. on August 30, 1987.
Pressurization was. secured f rom 6:30 to 7:30 a.m.,
while the licensee investigated a' fire alarm that was generated from inside the containment.
Bechtel informed the licensee that some fire alarm sensors are pressure sensitive around 3-5 psig
. containment pressure.
Since all inside containment RTO's indicated temperatures less than 90 degrees Fahrenheit and no other evidence of a fire inside the containment could be identified, pressurization was continued at 7:30 a.m.
Test pressure (52 +1.0 -0.0 psig) was reached and the initial four hour (minimum) hold / stabilization period was initiated at approximately 6:30 a.m. on August 31, 1987.
As a result of ILRT data scatter, the initial stabilization period was extended to 4:30 p.m. on August 31, 1987, at which time the
' licensee /Bechtel commenced taking official ILRT data.
At 2:30 p.m.
on September 1, 1987, the licensee announced that due to unacceptable data scatter (attributed to DEW cell readings) the normal containment ventilation system fans and cooling water were
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being turned on to provide a better mixture of containment air mass.
The licensee stated that it appeared the initial containment air mass had not reached stabilization when initial ILRT data' collection was started at 4:30 p.m. on August 31, 1987.
To obtain a better picture of the actual containment dewpoint temperature (water vapor pressure), the licensee elected to circulate the upper containment air mass above the sixty-six foot elevation (where only one dew cell was installed) through the containment areas below the sixty-six foot elevation (where six dew cells were installed).
After running the normal containment ventilation system fans for thirteen hours, the licensee declared a restart of the ILRT data collection at 3:00 a.m. on September 2, 1987.
The ILRT data was collected for twenty-four hours and the end of the ILRT was identified as 3:00 a.m. on September 3, 1987.
A superimposed leakage rate was established at 3:25 a.m. on September 3, 1987, and after a four-hour stabilization period, the collection of data for the ILRT verification test was performed from 7:30 a.m. to 2:00 p.m., for a six and one-half hour ILRT verification test.
The licensee's preliminary results for the twenty-four hour type A test, which did not include type B or C additions, was a total time calculated leakage rate of 0.042 wt. % per day with a 95% upper
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confidence limit (UCL) of 0.055 wt. % per day.
The licensee's maximum allowable leak rate for this test was 0.075 wt. % per day.
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For information only, a mass point analysis provided a calculated leak rate of 0.049 wt. % per day with a 95% UCL of 0.051 wt. % per day.
A six and one-half hour verification test was performed with
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an imposed leak rate of approximately 6.2 standard cubic feet per j
minute (SCFM) or 0.1%/ day of containment air mass.
The licensee verification test produced a total time calculated leak rate of 0.133 wt. % per day, with 95% UCL of 0.232 wt. % per day.
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.provided an acceptance criteria of'0.117 to 0.167'wt..% per day.
l fm Foriinformation only, the mass point analysis of.the verification
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. test' provided'a? calculated leak rate of- 0.134 wt.- % per day with a
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95% UCL of 0.148 wt. % per day,'and an acceptance criteria of'0.124
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to-0.174~wt.'%:per day. These preliminary results appear to be-
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pF" Within th'e latest allowed. acceptance criteria.
'r d.
Comment's on ItR'T-Procedure and Work Activities.
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The follo' wing comments'and recommendations were-discussed with the licensee representatives, who. stated that the inspector's.
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' obser'ations would b'e considered for possible change / inclusion-in v
.the subject procedures and work activities:
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(1)?: Configuration of Systems in Procedure
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.Theiinspector noted that as'of August'24, 1987, Revision 2 to
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ILRT Procedure SP.605-1 did not show the actual system
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configurations, for final system lineups.
This. caused delays-in
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performing system lineups. :The licensee stated that'since s
there had been major' system modifications and all'the design V
change notices had not received final acceptance'at the' time i
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the procedure was issued on August 3, 1987, they therefore were i
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'not included in the original system lineup sketches.
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.. inspector.' identified:that not only were some new valves not i
shown in the subject' sketches, but some valves originally s#
, identified for ILRT ' alignment were found to be' inaccessible for.
-valve operation by theilicensee' personnel sent out to perform the_. final ILRT system lineups.
The valve lineup crews found new valvas installed, old valves removed (or replaced with.a
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different design) or valves 30 feet above the floor with no I
ladder or' scaffolding erected to reach them.
l Rather than having the' valve lineup crews correcting the work
. procedure system lineups just before the test, this should have taken place before this.
(2) Motor Operated Valve Closure During the initial inspector's review of the valve system
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lineups, it was noted that some motor operated valves scheduled f
ic for positioning for the ILRT appeared to have last been positioned manually.
The manual handwheel gearing was still engaged, where it would have been in neutral if the valve had been positioned by normal operation (electrical, hydraulic or
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m air).
While all the local leak rate test (LLRT) and ILRT
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procedures identified that closure of containment isolation
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valves should be accomplished by normal operation and without I
any preliminary exercising or adjustments, the following was
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b noted during initial discussions held with licensee personnel I
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prior to final system lineups:
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Some licensee system lineup.walkdown personnel were under
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the impression that if a valve had a closure. light while
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performing the initial valve lineup, that the valve did
,not have to be' opened and closed by normal operation
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again.
Supervisor and control-room operators were aware
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. valves-had,to be cycled'again,..if plant conditions-permitted.
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R Walkdown personnel for system lineups did not normally check locar valve position indication for motor operated
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. val ves.- _They felt they.could not always trust the local.
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position ~ indicators, and since the motor operated valves
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had their limit switch positions verified by licensee test programs, that.the lights were the best method of valve
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' position verification.
As_an' example, it was noted during one of the: inspector's tours inside the containmer.t,.that valve HV26511 on' reference sketch S-20 was missing a local valve position indicator in its clear plastic tube and that the' local' valve position indicator (in~a plastic
. tube) on. valve HV26517 of reference sketch S-5 showed open, while the valve'had a closure' light.
Licensee,
. personnel l verified that valve HV26517 was closed.
Since:the earlier ILRT signoffs for ILRT system lineups had
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been' performed to Revision No. O of the ILRT procedure and~the T
question of how some motor operator valves had last'been t
positioned was brought up, the licensee made the decision to 2 start a new'ILRT system lineup walkdown using Revision No. 2 to the ILRT procedure.
This system lineup was also required
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'to verify all motoi operated valves were positioned by normal
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operation.
The inspector did not identify any motor operated valves that had been signed off in the earlier. system lineup walkdowns, that-had been left with their manual. handwheel gear engaged.
It was noted that some valves such as HP20597 on reference sketch S-24 were found,to have their handwheel manually engaged when they were checked prior to' positioning
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for this ILRT.
(3) local Valve Position Indication During the inspector's walkdown of system lineups, it was noted that some local valve position indications were very poor.
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Valve HV26517 (reference sketch S-5) showed the valve'open when it was closed, valve HV26511 (reference sketch
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S-20) was missing its local position indicator (from inside the
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l plartic tube); and many butterfly valves, such as NSWO88 and
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NSWO90 (reference sketch S-13) were closed with their local
> position indicator showing only two thirds closed.
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~(4) -Pen and Ink Changes to Procedures
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Some of the signoff sheets for system lineups in the ILRT procedure and local leak rate test sheets had pen and ink
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changes that were initialed but not dated.
The inspector
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identified examples of these cases to tre licensee.
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licensee corrected the examples' identified in the ILRT procedure and stated.they would see what additional actions.
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changes'to'an official data sheet.
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(5)
Local Leak Rate Test (LLRT) Data Sheets During this review, the inspector identified th' t.some of the a
earlier LLRT data sheets were not very clear and that it appeared that the original licensee personne1' filling them out had trouble using them.
These sheets contain pen and ink
, changes, and clarification notes added by the reviewing i
supervisor.
The format of,the latest LLRT data sheets had been I
changed with additional clarification sketches or writeups added, and appeared to provide a better layout of what was being tested and how it was to be tested.
The licensee identified that they were aware of this problem and would try to get all these LLRT procedures / data sheets updated as soon as possible.
(6) Normal Containment Ventilation System Operation and Additional Dew Cell Installation Based on the delays experienced during this ILRT test, as the result of high dew point temperatures above the sixty-six foot i
elevation and the installation of only one dew cell in this area, it appears the licensee might consider the following:
Installation of additional dew cells above the sixty-six foot elevation.
Operation of normal containment ventilation system fans during pressurization, the ILRT and the verification test.
While there were no violations in the above discussed items and the test was performed satisfactory, a number of weaknesses were observed.
It appears additional management attention is required in some of these areas.
I 3.
(Closed) IE Information Notice No. 85-71:
Containment Integrated Leak i
Rate Tests This Notice provided additional NRC information on containment Integrated Leak Rate Tests (ILRTs).
The inspector reviewed the following documents:
l Integrated Leakage Rate Test Procedure, SP.605.
-Local Leakage Rate Test Procedure, SP.422A.
Memorandum from G. Paptzum to Shirley Kubo on IE Information Notice NO. 85-71, dated August 4, 1987.
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'S *s Based on"the1 review of~the above documentsiand discussions held With thel
licensee ' personnel',.. it appears that:the_ licensee has taken:! appropriate
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This11temlsclosed.
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' -42 Exit Meeting >
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..The insp'ector met.with the. licensee management representatives denoted.in
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The scope of the: inspection and the
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inspector's findings"up to the timeTof_ the meeting, as noted in ~this :
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report,Lwere discussed..-At this' meeting,.the inspector also: identified.
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,~thatL additional -information.on IE Information Notice No.: 85-71: had.been
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'obtained and'other ILRT:information requested, and that'this material
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. would: be reviewed.in the-_ region and the inspector's findings documented
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