ML20057C594
| ML20057C594 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 09/09/1993 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML20057C577 | List: |
| References | |
| 50-528-93-29, 50-529-93-29, 50-530-93-29, EA-93-218, NUDOCS 9309290145 | |
| Download: ML20057C594 (3) | |
Text
!
U.S. NUCLEAR REGULATORY COMMISSION REGION V 50-528/93-29;50-529/93-29;50-530/93-29 Report Nos:
License Nos:
NPF-41, HPF-51, NPF-74 Arizona Public Service Company Licensee:
P. O. Box 53999, Sta. 9012 Phoenix, Arizona 85072-3999 Palo Verde Nuclear Generating Station Facility:
Units 1, 2, and 3 Inspection Location:
Wintersburg, Arizona Inspection Duration:
June 21 to July 9, 1993 7-7-93 Inspected by:
]a
~ c m a.
Date Signed ocynegra, RadKtion Specialist R.
f.<W f4 8 w 2 93 N. Mamish, Radiation Specialist Date Signed ffL
'/- 8 4 3 L. Coblentz, Sr Hadiat/ ion Specialist 6 ate Signed 9 hf_3_
Approved by:
i ka Date Signed k
Facilities Radiological [ Protection Branch n James H. Reese, Chief Summary:
Routine unannounced inspection of follow-up items, external Areas Inspected:
exposure control, internal exposure control, control of radioactive materials, radiation monitoring system (RMS), and primary-to-secondary leak rate methods.
Inspection Procedures 92701, 92702, 83729, and 84750 were used.
Deficiencies were identified regarding source leak testing, RMS Results:
Three procedure adherence, and primary-to-secondary. leak rate methods.
violations and one non-cited violation were identified. The first violation identified involved three examples of failure to follow radiation monitoring system procedures (sections 2 and 3), the second violation was issued for a deficient source leak test (section 5.a.1), and the third violation involved failure to correct a condition adverse to quality (section 7).
In addition, a non-cited violation of 10 CFR 19.11 was identified (section 5.c).
9309290145 930908 DR ADOCK 05000528 PDR.
I DETAILS-i 1.
Persons Contacted r
Licensee R. Adney, Plant Manager, Unit 3 K. Akers,: Technical Specialist III, Quality Audits & Monitoring
- S. Bauer, Senior Engineer, Nuclear Regulatory Affairs
- T. Bradish, Manager, Nuclear P,egulatory Affairs i
K. Coon, Senior Technical Advisor, Unit 2 Radiation Protection
- J. Draper, Site Representative, Southern California Edison D. Elkinton, Senior Technical Specialist, Quality Audits & Monitoring
- R. Flood, Plant Manager, Unit 2
- R. Fountain, Supervisor, Quality Audits & Monitoring
.j
- F. Gowers, Site Representative, El Paso Electric
- P. Guay, Manager, Unit 3 Chemistry T. Haggard, Sr. Radiation Protection Technician, Radiation Protection Services
- R. Henry, Site Representative, Salt River Project -
T. Hillmer, Consultant, Nuclear Safety W. Hoey, Manager, Radiation Protection Technical Services P. Hughes, General Manager, Radiation Protection V. Huntsman, Manager, Radiation Protection Support Services G. Hurley, Supervisor, Radioactive Material Control i
- L. Johnson, Manager, Unit 2 Chemistry J. King, Supervisor, Unit 1 Chemistry i
D. Leech, Supervisor, Quality Audits & Monitoring
- H. Lesan, Sr. Advisor, RMS Technical Services M. McKinley, Technical Advisor, Unit 2 Radiation Protection
- T. Murphy, Supervisor, Site Chemistry Support A. Ogurek, Consultant, Nuclear Oversight
- G. Overbeck, Director, Site Technical Services i
- W. Pierson, Manager, Unit I Chemistry l
C. Podgurski, Technical Advisor, Radiation Protection Technical Support
- F. Riedel, Operations Manager
- J. Scott, Assistant Plant Manager, Unit 3
- G. Shanker, Manager, Station Operating Experience Department
)
J. Shawver, Sr. Chemistry Advisor, Chemistry Technical Services M. Shea, Manager, Unit 2 Radiation Protection J. Sills, Manager, Unit 1 Radiation Protection l
- D Sneed, Supervisor, Unit 2 Effluents W. Sneed, Manager, Unit 3 Radiation Protection
- R. Sorensen, Manager, Site Chemistry Support C. Spell, Supervisor, ALARA i
L. Thorpe, Advisor, Chemistry Technical Services i
NRC
- J. Sloan, Senior Resident Inspector Denotes the individuals that attended the exit meeting held July 9, q
1993.
l 1
2 The inspectors held discussions with other personnel during the inspection.
j 1
2.
Follow-up of AIT Items (92701)
On March 15, 1993, an Augmented Inspection Team (AIT) was chartered to review the Unit 2 steam generator tube rupture (SGTR) event that occurred i
on March 14, 1993. The inspectors followed up on items identified by the AIT in Inspection Report No. 50-529/93-14 that appeared to be in violation of Technical Specification (TS) 6.8.1.
TS 6.8.1 requires procedures to be established, implemented, and -
maintained as recommended in Appendix A of Regulatory Guide (RG) 1.33, l
February 1978. RG 1.33, Appendix A, Section 7.g recommends procedures for process radiation monitoring system operation. The AIT report identified several examples of licensee personnel not following radiation monitoring system procedures.
a.
RU-15 Undocumented Alarm Setpoint Change f
Prior to the event, on March 14, 1993, the Unit 2 control room received several alarms on radiation monitor RU-15 (waste gas area combined ventilation exhaust monitor) due to reactor coolant system (RCS) gas stripper operation. The " alert" alarm setpoint was set at -
-l 1.4 E-6 uti/cc during this time. A Radiation Monitoring System (RMS) technician raised the alarm setpoint on RU-15 because the alarms became a nuisance to control room operators.
a Setpoint changes for non-effluent radiation monitors were controlled by procedure 74RM-9EF42, " Radiation Monitor Alarm Setpoint i
Determination."
Section 6 of the procedure stated the following-i 4
The basis for the setpoint shall be documented and the setpoint change processed in accordance with l
Section 9.0.
For all noble gas monitors except RU l and 30, the basis for the setpoint change shall require review and concurrence from the Unit Radiation Protection Manager or designee prior to implementation.
l The procedure further stated that these setpoints shall be controlled using Appendix J, and the bases for the setpoints shall be documented using Appendix K.
i The AIT identified that on March 14, 1993, at 3:13 am, and
-l again at 3:48 am, a Unit 2 RMS technician changed the " alert" and "high" alarm setpoints on RU-15, and prior to implementing the changes, failed to perform the following required actions:
Obtain Unit 2 RPM's review and approval of the revised setpoints.
l l
I 3
t Document the changes in Appendix J.
i Document the bases for the changes in Appendix K.
i Failure to follow procedure 74RM-9EF42, is a violation of Technical 3
Specification 6.8.1. (50-529/93-29-01) i RU-140 Alarm Response by RMS Technician b.
i 14, 1993, at 4:43 am, the l
The AIT report documented that on March Unit 2 control room received a main steam line "high" radiation In accordance with alarm alarm on RU-140 radiation monitor.
response procedure 74RM-9EF41, Revision 0, " Radiation Monitoring System Alarm Response," control room personnel acknowledged the Procedure 74RM-9EF41 alarm and notified the RMS technician.
l required the RMS technician to verify the monit Protection and the Shift Supervisor. -The RMS technician became distracted by other duties and did not verify the radiation monitor's database for proper setpoints and conversions factors, and' ;
did not notify the Shift Supervisor.
l This is another example of a violation of Technical Specification l
6.8.1. (50-529/93-29-01)
RU-141 Out of Calibration c.
14, 1993, During the SG tube rupture event, at 11:16 am, on March the licensee took a grab sample from the Unit 2 condenser vacuum 2
exhaust to prepare a radioactive gaseous release p l
The grab sample results indicated a Offsite Dose Assessment."
This discrepancy between the monitor reading and. sa.
of calibration and was non-conservative in its indications.
l 18, 1993. The The licensee took corrective actions on March immediate corrective action taken was to lower the alarm setpoints Other corrective actions included troubleshooting the failed monitor and initiating Condition / Report Disposition Request on RU-141.
(CRDR) Number 9-3-0216 to investigate the problem. The licensee later reported that the failure of RU 141 was due to an equipment-
,4 failure in the circuitry.
The inspectors performed a records review and noted that on March 5 1993, the licensee had taken a condenser vacuum exhaust gas gr sample following maintenance work on RU-141.
that gamma isotopic analyses showed that the condenser vacuum exhaust monitor RU-141 readings were biased low by a factor of approximately 6; however, at the time of analysis, the licensee h not recognized this discrepancy.
j e
4 Procedure 74RM-9EF20 required the licensee to review the gamma isotopic results for reasonableness and accuracy, and to resolve any discrepancies by either reanalyzing the counting data, recounting the sample, re-sampling, or taking any other appropriate actions.
The inspectors concluded that the licensee's failure to adequately review the results of the analyses resulted in a missed opportunity to identify that RU-141 was out of calibration.
Two examples of a violation of HRC requirements were identified.
3.
Follow-up of Open Items (52701)
Item 50-529/93-18-07 (Closed): Response to an RU-15 Alarm a.
As the result of observations made during a previous inspection, the inspectors had asked the licensee to review the responses by plant personnel to a May 4,1993, alarm on RU-15, a Radwaste Building Based on licensee discussions and documentation, Exhaust Monitor.
the inspectors noted the following points:
RU-15 had first alarmed at 8:50 am, on May 4,1993, with both (1) the "high" and " alert" alarms. The presence of the "high" alarm locked in the local monitor alarm.
Subsequent alarms The
(" alert" only) occurred at 9:31 a.m. and at 12:53 p.m.
local alarm was not cleared until 4:30 p.m. (7. hours, 40 minutes later), approximately 30 minutes after the inspectors found the local alarm alarming and covered over with tape.
I A memorandum to all site personnel, signed by the Vice President, Nuclear, had been issued on May 10, 1993, regarding l
(2) the inappropriateness of covering an audible RMS alarm.
1 In a memorandum dated July 8,1993, the Unit 2 Effluents (3)
Supervisor concluded that alarm response had been in accordance The inspectors noted, with 74RM-9EF41, "RMS Alarm Response."
however, that this procedure requires radiation protection (RP) j personnel to perform radiation surveys and/or grab samples in.
The the vicinity of the alarming monitor's detector.
inspectors also noted that the Unit 2 Effluents Supervisor had not verified whether, in fact, any such radiation surveys had been done.
The July 8,1993, memorandum also noted that Procedure 74RM-(4)
The memorandum did not 9EF41 did not address local alarms.
j reach any conclusion as to whether this aspect of the procedure was adequate, nor whether the lack of response to the local alarm was appropriate.
)
~ -
~
5 i
(5) Training Handout NCE 10-02, "RMS Surveillance Tests and Alarm Response," gave an overview of alarm response procedures and actions. The inspectors noted the following quote from the handout-Monitors also may have a separate, local alarm indication that is [ sic] and therefore may have to be acknowledged at the microcomputer locally.... It is important that these are acknowledged locally, in a timely manner, such that workers are not de-sensitized to any monitor alarms due to monitors being continual alarm. [ sic]
I (6) At the exit interview, the inspectors observed that certain aspects of the alarm response actions had still not been verified. The licensee reopened the investigation of this matter, and determined several additional points:
(a) At the time of the first RU-15 alarm, an operations computer support (0CS) technician was performing a quarterly functional check on RU-143/144. When RU-15 alarmed, the OCS technician informed a control room operator. The operator acknowledged the alarm, but failed to verify the alarm, inform personnel of possible hazards, or inform the effluents group of the alarm, as required by the alarm response procedure.
(b) During the time the monitor was alarming locally, over 200 plant personnel (including members of Operations, RP, Chemistry, and management) walked past the alarm.
No corrective action was taken until the condition was identified by the inspectors.
(c) The licensee also determined that several additional corrective actions were warranted. These included evaluating the event summary for inclusion.in industry events training, preparing labels for the monitors to notify Chemistry or Operations of local alarm conditions, and enhancing the alarm response procedure.
The inspectors noted that TS 6.8.1 requires procedures to be established, implemented, and maintained as recommended in Appendix A of Regulatory Guide (RG) 1.33, February 1978. RG'1.33, Appendix A, Section 7 9 recommends procedures for process radiation
)
monitoring system'(RMS) operation.
The inspectors concluded that the failure to follow the RMS alarm response procedure, 74RM-9EF41, as denoted above, constituted a third example of a violation of TS 6.8.1 (50-5?9/93-29-01).
One example of a violation of NRC requirements was identified.
-i.------.er
i 4
l 6
i 4.
Follow-up of Items of Noncompliance (92702) a.
Item 50-528/93-03-02 (Closed): This violation' involved 10 examples of failure to follow Radiation Protection (RP) procedures for As Low
.l" As Reasonably Achievable (ALARA), Radiation' Exposure Permits (REP),
and resin _ dewatering during a resin transfer. The licensee's corrective action included implementing an RP manager and supervisor internal self assessment program, establishing criteria for job site j
supervisory involvement, and clarifying RP technician and i
supervisory involvement in pre-job briefings.
In discussing the self assessment program with the licensee, the inspectors did not identify any specific. concerns. The inspectors had no further
[
questions in this area.
b.
Item 50-528/93-03-03 (Closed): This violation concerned the failure to perform a survey, as required by 10 CFR 20.201(b), to assure l
compliance with the whole body radiation exposure limits of 10 CFR 20.101. As corrective action, the licensee revised REP pre-job planning procedures and briefed RP technicians on the event.
Additionally, the licensee developed "Model REPS" (similar to those being used for refueling outage activities) to provide additional guidance for performing surveys. During the inspection, the inspectors reviewed the revised procedures, and verified by interviews, that RP technicians had been briefed on the event. The i
inspectors had no further questions in this matter.
j i
c.
Item 50-528/93-03-04 (Closed): This violati'on involved the failure to supply appropriate personnel monitoring equipment (i.e.,
i dosimetry) for monitoring the portion of the body receiving the highest whole body dose. The licensee's corrective action included implementing an RP manager and supervisor internal self assessment i
program, establishing criteria for job site supervisory involvement, and clarifying RP technician and supervisory involvement in pre-job l
briefings. Additionally, the licensee developed "Model REPS" 1
i (similar to those used for refueling outage activities) to provide additional guidance for performing surveys.
The inspectors reviewed the revised procedures, and verified by interviews that RP technicians had been briefed on the event.
In t
discussing the self assessment program with the licensee, the inspectors did not note specific problems. The inspectors had no further questions in this area.
d.
Item 50-528/93-03-05 (Closed): This violation concerned the failure to limit whole body radiation dose to 1.25 rem per calendar quarter without meeting the conditions of 10'CFR 20.101(b). As corrective action, the licensee lowered the administrative quarterly exposure limit to 300 mrem (limit may be raised with management approval),
and improved the method of processing NRC-4 forms. Workers that accumulated 270 mrem (i.e., 90% of limit) would be restricted from
P 7
entering the Radiation Controlled Area (RCA) if they failed to sign their Form NRC-4 after receiving written r otif, cation. The i
inspectors had no further questions in this matter.
Further corrective actions for the items of noncompliance listed above These corrective actions included stressing the were implemented.
significance of body positioning and reliance on alarming dosimeters The long term effectiveness i
during continuing training for RP personnel.
of these corrective actions will be periodically reviewed as part of the routine inspection program.
5.
Occupational Exposure Durina Extended Outages (83729)
The inspectors evaluated the licensee's occupational radiation. protection program by reviewing the licensee's procedures, discussions with licensee Specifically, the inspectors staff, and observation of work in progress.
reviewed the licensee's programs for control of radioactive material and internal exposure, and conducted facility tours.
i i
Control of Radioactive Material I
a.
The inspectors examined' attributes of the licensee's programs for control of radioactive material by reviewing the licensee's programs for control and leak testing of radioactive sources and control of personnel contamination.
1 (1) Control and Leak Testing of Radioactive Sources The licensee program for control of radioactive sources consisted of a source tracking system which included a computerized data base that tracked and maintained records of all radioactive sources, and a source checkout log to maintain control and accountability. Sources were leak checked on a i
semiannual basis as required by the TS. Additionally, the l
licensee performed leak checks on radioactive sources upon receipt at the central warehouse.
The inspectors examined licensee source checkout logs, source inventory lists (i.e., computerized data base), and leak check j
records. Using the source inventory list and source checkout logs, the inspectors selected a sampling of sources and physically verified that the location of sources was consistent However, in reviewing the leak with the records reviewed.
check records and technical requirements found in licensee
)
procedures, the inspectors noted the following:
(a) Observed Condition The licensee's method for detecting leakage of radioactive sources had not' been adequate for all sources.
Specifically, the inspectors noted that semiannual leak check swipe samples of a Cd-109 source and an Fe-55 source
"-W
4 t
8 had been counted using an instrument (i.e., Eberline model BC-4) that would not have deiccted the 1,000 disintegrations per minute (dpm) limit outlined in licensee Procedure 75AC-9RP05, " Source Control," Revision 2.
i Additionally, the inspectors noted that reactor engineering procedures did 60t specifically address controls to ensure that startup sources and fission detector sources were leak checked 31 days prior to being subjected to core flux (or installed in. he core), and i
t following repair or maintenance of the source or detector.
In touring the warehouse, the inspectors found four excore detectors that had been stored and questioned the licensee if they had been leak checked upon receipt, and if excore detectors had been moved to the units' cores.
(b)
Licensee Requirements TS 6.8.1 requires that written procedures be established, j
implemented, and maintained covering the applicable i
procedures recommended in Appendix A of Regulatory Guide (RG) 1.33, Revision 2, February 1978.
RG 1.33, Appendix A, Section 7.e(4) recommends procedures for contamination control.
j Licensee Procedure 75RP-9MC02, " Leak Testing and Inventory of Radioactive Sources," Revision 1, dated February 1, 1992, Section 3.2.1 establishes general leak test requirements. Section 3.2.1.7 requires the individual performing leak tests to use leak testing methods capable of detecting, on the test sample, a minimum of 1000 dpm of removable beta / gamma contamination and 20 dpm of removable alpha contamination.
(c)
Licensee Assessment Licensee technichi staff acknowledged the inspectors' observations, but added that they believed the Fe-55 i
source had been leak checked using a liquid scintillation counter, a more efficient and appropriate counter. -During a subsequent discussion with the inspectors, the licensee provided the inspectors with a leak check record of the i
Fe-55 source and indicated that the cd-109 source would be leak checked using a me' hod that would ensure compliance with the facility's requirements.
Additionally, the licensee informed the inspectors that reactor engineering procedures would be revised to ensure that startup sources and fission detector sources are leak e-y
,m
,,o
l l
g checked 31 days prior to being subjected to core flux (or installed in the core), and following repair or maintenance of the source or detector.
(d)
Licensee Corrective Actions During a telephone conversation with the inspectors on July 19,1993, the licensee stated that the cd-109 and the Fe-55 sources were re-checked and verified not to be leaking, and Procedure 75RP-9MC02 was revised and approved on June 29, 1993, to ensure the appropriate instruments are used to check for leakage of radioactive sources.
The licensee stated that reactor engineering Procedure 72AC-9NF01, " Control of SNM Transfer and Inventory," was revised and approved on July 13, 1993, to notify Radiation Protection Personnel to perform leak tests. The licensee t
added that all excore detectors stored at the warehouse l
had been leak checked upon receipt, and that no fission detectors had been moved from the warehouse to the units' reactor cores in the past three years.
i (e)
NRC Conclusion The inspectors concluded that the licensee failed to implement the leak test requirement found in 75RP-9MC02, Section 3.2.1,7, in that leak testing methods were i
incapable of detecting (on the semiannual Cd-109 leak check) a minimum of 1000 dpm of removable beta / gamma contamination.
Failure to implement 75RP-9MC02 is a violation of TS 6.8.1 (50-528/93-29-02).
The inspectors noted, however, that the licensee's immediate corrective actions, including procedure changes to prevent recurrence, had been completed within a reasonable time; therefore, no response is required for this violation.
(2)
Personnel Contamination Controls l
The inspectors reviewed the licensee's program for controlling personnel contamination by discussing the program with licensee staff, and reviewing licensee procedures and records.
The inspectors reviewed the following licensee procedures:
75RP-9RP04, " Personnel Decontamination," Rev.1.02 75RP-9RP05, " Contamination Dose Evaluation," Rev. I j
The inspectors noted that the licensee's program required the initiation of a contamination report and an investigation for skin / clothing contaminations that exceeded 1000 dpm f
10 skin / clothing contaminations that exceeded 1000 dpm (disintegrations per minute), as measured.with an HP-210 probe or equivalent.
If monitoring indicated that the contamination was greater than 20,000 dpm per probe area, a preliminary skin
'i dose evaluation was performed.
If the preliminary skin dose evaluation resulted in a skin dose equal to, or greater than 750 mrem, a more detailed dose evaluation was performed by the radiological engineering group.
i The inspectors reviewed the licensee's computerized data base of personnel contamination events for the Unit 2 outage and a i
selection of personnel contamination reports and skin dose evaluations. As of June 23, 1993, the licensee had initiated 65 personnel contamination reports.
Based on the records l
reviewed, personnel contamination reports were consistent with
?
personnel contamination logs, and skin dose evaluations were accurate and technically sound..No specific discrepancies were noted.
1 b.
Internal Exposure Controls The inspectors evaluated aspects of the licensee's programs for control of internal exposure by reviewing the licensee's respiratory protection and air sampling programs.
(1) Respiratory Protection Program The inspectors evaluated the licensee's practices for controlling respiratory protection equipment by discussing the program with licensee staff, reviewing licensee procedures and records, and observing work in progress. The inspectors noted that the licensee had established methods for inspection, maintenance, and repair of respirators. Additionally, controls and procedures had been instituted to prevent issuing respirators to workers who had not been properly trained, fit-tested, and medically approved by a physician.
The inspectors toured the respirator maintenance and storage facilities, and observed workers getting fit-tested. No concerns were identified.
(2) Air Sampling Program The inspectors evaluated the licensee's air sampling program by reviewing licensee procedures and records, and holding discussions with licensee staff. The following licensee procedures were reviewed-i 75RP-9RP07, " Radiological Surveys," Rev. 2.04 75RP-9RP21, " Airborne Evaluation," Rev.I.03 i
I
l
~
11 The inspectors noted that the licensee's air sampling program consisted of routine and special air sampling.
Routine air i
sampling was performed at preselected locations inside the Radiation Controlled Area (RCA) by using continuous air monitors and grab samples.
Special air sampling was performed for work activities that had the potential for creating.
airborne radioactivity concentrations of greater than or equal to 10 per cent of the Maximum Permissible Concentration (MPC).
The inspectors reviewed air sampling and intake evaluation records of recent jobs involving work on the Unit 2 upper guide structure. The air samples were counted in accordance with licensee procedures, and the results were properly reviewed for technical content. Workers receiving minor uptakes had been whole-body counted as necessary, and internal exposure tracking had been performed as required. No discrepancies were noted.
c.
Facility Tours The inspectors performed independent direct radiation measurements and conducted tours of selected areas of the licensee's RCA.
The following observations were noted:
(1)
Bulletin boards located at entrances to buildings did not contain Notices of Violation (NOVs) involving radiological working conditions.
In discussions with the inspectors, the licensee staff stated that they believed they were in i
compliance with Part 19.11, because the cover letters to inspection reports were posted.
10 CFR 19.11(4) states in part that any notice of violation involving radiological working conditions and any response from the licensee shall be posted.
The inspectors noted the clear language of 10 CFR 19.11 requiring the posting of NOVs, and the licensee stated that the actual notices would be posted on the bulletin boards as required.
Failure to follow the requirements of 10 CFR 19.11(4) was noted as a violation. However, because the criteria of Section VII.B of the Enforcement Manual were satisfied, this violation will not be cited (50-528/93-29-03).
(2) The Unit 2 waste feed pump room was found to be cluttered with hoses and bags containing hot particle waste.
(3) A high radiation area entrance into the Unit 3, 120' elevation purification valve gallery was not barricaded with snow fencing i
(i.e., bright orange netting to make the area more conspicuous).
l l
j
?
12 The inspectors noted that, with the exceptions noted above, radioactive materials observed were appropriately labeled and controlled.
Posting of radiation areas, high radiation areas, and i
radioactive material storage areas were appropriate in the areas j
toured.
In subsequent tours, the inspectors noted that all of the observed discrepancies had been corrected.
The inspectors concluded that the licensee's program.for controlling occupational exposures, in the aspects observed, was adequate in protecting the health and safety of licensee employees.
F One violation and one non-cited violation of NRC requirements was identified.
6.
Radiation Monitoring System (84750)
The' inspectors examined this program area by interviewing cognizant l
personnel, reviewing applicable licensee documentation, conducting system walkdowns, and observing work in progress. Observations were made regarding audits, system modifications, and surveillance testing.
a.
Audits The inspectors reviewed Audit Report 93-004, " Radiological Environmental Monitoring Program," dated May 10, 1993, in the aspects related to the radiation monitoring system (RMS). The auditors had reviewed controls for radioactive gaseous effluent releases, in response to deficiencies noted during the recent steam generator tube rupture event in Unit 2.
l The audit appearec to have been thorough and probing.
No significant deficiencies were identified regarding RMS maintenance or operations.
The audit identified a " potential need" for enhancements to the RMS technician training program.
b.
System Modifications In system walkdowns and discussions with the system engineer and chemistry standards representative, the inspectors revieved the following system modifications, scheduled for eventual completion in i
all three units 1
(1) Due to problems with moisture intrusion in the Turbine Building i
environment, a temporary modification had been installed on the condenser vacuum exhaust monitors, moving the sample point to a location outside the sampling pig.
This change reduced moisture accumulation and allowed heat tracing to be installed.
As a permanent system enhancement, the licensee was changing i
these monitors from off-line systems to in-line processors.
Effluent exhaust gases were also being re-routed to the. plant i
vent, for final monitoring by the plant vent monitors prior to 4
13 1
atmospheric release. This modification had been completed in
.l Unit 2.
(2) The letdown process monitor (RT-204) was being removed and replaced with an ion chamber to be monitored as Channel 4 of RU-155.
The change was being performed due to long-term problems with RT-204 operability.
This change had been completed in Units 2 and 3 (Unit 2 still required start-up physics testing).
(3) Modifications were in progress on the plant vent monitors to separate RU-144 (high range) and RU-143 (normal range). This change was to allow RU-144 to continue to run while RU-143 was I
out of service (such as during normal maintenance). The change, which had been completed in Units 1 and 2, included software modifications and adding a bypass line, a flow l
indicator, and several valves.
J (4) A similar modification to that in "(3)," above, was planned for i
the fuel handling building exhaust monitors, RU-145 (normal range) and RU-146 (high range). This change had not yet been completed in any of the units.
l (5) The containment atmosphere monitor was being modified by removing the hydrometer function (which had a poor operating history) from Channel 4, and installing a new algorithm to i
monitor the particulate channel rate of change. This change l
had been completed in Unit 2.
The inspectors reviewed the overall system functionality and performance enhancements associated with these changes, in relation t
to descriptions given in Technical Specifications (TSs), the Updated j
Final Safety Analysis Report (UFSAR), and industry standards.
In t
the aspects reviewed, no loss of essential system functions or lessening of overall system performance was detected. Appropriate engineering controls and safety reviews had been applied in all cases reviewed.
c.
Surveillance Testing i
The following surveillance tests (STs) were reviewed:
Work Order (WO) 00460906, ST Procedure 36ST-95Q05, portions t
related to calibration of RU-1 and RU-12, Unit 1 l
WO 00568693, ST Procedure 74ST-95Q21, portions related to calibration of RU-29 and RU-30, Unit 1 WO 00571196, ST Procedure 74ST-9SQ22, portions related to calibration of RU-37, Unit 3 WO 00573044, ST Procedure 74ST-9SQ23, " Radiation Monitoring Calibration Test for New Scope Area Monitors," Unit 2 W0 00580074, ST Procedure 74ST-95Q26, " Radiation Monitoring Calibration Test for RU-143." Unit 3 i
i
[
a
t 14 W0 00580088, ST Procedure 74ST-95Q27, " Radiation Monitoring Calibration Test for RU-144," Unit 3 W0 00594945,-ST Procedure 74ST-95021, " Radiation Monitoring i
Calibration Test for Baseline Monitors," Unit 2 W0 00599891, ST Procedure 74ST-95Q24, " Radiation Monitoring Calibration Test for RU-141," Unit 1 W0 00599909, ST Procedure 74ST-9SQ25, " Radiation Monitoring Calibration Test for RU-142," Unit 1 In the areas reviewed, calibrations had been performed in accordance i
with applicable procedures, at/or exceeding the frequencies specified in TSs and the Offsite Dose Calculation Manual, as applicable.
As-found out-of-tolerances had been corrected on the spot, or. referred to the work group supervisor (WGS) for disposition. Although procedures were not specific _ in the ' actions required by the WGS for as-found out-of-tolerances, discussions with two WGSs revealed an effective level of consistency and control l
applied to calibration discrepancies.
The licensee's overall program for operating and maintaining the radiation monitoring system, in the aspects observed, was adequate in 1
meeting the licensee's safety objectives.
l t
7.
Steam Generator Tube Leak Rate Determination (84750)
I a.
Background
Through discussians with licensee personnel, during the first week of this inspection on June 21-25, 1993, the inspectors noted that methods usea to determine primary-to-secondary system leakage appeared te be flawed. (Flaws were noted in both the method based upon tritium concentration and the method based upon iodine concentration. Since the licensee was using the iodine method as the primary method, the inspector focused the remainder of this l
review on that method.) Based on initial information obtained, one particular method involving measurement of 1-131 in the steam generator may have caused the licensee to under-estimate the steam generator tube leakage rate by approximately a factor of ten.
Chemistry personnel indicated to the inspectors that the licensee started working on the problem after the Unit 2 steam generator tube :
rupture event. At the conclusion of the first week of inspection, the licensee continued to evaluate the problem.
Prior to this inspection, the licensee had not indicated to the NRC that the licensee had a problem in accurately determining primary-to-secondary leakage.
b.
Estimated Versus Actual Leak Rates The inspectors returned to the Palo Verde site during the week of July 6-9,1993, to look further into the steam generator tube. leak rate issue and to develop more information. The licensee's investigation concluded that the most reliable method for
l l
15 determining steam generator tube leak rates was by measuring Xe-133 in condenser vacuum exhaust grab samples. The,other two units have discontinued using the I-131 method for leak rate determination, and permanent procedure changes are being drafted.
i Recalculating leak rates using the Xe-133 method and available data, the licensee found that on March 4,1993, the Unit 2 SG #2 tube leak l
increased from 2-5 gallons per day (gpd) to approximately 105 gpd over about two hours. The leak rate peaked and slowly decreased during the next two days and eventually plateaued at about 20-30 gpd. The increase in leakage rate occurred concurrently with a small reactor coolant system (RCS) pressure increase presumably caused by a charging pump surveillance test being performed at the I
time.
The extent of the licensee's underestimation of the SG #2 leak rates was gleaned from information in the Unit 2 Chemistry log and other Chemistry log entries indicated March 4,1993, leak rate sources.
values, reported to the control room, of 9.83 gpd at 4:45 am, and 9.34 gpd at 5:42 am.
Recalculated leak rates using the Xe-133 method later estimated the true leak rates to be about 105 gpd and 87 gpd, respectively.
On March 4, 1993, at 4:26 am, the entry in the chemistry log was 18.1 gpd for the primary-to-secondary leak rate using condenser vacuum exhaust radiation monitor (RV-141) readings, but it appeared that this information was not given to the control room operators.
Licensee personnel were not aware at the time that RU-141 was out of calibration and reading low by approximately a factor of 6.. The corrected leak rate based on this chemistry log entry was therefore l
approximately 109 gpd, which agrees with the recalculated leak rate using the Xe-133 gas grab sample method.
c.
Licensee Prior Knowledge of Potential Non-Conservatism Additional information revealed that since at least December 1992, the licensee had been or should have been aware of the potential shortcomings of its primary method (I-131) for calculating primary-to-secondary system leakage.
In a letter to the Palo Verde Site Chemistry Manager dated December 10, 1992, Combustion Engineering (CE) indicated that the hotleg blowdown sample point being used to draw steam generator water samples appeared to be diluted by a factor ranging from 5 to 10.
CE also stated in the letter that the downtomer samples were more representative of.the steam generator bulk water than the hotleg blowdown samples.
Prior to January 20, 1993, the licensee sampled steam generator water at the hotleg blowdown sample point. The CE letter recommended changing the SG sample point from the' hotleg blowdown sample point to the downcomer sample point for routine surveillance of steam generator bulk water chemistry. After internal discussions regarding the CE recommendations, a memo was issued on 1
16 January 20, 1993, stating Palo Verde management's decision to change the sample point for chemical impurity analysis, but to continue using the potentially diluted sample point to measure radioactivity in the steam generators.
Palo Verde Unit 2 TS Limiting Condition for Operation (LCO) 3.7.1.4 requires that the specific activity of the secondary coolant system be less than or equal to 0.10 microcuries/ gram Dose Equivalent I-131. TS Surveillance Requirement 4.7.1.4 states that the specific activity of the secondary coolant system shall be determined to be within the limit once per 31 days, and gross activity once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Procedure 74ST-95G01, " Secondary System Activity Surveillance Test" implemented the TS requirements. The licensee's January 20, 1993, memo explained the reasoning for rejecting CE's recommendations, by stating: "74ST-95G01, Secondary System Activity Surveillance Test, will continue to be sampled using the hot leg sample point since it more accurately reflects the activity leaving the steam generator via blowdown and because of the potential impact on both the blowdown and condensate demineralizers." The inspectors l
questioned the licensee's reasoning, noting that the objective of procedure 74ST-95G01 was not to determine the impact on the demineralizers, but rather to determine compliance with the TS, l
... verifying that the specific activity of the secondary coolant is less than or equal to 0.10 uti/ gram Dose Equivalent I-131."
During a conference call between NRR, Region V, and the licensee on July 16, 1993, the licensee stated that it would continue to use the i
potentially diluted hotleg blowdown sampling point to assure compliance with the Technical Specifications.
In a later telephone conversation with licensee chemistry management, the inspectors learned that the licensee subsequently decided on July 18, 1993,
(
that it would change to the downcomer sample point for steam generator activity.
d.
Conclusions The inspector.s concluded that the licensee underestimated the Unit 2 steam generator tube leak rates by as much as a factor of 10 in some cases, and should have been aware that the primary method for determining SG leak rates was questionable.
10 CFR Part 50, Appendix B, Criterion XVI, " Corrective Actions,"
states in part:
" Measures shall be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and non-conformances are promptly identified and corrected."
Despite the licensee Chemistry Manager's receipt of a December 10, 1992 letter from Combustion Engineering identifying the potential for dilution of samples taken from the hot leg blowdown for secondary steam generator water chemistry, a condition adverse to quality, the licens"e failed to establish measures to assure that
'4' 17 the problem was corrected.
Failure to change the sample location for steam generator secondary water radioactivity measurements from the hot leg blowdown to another location, thus providing inaccurate results, is a violation of 10 CFR 50 Appendix B. (50-529/93-29-04)
The data reviewed by the inspectors included logs, computer plots from various radiation monitors, analysis results, and data from the Emergency Response Facility Data Acquisition System (ERFDAS). Based on the review, the inspectors concluded that the. licensee's methodology for estimating leakage was flawed.
However, even if it had not been flawed, there is no evidence to suggest that the licensee would have gotten advance warning of the tube rupture on March 14, 1993.
One violation was identified.
8.
Exit Interview The inspectors met with the individuals listed in Section 1 on June 25, 1993, and again at the conclusion of the inspection on July 9,1993. The scope and findings of the inspection were summarized, including deficiencies with the source leak testing, RMS procedure adherence, posting of NOVs, and primary-to-secondary leak rate methods.
The licensee acknowledged the inspectors' observations.