IR 05000282/1990015
| ML20058D080 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 10/25/1990 |
| From: | Hasse R, Langstaff R, Phillips M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20058D079 | List: |
| References | |
| 50-282-90-15, 50-306-90-16, NUDOCS 9011050306 | |
| Download: ML20058D080 (10) | |
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U.S. NUCLEAR RESULATORY COMMISSION REGION 111 Report No. 50-282/90015; 50-306/90016(DRS)
OccLet flos.
50-282; 50-306 Licenses No. DPR-42; DPR-60 Licensee: Northern States Power Company 414 Nicollet Mall Minneepolis, MN 55401 facility Name:
Prairie Island Nuclear Generating Station - Units 1 & 2 Inspection At: Welch, MN 55089 (Red Wing)
Inspection Conducted:
September 17 through October 5, 1990 Rlli Inspectors:
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/r /3r/fg R. A. Hasse Date'
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EK. Langsta'f t Date FC P.[put/ /t, N/ir /96 g//J Approved By:
Thillips, Chief Date
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Operational Programs Section Inspection Summary inspection conducted on Seatember 17 through October 5, 1990 Theport No.50-282/M015; 5 SM6/90016(DRS))
Areas Inspected:
Routine, announced inspection of design changes and modifications. This inspection was conducted in accordance with Inspection Module 37700.
Results:
No violations were identified. Corrective action on a previously identified violation in the area of procurement was not adequate to close the item.
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REPORT DETAILS
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Persons Contacted
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b Northern States' Power Company (NSP)
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E. Watzi, General Manager, Prairie Island Site L
M M. Sellman,. Plant. Manager P-D._Mendele, General Superintendent, Engineering _and Radiation Proter. tion
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>X D.!Dugstad,_ Engineering' Associate s
G'.!Foering,-Manager, Nuclear Projects. Department, P1
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M.,Klee; Superintendent, Quality Engineering h
.P. Kamman, Manager,' Nuclear _ Operations QA (PSQA)
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-G.'LBird,-Quality Supervisor-(PSQA)-
C.:Kinney, QA Specialist j
m-L-; Ganser, QA Specialist.
l G.jEckholt,' Site Licensing ~
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uT. Breene, Superintendent,1 Nuclear Engineerirg 4;
- Du fricke, Superintendent, Materials Engineering-
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' U. S. helear Regulatory Commission (NRC):
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--P' Hartmann, SD
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'DU Kosloff, RI m ;o y$
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.Other personnel.were contacted as a matter of routine during the 4/C 4 inspection.-
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1 A11 personnel listed:above attended the exit interview held on= 0ctober 5,
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- 2.
- . Licensee Action on Previous inspection' Findings-t
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- (0 pen)ViblationI(282/88-201-01;:306/88-201-01):
Inadequate evaluations
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ufor,use of 7 commercial grade. items (CGI) in safety;related systems. Thei
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zinspectorfound_n~o'specificcaseofinadequate-acceptanceactivities
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, Tduringlthis; inspection; however, weaknesses found in many CGI evaluations-yN ;y do notsprovide confidence that? commercial grade dedication acceptance
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- activities were'.always.well defined. :During the course of this-
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i :3 inspection, commercial grade? dedication program: procedures'were reviewed,~
(preparers of CGI evaluations-and receipt inspection _-personnel were interviewed.. receipt inspection and warehouse areas were inspected, and.
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j+approxima tely140% of the. licensee!s CGI. evaluat_ionsiwereireviewed.
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t A sample of specific items identified in inspection Reports No. 50-282/88-201;
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,No. 50-306/88-201 were reviewed for adequacy as detailed below.
Corrective actions were adequate and consistent with licensee commitments.
No additional concerns were identified with respect to these items.
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P0 D43835 - Material and adequacy for composite rupture discs was
confirmed through written communications with the vendor.
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. Analysis for seismic qualification of pressure switch
was performed.
The analysis was based on engineering judgment. As committed by the licensee (Northern States Power 1rdter, dated 6/20/89, toH.J. Miller,_DRS,RegionIll,NRC),theseismicqualification was downgraded to a pressure retaining function only.
Review by the
inspe tor, incluo;ng inspection of the installed pressure switch and associated mounting, confirmed that no further analysis, such as seismic calculations, was necessary.
The~ inspector reviewed the procedures used for the commercial grade
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dedication-process. These-procedures incorporated the methods outlined
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-in EPRI NP-5652, " Guideline for the Utilization of Commercial Grade items
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in Nuclear Safety Related Applicatiuns." Although the reservations noted in Generic Letter 89-02, which conditionally endorsed EPRI NP-5652, were i
not specifically< incorporated into the licensee's procedures, no evidence
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- of f acceptance activities contrary to Generic Letter 89-02 was found.
l The' licensee's testing procedure used for commercial grade dedication of
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molded case circuit breakers (MCCB), detailed in Commercial Grade
- Application' Evaluation PI-0018,.was consistent with the requirements
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outlined:in: Bulletin 88-10 except that terminal heat rise testing was
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i substituted for the " individual pole resistance or millivolt drop. test."
Thetsubstitution was consistent with licensee-commitments (discussed in
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Northern States Power letter, dated 7/12/89, to H. J. Miller, DRS,
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RegionLIIIT NRC).
The-MCCB'.s'which 'were upgraded to safety-related,
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.us ng-theidedication_ process, were procured during ple.. construction and i
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-had been used in non-safety related applications!in_ the plant.-
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' Several concerns, as outlined below, were identified w'ith respect to the
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CGl'evalu'ations.
In addition to determining whether commercial grade d
dedication is appropriate for-an item, the_ CGI: evaluations provide the l
engineering basis for acceptance activities and provide detailed receipt'
- inspection and testing;information necessary for acceptance..of:an item..
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For many CGI evdluations, the-licensee simplified the critical
characteristics to general' characteristics such as " dimensions,"
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" material," and:" electrical' properties." No further explanation, I
m such as which dimensions were cru.ical, was provided in the CGI-s
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Because the; critical characteristics determine what
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acceptance should-be. based on, the lack of detail and engineering j
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consideratio! in identification of critical characteristics provided a poor basis for defining appropriate acceptance activities.
Man,y OG1 evaluations did not explicitly state which characteristics
required inspection and what the associated acceptance criteria Was.
for example, many CGI evaluations specified that dimensions were to be inspected, but did not specify which dimensions were to be inspected and what the Wlerances for those dimehsions were.
In cases where standard preoperational testing was necesucry for
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acceptance of an item, the test requirements were not specified in CGI evaluations.
Consequently, the items were not tagged as requiring additional testing for acceptance.
Because the testing requirements necessary for acceptance were not defined in the CGI evaluations, the preoperational testing performed, while sufficient for operational
. testing, may have been inadequate for acceptance of the items.
The inspector noted that in cases where special testing, such as bench testing, was required, testing requirements were specified in the CGI evaluations. The items were specially tagged, and procedures required that warehouse personnel check to ensure there was a testing procedure for the items prior to release.
In some blanket CGI evaluations, i.e., evaluations applied to all
replacement parts of specific assemblies, the same critical characteristics were identified for all parts covered by the evaluation. However, in cases where little credit is taken for vendor QA programs, identification of critical characteristics for
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individual parts is necessary to ensure acceptance activities are appropriate.
These issues were: discussed with the licensee. -Pending further review and action by the licensee, this item will remain open.
(See Paragraph 4 for further discussion of this area.)
3.
Design Changes and Modifications The inspectors reviewed six permanent plant modifications and four temporary modifications to determine if they had been conducted in accordance with programmatic and regulatory requirements and if all technical issues had been adequately addressed.
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inspection Results The results of the inspection are presented in the following paragraphs.
(1) Modification 88LO67, "High Head Safety Injection (HHST) Pump Miniflow Increase This modification replaced the HHS1 pump miniflow orifice rated
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at 47 gpm at a total dynamic head (TDH) of 5100 feet with an orifice rated at 72 gpm. The modification resulted from a study conducted by HSP and the pump manufacturer in response to Bulletin NRCB 88-04 The purpose for increasing pump miniflow was to assure adequate pump protection during miniflow operation.
Since miniflow normally remains in operation during safety injection, this modification reduced total injection flow dvailable for accident mitigation. The inspector reviewed the impact of this reduction on the FSAR safety analyses.
For the LOCA analyses, the concern is the peak cladding temperature (PCT)
generated during the event.
For the large break LOCA (LBLOCA),
the existing FSAR analysis had used a sufficiently conservative injection flow to bound the new flow rates. Therefore, there was no impact on tne maximum PCT in the FSAR analysis.
While addressing the impact on tre small break LOCA (SBLOCA)
analysis. Westinghouse identified three inconsistencies in the current analysis: (1) The auxiliary feedwater (AFW) flow used
-_ as 400 gpm vs. 200 gpm that should have been used to meet w
10 CFR 50 Appendix A and K requirements; (2) The time required after AFW flow initiation to purge high enthalpy main feedwater from the shared piping was inadequately-accounted for; and, (3) the HHSI flows used assumed no flow inbalance between the branch injection lines while the technical specifications allow up to 20 gpm flow imbalance.
Westinghouse estimated that the correction of these inconsistencies would raise the PCT currently identified in the FSAR by a-maximum of_650 F.
The current value for the PCT is 1000 F.
Thus the addition of the 650 F still provided a significant margin to the safety limit specified in 10 CFR 50.46 of 2200 F.
The impact of this modification was estimated to add another 30-100 F to this numbcr still leaving ample margin to the safety limit.
As a result of these discrepancies the licensee performed a justification for continued operation (JCO) documented as
. Safety Evaluation No. 272. The licensee concluded that continued operation was justified based on the large margins noted above until the SBLOCA could be reanalyzed. The-
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- reanalysis was scheduled for completion in January 1991.
Completion of this reanalysis and HRC review of the results will be tracked as an open item (50-282/90015-01; 50-306/90016-01).
The inspector reviewed the post-modification test for the tJnit 1 modification. No problems were identified with the scope, execution, or results of the test. The licensee had revised the reference pump curve (TDH vs. flow) as part of this modification. The manufacturers certified curve had been used f.s the reference for performance testing in the past. The new
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reference curve was based on the results of the original preoperational testing of the installed pumps. This is consistent with ASME Section XI guidance. Based on the new reference curve, one point on the curve as determined by the-post-modification test was in the alert range. The pumps are scheduled to be rebuilt during the next unit 1 outage.
Discussions with the system engineer indicated that the Unit 2 pumps exhibited the same problem and will be rebuilt during the next unit 2 outage.
One minor programmatic concern was identified. The formal modification team assignment form does not clearly identify the responsible design organization. Three Engineering Change Requests (ECR) had been issued during the installation of-this modification. Two of the ECR's listed Fluor-Daniel as the design organization and had been approved by them. The third ECR listed NSP as the design organization and had been approved by the system engineer. While there was no safety significance in this specific example, the design responsibility should be clearly identified for each modification. The licensee agreed to consider this issue.
No other concerns were identified.
(2) Modification 86Y700, " Accurate Feedwater Flow Signals" This modification replaced the Barton D/P gages used for feedwater flow determination with high accuracy transmitters to improve calorimetry.
The inspector reviewed the engineering package for this modification including the 10 CFR 50.59 evaluation.
No concerns were identified.
(3) Modification 87Y785, " Steam Generator Level Control" This modification revised the SG level control system to provide fully automatic control throughout the power range.
The modification used microprocessor-based instrumentation
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using signal validation of input signals.
The fundamental purpose of this modification was to increase the reliability
of= the feedwater (FW) control system and. reduce the~ number of reactor trips due to FW control malfunctions.
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The inspector focused his review on the adequacy of the
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licensee's assessment of potential new failure modes of the FW L
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control system, the 10 CFR 50.59 evaluation, post-modification b
testing, and operator training. Operator training was
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particularly pertinent in-this case because of the significant
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change in operator interface with the system.
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The inspector identified no significant concerns during the
-review.. Operator training was handled by simulating system
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behavior on the plant simulator well-in advance of the i
modification installation.
During post-modification testing
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and plant startup, differences in-the simulation model and
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-actual. plant performance were identified and were to be fed,
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back into the simulation model.
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(4)! Modification 89L114, " Vent-Valve on 122 Spent' Fuel Pool Heat
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-Exchanger"
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.This modification added a vent line to the:122 spent fuel pool; heat. exchanger. The modification was performed to all; o draining of.the heat exchanger. The inspector revie~wed'the.-
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110 CFR 50.59 analysis,-safety evaluation, ALARA evaluation, o
engineering work, and installation instructions for this -
modification.
A walkdown of-the' installed modification was_
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also performed. 'No concerns were' identified.:.
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> (5)- ModificationJ86L893, " Instrument Air' System Upgrade"-
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- This. modification added isolation valves, installed ' dewpoint j
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. stainless' steel for theninstrument air. system. The~ inspector--
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. reviewed the.10 CFR 50.59Eanalysis, safety evaluation,n
- engineering. work, and installation-instructions for this-F
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. modification. A walkdown offa portioniof the' installed
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modification was also performed.. No concerns:were' identified.
(6)_ Modificatio'n 89L119, Replace ' Circuit' Breakers FW lsolationi
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Valves MV32024 & MV23029"
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This: modification: replaced the;50: amp THEF breakers:used fori
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thefeedwaterisolationvalvemotor~ control: centers (MCC)i
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This modification was performed to improve breaker coordination between the -load brea ker to the motor valve and.the supply ~ breaker to the MCC. 1The ' inspector reviewed the 10 CFR 50.59 analysis, safety evaluation,
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n engineering work, dedication testing program, installation instructions, and insta11etion testing procedures for this modification. One of the installed breakers was also inspected.
No safety concerns were identified.
The replacement areakers were upgraded to safety-related by a connercial grade dedication process.
Comments related to the dedication process are presented in Paragraph 2 of this report.
The final installation test for the replacement breakers consisted of partially closing and reopening the isolation valves to verify direction of valve motor operation.
Although the test was performed while at power, there was no documentation of a 10 CFR 50.59 analysis which specifically covered the test. The licensee considered the test to be covered under the 10 CFR 50.59 analysis for the modification.
However, considering that the test was performed while at power, the inspector believed that a 10 CFR 50.59 analysis which specfically covered the test should have been done.
Because the licensee had reviewed the potential consequences of the test through their operations committee and had provided adequate measures during the test to ensure safety, there was no safety concern.
(7) Temporary Modifications The inspector reviewed the temporary modification program and four temporary modifications. The temporary modification program'was described in procedure SACD 6.5, " Temporary Modifications." 'The licensee also had a bypass program described in procedure SACD 3.9, Bypass Control." A bypass was defined as "any device which blocks a component out-of-service or which prevents it from performing its intended functions."
The bypass program was to be used only if the bypass would be installed for less_ than 30 days and no 10 CFR 50.59 evaluation was required. Otherwise, the temporary modification program was to'be used which required-the 10 CFR 50.59 evaluation. The determination that a 10 CFR 50.59 evaluation was not required was indicated by a checkmark on the bypass _ control form with no basis provided to support the conclusion.
The inspector had two concerns with the bypass program.
First, the lack of a documented basis for-concluding no 10 CFR 50.59 evaluation was required was not rigorous.
Secondly, step 6.3.2.c of SACD 3.9 was not clear on the need to use the temporary modification procedure if a 10 CFR 50.59 evaluation was required.
These issues were discussed with the licensee and they agreed to address them.
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Both prograns provided adequate control of installed temporary nodifications or bypasses including quarterly review by the on-site review committee for continued need and plans for removal.
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Conclusions Based on the results of this inspection, the inspectors reached the following conclusions:
The modification program was generally well implemented.
- The steam generator level control modification was well
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handled.
Provisions for operator training were strong.
The procedure governing " Bypasses" (5ACD-3.9) needs clarification to essure this program is not used when a 10 CFR 50.59 evaluation is required.
Also, the basis for determining that a 10 CFR 50.59 evaluation is not required should be documented.
Additional care should be taken to assure that the 10 CFR 50.59
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evaluation for a modification explicitly covers the post
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c modification testing when this testing is done while the system is operable.
The organization having design authority could be more clearly defined for each modification.
4.
Quality Verification Effectiveness (QVE)
The inspectors reviewed several audits and surveillances of the inodification program and one audit of the procurement program.
The audits of the modification program were effective'and in-depth. Two findings involved the processing of modification as alterations (no
. change in plant design or physical operating characteristics) and the-initiation of field work for a modification before final modification approval. Corrective actions were appropriate including a review of.all (
past alterations for actual modifications. Those found to represent design chenges were reprocessed as modifications to assure the proper degree of review and evaluation.
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!l The licensee performed an audit of procurement at Prairie Island during August 7-21, 1989.
Except for the area of CGI evaluation quality, the audit wds thorough and well done. Many improvements in the procurement, receipt inspection, and material control process were implemented as a result of the audit.
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Each of the weaknesses with CGI evaluations noted in Paragraph 2 were also found during the audit, in the area of CGI evaluations quality, the audit made specific recommendations for certain CGI evaluations and the recommendations were implemented.
However, the root cause analysis of the weaknesses in CGI evaluations was poor. Broader issues, such as training of preparers and reviewers of CGI evaluations and independent / supervisory review of CGI evaluations, were not addressed by the audit.
The inspector found little improvement in CGI evalutions prepared after the audit compared to those prepared shortly after the licensee's commercial grade dedication program was started. The corrective actions taken were insufficient to significantly improve the quality of CGI evaluations.
This weakness in corrective action appeared to be unique to the procurement program, at least in comparison to the effective actions taken relative to the modification program.
5.
Open items Open items are riiatters which have been discussed with the licensee which will be reviewed further by the inspectors and which involve some action on the part of the NRC or licensee or both.
An open item disclosed during the inspection is discussed in Paragraph 3.a.(1).
6.
Exit Interview The inspectors met with licensee representatives (denoted in Paragraph 1)
at the conclusion of the inspection on October 5,1990, and summarized the purpose, scope and findings of the inspection.
The licensee stated that the inspectors had no access to proprietary information.
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