ML20155B382
| ML20155B382 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 10/19/1998 |
| From: | Fredrickson P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20155B359 | List: |
| References | |
| 50-413-98-13, 50-414-98-13, NUDOCS 9810300134 | |
| Download: ML20155B382 (20) | |
See also: IR 05000413/1998013
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U.S. NUCLEAR REGULATORY COMMISSION
REGION II
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' Docket Nos: 50-413 and 50-414 l
License Nos: NPF-35 and NPF-52
Report Nos. 50-413/98-13 and 50-414/98-13
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Licensee: Duke Energy Corporation I
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Facility: Catawba Nuclear Station, Units 1 and 2
Location: 422 South Church Street
Charlotte. NC 28242
Dates: August 7 through September 15, 1998
Inspectors: S. Shaeffer, Senior Resident Inspector, McGuire (Lead
Inspector)
D. Roberts, Senior Resident Inspector. Catawba
Giles. Resident Inspector, Catawba
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Approved by: i _ eL~ m _ .
P. E. Fr'edrickson, thiff F "
m /' 9[7I
" 'Dath
Maintenance Branch
Division of Reactor Safety
Enclosure
9810300134 981019
PDR ADOCK 05000413
G PDR
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Report Details
Summary of Plant Status
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Unit 1 began the inspection period at approximately 100% power. On August 5.
1996, during the performance of on-line Unit 1 ice condenser Technical
Specifications (T.S ) required flow passage inspections, the licensee
identified evidence of flow blockage in Bay 5 and other bays. Based on a
licensee determination of Bay 5 being in a degraded condition, the licensee
declared the ice condenser inoperable on August 5 and entered a 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />
shutdown action statement. On August 7, the licensee initiated a downpower to <
place the unit in cold shutdown (MODE 5) to correct the ice blockage
L condition. After satisfactory repairs were completed, on August 31, 1998, the
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unit was restarted and ended the inspection period at approximately 100%
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Unit 2 operated at approximately 100% power during the entire period.
I. Maintenance
M1 Conduct of Maintenance
M1.1 General Comments (62700)
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During the inspection. the inspectors reviewed a variety of maintenance.
surveillance, and engineering activities associated with maintaining the
ice condenser and its associated sub-systems in an operable state.
Following observations of licensee activities associated with the
identification and resolution of problems identified with the Unit 1 ice
condenser system during the forced outage the inspectors concluded that
the appropriate attention was being applied to support the above
activities.
However, throughout the forced outage, a weakness was identified with
initial scoping of problems and thoroughness of licensee inspections
corcoleted during the outage related to flow channel blockage, foreign
material exclusion (FME) control, and material condition of ice
condenser baskets. Licensee management's failure to confirm the
thoroughness of contractor personnel to provide a proper scoping of
problen,s contributed to this weakness. After problems were identified
- by the NRC in each of these areas. licensee response to the problems
l were considered adequate.
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M1.2 Unit 1 Ice Bed Flow Passaae Dearadation Causino Forced Unit 1 Shutdown
a. Insoection Scooe (62707. 61726. 37551)
The inspector reviewed degraded ice condenser flow passages identified ,
in the Unit 1 ice condenser system during T.S. required surveillance i
testing by walkdowns of certain portions of the ice condenser system.
As-found conditions were evaluated with respect to the T.S. Updated
Final Safety Analysis Report (UFSAR) design basis documents, and
applicable licensee drawings and procedures. The degraded conditions
were also evaluated for initial root cause determinations and licensee
corrective actions.
b. Observations and Findinas
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b.1 Backaround
The inspector reviewed T S. compliance as related to T.S. 4.6.5.1.b.3.
which requires that at least once per nine months, a minimum of two flow
passages per each of the ice condenser's 24 bays be visually inspected
for blockage. With the frequency of the surveillance at nine months. l
two performances per operating cycle are typically required, one just l
prior to startup from a refueling outage and one at the nine-month !
interval, which has generally occurred with the unit at power. The
maximum allowable accumulation of frost or ice on flow passages through ,
the condenser is limited to 0.38 inch per T.S. The T.S. surveillance
activity has been performed in accordance with Procedure SM/A/8510/001.
Rev. 1. Inspection of Ice Condenser Flow Passages, with the selection of
flow passages for the T.S. surveillance conducted by the system engineer
using a random number generator.
On August 5, 1998 during the performance of on-line Unit 1 ice
condenser T.S.-required flow passage inspections. the licensee
identified evidence of flow blockage in Bay 5 and other bays. Per the
T.S., if one or more passages are found to have frost or ice in excess
of 0.38 inch. 20 additional flow passages from the same bay shall be
visually inspected. Upon the performance of additional inspections in
Bay 5. the licensee identified evidence of a significant number of flow
passages being blocked or partially blocked by ice and frost
accumulation. Based on the identification of the Bay 5 degraded
condition, the licensee declar ed the ice condenser inoperable on August
5. 1998 and entered a 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> shutdown action statement. Significant
flow channel blockage outside of Bay 5 was not evident. The licensee
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performed additional inspections and attempted to clean the identified
blocked flow channels in Bay 5. However, portions of the ice condenser
were considered inaccessible with the unit at power due to radiological
dose concerns. Therefore, the licensee determined that the degraded
condition could not be corrected within the T.S. limiting condition for
operation and a unit shutdown was completed to facilitate more complete
inspections and corrective actions.
b.2 Root Cause of Bay 5 Flow Blockaae
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L Upon shutdown, more detailed inspections of Bay 5 and adjacent bays
concluded that the significant ice blockage was limited to Bay 5 only. l
NRC and licensee review of previous outage activities concluded that the
ice flow passage blockage was the result of a leaking block-ice
processing machine which was utilized for the first time in July 1996 in i
Unit 1. The machine used borated water and ice to press preformed j
blocks for incorporation into the ice bed, and was developed exclusively
for the licensee to decrease future ice condenser servicing intervals.
The block ~ ice machine had been located over Bay 5. in the intermediate
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deck door area. for the duration of the Unit 1.1996 refueling outage l
and was noted to have had numerous leaks associated with the machine
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based on recollection of maintenance and engineering personnel involved
! with the outage. The machine was not used in Unit 2 or either of the
l McGuire ice condenser units. Leakage from the machine caused
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significant blockage of Bay 5 flow passages affecting more than half of
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the Bay 5 baskets, with the amount of blockage varying over the entire
l length of the baskets. There was also water seepage through th ice bed
- to the lower ice area. as evidenced by collection of ice on the lower l
l turning vanes and floor. l
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b.3 Secuence of Events Relatina to Flow Blockage
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The inspectors developed the following sequence of events for review of
l the licensee's actions related to the development of the Bay 5 flow
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blockage problem as follows:
Date Event Descriotion
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June 12, 1996 Unit 1 End of Cycle (EOC b9 refueling outage begins
June 25, 1996 Block-ice machine installed in Unit 1 ice condenser
July 1996 Block-ice machine leakage occurs
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i August 7, 1996 Block-ice machine removed from Unit 1 ice condenser I
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! August 8. 1996 Ice accumulation discovered in Bay 5. normal flow
channel cleaning for all bays initiated to support
final ice passage inspections. Problem identification ;
process (PIP) report not initiated i
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l August 12, 1996 System engineer acquired thermal drill from another
l utility to assist in cleaning Bay 5. Device was given ,
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to site ice condenser maintenance group l
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August 27, 1996 All flow channel cleaning in Bay 5 completed per l
maintenance. Engineering verification of as-left !
condition not conducted.
August 28. 1996 Nine-month interval T.S. surveillance 4.6.5.1.b.3
completed. Two random passages in Bay 5 were
considered satisfactory. No flow passage problems
identi fied.
October 4. 1996 Unit 1 starts up from EOC-9 refueling outage
April 28.1997 Nine-month interval on-line performance of T.S.
surveillance 4.6.5.1.b.3 completed. Two random
passages in Bay 5 were considered satisfactory. No
flow passage problems identified
November 28, 1997 Start of Unit 1 EOC-10 refueling outage l
December 1997 Identified 24 ice baskets stuck in Bay 5. attributed
to previous ice machine problem
December 21, 1997 Nine-month interval T.S. surveillance 4.6.5.1.b.3
completed at end of refueling outage. Two random
passages in Bay 5 were considered satisfactory. No
flow passage problems identified. 100 percent flow
channel inspection completed per licensee's program
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(no specific procedure).
January 4. 1998 Unit 1 starts up from EOC-10 refueling outage
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August 5. 1998 Nine-month interval on-line performance of T.S.
surveillance 4.6.5.1.b.3 completed. Problems
identified with Bay 5
August 7, 1998 Unit 1 shutdown to correct ice condenser deficiencies
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b.4 Corrective Actions for Identified Flow Blockaae
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l Throughout the forced shutdown, the licensee performed extensive
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cleaning in Bay 5 to remove or reduce the blockage from the flow passage ;
j* . areas. Not all of the blockage was able to be removed as a result of
l the Bay 5 leaking block-ice machine problem. Evaluation of the Bay 5 .
as-left condition is discussed in Section M1.2.b.7 below. All other l
l Unit 1 ice condenser bays flow passages were inspected by the licensee
i several times and adequately cleaned. The inspectors performed a
variety of final walkdowns to verify the as-left conditions. By the end
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of the outage, the licensee's ultimate sensitivity to cleaning flow
passages was considered' good.
The inspectors were also concerned with the use of a variety of
sharpened cleaning tools utilized in the ice removal process,
specifically, because of the potential for damage to the baskets or .
support lattice structures. After final flow channel cleaning was I
completed, the licensee and the inspectors performed inspections for
potential damage. Aside from minor damage, no operability concerns were
identified. This inspection was performed from both the top and bottom l
of the condenser: however, visibility past the first lattice support
structure was limited. The licensee was unable to perform full length '
b.isket inspections, in light of limited space outside the ice baskets
due to as-left blockage, further discussed in Section M1.2.b.7 below.
The licensee stated that more detailed inspection of the Bay 5 baskets
were planned to be conducted during the next scheduled refueling outage,
in that inspection accessability would improve due to the emptying of
numerous ice baskets in Bay 5 for servicing.
b.5 Reculatory issues for Flow Blockaae Deoradation
Based on the above sequence of events, review of available
! documentation and discussions with licensee personnel. the inspectors
evaluated the Bay 5 flow channel degradation for compliance with
i regulatory requirements. The licen:m is required by 10 CFR 50
Appendix B. Criterion XVI. to establish measures to ensure that
conditions adverse to quality are promptly identified and corrected. In
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! this case the licensee had several opportunities, including ice
. condenser servicing during a refueling outage and during the performance
of T.S. required surveillances. to promptly identify. evaluate and
implement corrective actions for the blocked flow passages which did not
meet known T.S. surveillance requirements. This failure to promptly
l identify and correct flow channel degradation is identified as Apparent
Violation EEI 50-413/98-13-01, Failure to Identify and Correct
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Significant Ice Condenser Flow Blockage. The inspector considered that
the engineering oversight and problem resolution for this degraded
condition in Bay five of the Unit 1 ice condenser was inadequate. This
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inadequacy led to a significant condition adverse to quality being left
unidentified and uncorrected for an approximate two year period.
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At the end of the inspection period, the licensee was in the process of
! completing a past operability review of the blocked ice condenser flow
l passages in Unit 1. Bay 5. Pending the licensee's completion of this ]
j review and NRC evaluation, this issue is identified as Unresolved Item
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! 50-413/98-13-02, Past Ice Condenser Flow Blockage Operability Review. 1
i b.6 Other Effects of Water Intrusion on Ice Bed Performance
In addition to the above issues, the inspectors reviewed the effect of
l the Bay 5 leaking ice machine problem on other aspects of the Unit 1 ice !
! condenser system including basket maximum allowed weight, stored ice l
l boron concentration, and any potential impact on T.S. requirements in j
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The inspectors discussed with the licensee, controls for the water used
in the block-ice machine and considered them adequate in providing
proper boron concentration to the ice machine. For this reason. no T.S.
minimum boron operability issue regarding the Bay 5 water intrusion was
identi fied. The inspectors also reviewed ice weights taken before and
l after the block-ice machine leakage and identified baskets which gained l
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a substantial amount of weight due to the addition of borated water.
For example. Bay 5 ice basket 7-4 indicated a net gain of approximately
250 pounds. The inspectors also noted that during the Unit 11997 i
refueling outage. 24 Bay 5 baskets were identified as being stuck and l
therefore unweighable. The licensee's sublimation prediction program
i allows for stuck baskets not to be weighed / serviced (i.e. unloaded,
inspected. refilled, and weighed) for one cycle of operation, if
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sublimation predictor values are acceptable. For this reason, system
, engineering determined that the 24 stuck baskets were operable after the
4 1997 refueling outage. The inspectors noted that evaluations were not
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performed for the baskets that were weighed and indicated a substantial
increase in mass. During a restart Plant Operations Review Committee
meeting, the licensee addressed the concern for potentially exceeding ;
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maximum weights per basket and concluded that no design limits were
exceeded.
The inspectors concluded that no known excessive ice weight operability
issue existed due to the Bay 5 problem and that the more critical
minimum ice mass requirements were met. The inspectors also concluded
that the abnormal identification of many stuck baskets in Bay 5 and the
. mass increase of other baskets during the 1997 Unit 1 refueling outage u
l were additional opportunities missed by engineering to identify and
correct the known condition adverse to quality, further discussed in
Section M1.2.b.5 above.
b7 Technical Soecification Flow Channel Interoretation
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During the licensee's corrective actions for the flow passage blockage
l in Bay 5. the inspectors noted that the licensee was cleaning the
blockage to a criteria which did not include the entire flow area
l between ice baskets. Instructions to maintenance personnel were to
apply the T.S. requirement of less than 0.38-inch of ice to the diamond
shaped areas formed by steel lattice support structures located between
i adjacent baskets. The inspectors estimated the flow areas outside of
l the diamond as approximately 50 percent of the total flow area. The
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licensee's interpretation of the terms " flow channel" or " flow passage"
l was defined via an internal engineering memorandum dated August 11.
j 1988. by engineer E. W. Fritz. With this interpretation. the licensee
j ir! tended to meet the intent of T.S. 4.6.5.1 by cleaning inside the
diamond area of the flow channel to the 0.38 inch criteria and leaving
l blockage outside of the diamond area. Flow passage cleaning outside the
! diamond area was to be performed to the extent practical: however.
substantial blockage could remain. The inspectors questioned the basis
for only applying the 0.38 inch T.S. criteria to the inside of the
diamond area, in that, the diamond area was approximately one half of
the total flow area and existed only at the lattice support structure
locations. No other basis documentation was provided by the licensee or
was identifled in either available design basis documents or the UFSAR
which could establish any basis for the licensee distinguishing between
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the inside or outside area of the diamond.
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Prior to unit restart. a telecon was conducted between NRC Headquarters
and Regional NRC management and the licensee to discuss their
interpretation of the flow channel definition. The licensee stated that
the intent of the T.S. requirement to maintain the ice build-up to less
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than 0.38 inch was to provide a quantifiable means of evaluating
blockage and not an operability limit. Based on a lack of specific
information defining flow channels as they relate to the Catawba T.S.,
the NRC acknowledged that it was appropriate for the licensee to apply
the 0.38 inch T.S. criteria to the inside of the diamond area, until
further information was available to more completely evaluate the
licensee's interpretation. The inspectors noted that with the exception
of areas outside the diamond in Bay 5. inspections in all other bays
identified no substantial ice buildup either inside or outside the flow '
channel diamond areas. Prior to restart, the licensee performed both !
l substantial cleaning of the Bay 5 areas outside the diamond as well as
complete cleaning of inside the diamond areas.
On September 4, 1998, the NRC received and reviewed information relative
to the definition of flow channel areas for the Tennessee Valley
Authority's (TVA) Watts Bar ice condenser facility. The inspectors
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reviewed the document, dated August 31. 1998. from the Westinghouse l
Electric Company to TVA and concluded that the Catawba interpretation of l
flow channel was not conservative. In light of this new information. l
the NRC requested that Duke Energy obtain and review the information to I
determine if their original flow passage definition for T.S.
surveillance activities was valid. The licensee determined that the
full area definition of a flow channel (provided in the Westinghouse
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document) placed the areas outside the diamond on Bay 5 in a degraded
condition which needed to be evaluated for operability concerns. The
Westinghouse document provided a means by which operability could be
! shown via an analytic analysis of the ice condenser by segmentized flow
l channel analysis. Specifically, with the ice condenser separated into
six segments, if summation of all the known flow blockage in a given
segment was less than 15 percent, each segment and hence the ice
condenser system could be considered operable. The licensee performed
additional inspections of the as-left blockage, performed the segment
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analysis, and concluded that the ice condenser was operable with areas
outside the diamond in Bay 5 having residual blockage. The licensee
l conservatively estimated that the segment including Bay 5 had
approximately 9 percent total blockage.
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l These findings were discussed during a subsequent NRC/ licensee telecon
l on September 11. 1998. The NRC concluded that no current operability
issue existed. The licensee informed the NRC that they planned to
pursue changes to this and other ice condenser TSs to eliminate the need
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for interpretations and improve ice condenser surveillance program
reliability.
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l. c. Conclusions for Flow Blockaoe Problem
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l An apparent violation of 10 CFR Part 50, Appendix B, Criterion XVI was q
l identified for failure to identify and correct significant ice condenser '
flow blockage. The identification of many stuck baskets in Bay 5 and the ;
mass increase of other baskets during the 1997 Unit 1 refueling outage i
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were additional opportunities to identify and correct the significant )
I condition adverse to quality. Licensee evaluations regarding potential ,
adverse impact of the leaking block-ice machine on critical minimum ice l
mass requirements were adequate.
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Immediate licensee corrective actions for the flow channel problem. l
including a forced unit shutdown and extensive cleaning of the affected j
area was considered adequate to support restart of the unit.
Based en the receipt of new design basis information. previous licensee
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interpretations regarding ice condenser flow passage areas were
determined to be non-conservative. An unresolved item was identified
concerning past ice condenser flow blockage operability.
M1.3 Foreion Material Identified in Unit 1 Ice Condenser
a. Insoection Scone (62700. 62707. 61726. 37551)
The inspectors reviewed N.{C and licensee identification of foreign
material in the Unit 1 ice condenser and requirements for maintaining
areas inside the containment free of foreign material which could
adversely impact the containment sump. The inspectors walked down
applicable systems during this review.
b. Observations and Findinos
T.S. 4.5.2.c requires. in part. that each emergency core cooling system
(ECCS) subsystem shall be demonstrated operable by a visual inspection
which verifies that no loose debris is present in the containment which
l could be transported to the containment sump. The visual inspection
shall be performed for all accessible areas of the containment prior to
establi-hing containment integrity. Implementation of this T.S.
surveillance is accomplished, in part by. PT/0/A/4200/002, Containment
Cleanliness Inspection. In addition. Duke Energy Nuclear Site Directive
104.7. Standards for Foreign Materia Exclusion. provides a program to
L prevent the instruction of foreign material into open systems or
components.
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l Prior to the Unit 1 shutdown and throughout the outage the licensee
i identified evidence of inadequate FME control in the Unit 1 ice
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condenser. Although full accounting of the foreign material was not
complete at the end of the inspection period, the license estimated the
total debris to be approximately 30 gallons. Types of debris identified
included ice loading bags. tape and rope sections, gloves, shoe covers,
tie wraps and various metal parts. Of particular concern were the large
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plastic ice loading bags found in the condenser, which had been
previously used during ice condenser servicing. These bags
(approximately 4.5 bags found) are one foot diameter tubular plastic. 55
feet in length. They are normally inflated in the ice channels to help ,
retain the ice in the ice basket while ice filling is in progress. In l
- the early 1990's, the licensee changed the color of the bags used from I
l clear to orange to provide for better visibility. The majority of the
bags recently discovered were the previously used clear type. The bags
may have posed a particular threat to the operability of the ECCS sump 1
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l af ter a loss of coolant accident. ice condenser blowdown, and swap-over
l to the ECCS sump recirculation. The potential transport pathway for
this and other foreign material in the ice condenser would be ejection
- through the top of the condenser, initial transport to lower containment
! through the refueling drains or via the ice condenser drains, and then
I final transport through the polar crane wall penetrations to the ECCS
sump location.
Prior to Unit I restart, the licensee identified a number of items which
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! could not be easily removed from the ice condenser. These items. l
l including sections of rope and tape, tie wraps, and several whole pieces l
of the plastic ice loading bags previously described, were evaluated via
l PIP 1-C-98-2911 to be left in % e condenser until the next refueling
i outage. The inspectors reviewed the qualitative analysis which used
several assumptions in determining the ultimate ability of the material
to transport to the sump, and considered it generally conservative.
Detailed NRC inspections were conducted prior to unit restart for FME
concerns. Although final FME quality was the result of an iterative
l process, the as-left condition of the condenser was considered adequate.
l Since the most opportune time for inspecting for FME inside ice baskets
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is after the ice mass has been vibrated out during refueling outage
! scheduled servicing. the licensee planned to conduct more detailed
inspections of the interior of emptied ice baskets during the next
refueling outage.
The inspectors concluded that the above FME control requirements were
not adequately implemented to meet the requirement of T.S. 4.5.2.c as
evidenced by the substantial amount of foreign material identified in
the. Unit 1 ice condenser system. This failure to maintain ice condenser
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FME control is identified as Apparent Violation EEI 50-413/98-13-03. l
Inadequate-Ice Condenser Debris Visual Inspection. I
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At the end of the inspection period, the licensee was still evaluating
the potential effect of the entire amount of foreign material identified '
on the Unit 1 ECCS sump. Pending licensee completion of this review and
NRC evaluation. this issue is identified as Unresolved Item 413/98-13- 1
04. Past Ice Condenser Foreign Material Effect on ECCS Sump Operability
Review.
c. Conclusions
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An apparent violation of T.S. 4.5.2.c was identified for failure to
conduct adequate visual debris inspections in the Unit 1 containment.
An unresolved item was identified concerning foreign material effects on i
the Unit 1 containment ECCS sump. l
The licensee's efforts to exclude foreign material from the ice
condenser during previous outages had not been adequate as evidenced by l
l the amount of debris found during this outage and the evaluation i
discussed above. At the end of the inspection. licensee's attention to
i the area of foreign material exclusion in the ice condenser had 4
improved.
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M1.4 Dented / Buckled Ice Baskets
a. Insoection Scooe (62707. 61726. 37551)
The inspector reviewed degraded ice basket material conditions
identified in the Unit 1 ice condenser system identified during a forced
Unit 1 shutdown. As-found conditions were evaluated with respect to the
T.S.. UFSAR design basis documents, and applicable licensee drawings
and procedures. Licensee corrective actions taken to correct the
l conditions were reviewed prior to unit restart.
I b. Observations and Findinas
During the Unit 1 shutdown, approximately 58 basket dents were
i identified, repaired and/or evaluated by the licensee. Denting or
buckling of baskets could potentially affect the ability of the ice
basket to sustain as-designed loading conditions. The licensee's
previous allowable dent size for denting was one-inch deep and 10 inches
in length. During the unit shutdown, the licensee received and
incorporated more restrictive criteria from the vendor of 0.75-inch deep
and six-inch length. The licensee repaired the identified dents with a
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special tool developed to pull out dented baskets. The licensee also
reviewed specific dents with the vendor, via pictures, to assure as-left
configurations were acceptable. The majority of the identified dents
were located on the bottom six-feet of the ice baskets. Late in the
outage, one significant buckle was identified by the inspectors and
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adequately repaired by the licensee before unit restart. The licensee
postulated that the majority of the dents were likely the result of
original installation practices. The inspectors considered that the
licensee had numerous opportunities to identify and correct the
identified dented baskets, such as during flow passage inspections. I
F weighing activities, or lower ice condenser bay cleaning. The licensee l
is required by 10 CFR Part 50 Appendix B. Criterion XVI to establish
measures to ensure that conditions adverse to quality are promptly
identified and corrected. This failure to promptly identify and correct
basket material condition problems is identified as Apparent Violation I
EEI 50-413/98-13-05, Failure to Identify and Correct Ice Basket
Deformation.
At the end of the inspection period, the licensee had not yet completed
a past operability review for the potential inoperability of the ice
condenser due to the identified dented baskets. Pending license
completion of this review and NRC evaluation, this issue is identified
as Unresolved Item 50-413/98-13-06. Past Ice Condenser Dented Basket
Operability Review.
c. Conclusions
An apparent violation of 10 CFR Part 50 Appendix B, Criterion XVI was
identified for failure to promptly identify and correct ice condenser
basket material condition problems. Corrective actions taken for the ice
condenser basket denting problems was adequate to support restart of the
unit. An unresolved item was identified concerning past operability for
denting identified on ice condenser baskets.
M1.5 Deck Door Boltina and Hardware Issues
a. Insoection Scooe (62707. 37551)
The inspectors reviewed the condition and installation of the Unit 1 ice
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condenser intermediate doors and top deck blankets. Areas reviewed
included the bolting requirements for the intermediate deck door frames
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and the structural steel supports as described in drawings CNM 1201.17-
i. 0498. -0080. and -0488. The installation requirements for the top deck
j blankets as detailed on drawing CNM 1201.17-0512 were also reviewed.
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b. Observations and Findinas l
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The design of the intermediate deck doors (per bay) consists of a door l
frame unit housing eight intermediate deck doors. The door frames are l
attached to the structural steel I-beams located over the ice baskets. !
- During the outage. the licensee identified a number of problems
associated with the door frame fasteners including missing bolts, nuts,
washers, and bushings, in addition to inadequate torquing of some of ;
i these components. In addition, one structural T-bar beam assembly to I
l which the door frames are attached, had missing bolts. The licensee I
took corrective actions to address these concerns prior to unit restart. l
l Toward the end of the outage. the inspectors also identified inadequate l
l washer overlap on a number of the fasteners due to a variation in door
l frame alignment slot size. This problem resulted in a number of the
l fasteners not engaging the door frames at all. Upon identification to
l the licensee, the problem was corrected via the installation of larger
l Washers. The inspectors noted that this specific problem had been
l previously identified by the licensee at the McGuire ice condenser
j facility and corrected at that facility by a modification. l
l l
l Also, during the outage, several material issues were identified with !
'
the top deck blankets and associated hardware. These problems included
( several small perforations on four of the blankets. As the licensee did
not have an approved repair method, the affected blankets were replaced
with new vendor blankets in accordance with approved procedures. Other
problems were identified with the condition of blanket hardware which
were contrary to the installation requirements detailed on drawing CNM
1201.17-0512. specifically three missing vapor tape retaining clips.
The licensee corrected the known material condition issues associated
l with the top deck blankets and hardware in an adequate manner prior to
l
'
Unit 1 restart. The inspectors concluded that replacement of the torn
blankets was a conservative action.
The licensee is required by 10 CFR 50. Appendix B. Criterion V to
accomplish activities affecting quality in accordance with documented
drawings. The failure to ensure that the intermediate deck door and
structural bolting requirements were implemented per drawings CNM
1201.17-0498. -0080. and -0488. and the failure to install the vapor
barrier retaining clips are identified as two examples of Apparent
- Violation EEI 413/98-13-07, Failure to Properly Install Ice Condenser l
,
Deck Door Bolting and Hardware.
1
.
__ . . . ._
,
.
14
c. Conclusions
An apparent violation of 10 CFR Part 50. Appendix B. Criterion V was
identified for failure to accomplish activities affecting quality in
accordance with documented drawings, Corrective actions taken for the
ice condenser intermediate deck door problems and top deck blanket
issues were adequate to support restart of the unit.
M1.6 Ice Bed Technical Soecification Chemical Samolina
'
a. Insoection Scooe (61726. 37551)
Technical Specification 4.6.5.1.b requires, in part that the ice
condenser shall be determined operable at least once per 9 months by
chemical analysis which verifies that at least nine representative
-
samples of stored ice have a boron concentration of at least 1800 ppm as
sodium tetra borate and a pH of 9.0 to 9.5 at 20 degrees C. The
inspectors reviewed the history of how the licensee performed the
sampling and compliance with T.S.'s via Procedure OP/1/A/6200/027
Operating Procedure for Sampling Local Primary Sample Points.
b. Observations and Findinas
i
Previous to this inspection, the licensee had performed the sampling by
taking nine representative samples across the ice bed, mixing equal
amounts from the samples together, and then performing one analysis of
the sample to apply the T.S. criteria. During the inspection period. l
the inspectors questioned this practice as potentially being non-
conservative and not providing sample data to identify a potential
condition adverse to quality (i.e., specific high or low samples). The
licensee addressed the issue via PIP 1-C-98-3004 which concluded that
this mixing technique met the intent of the T.S. requirement. However,
the licensee did consider that they would enhance their sampling
technique to evaluate each of the nine samples independently to attain l
additional assurance of ice bed chemical integrity.
During the first-time performance of the expanded T.S. chemical
surveillance, one of the nine samples taken indicated a significantly
lower ppm of 1345 (basket 2-7-7). The licensee did not consider that
the one low sample resulted in a failed T.S. surveillance, in that, the
numerical average of all nine samples.1993 ppm was above the T.S.
lower limit of 1800 ppm. The Catawba chemistry group then utilized a
McGuire sampling technique which drew the sample from further in the ice
bed, away from the affects of sublimation or clear ice build-up, and
resampled a number of baskets. The second sample of the original low
I
)
.
15
basket of 1345 ppm wr found to be approximately 1760 ppm still below
, the T.S. limit. In addition, one additional low basket of 1642 ppm and
one high basket exceeding the upper limit per the accident analysis of
2350 were identified. Although several individual samples were not
within the T.S. or the accident analysis limit, the licensee considered
l
-
that averaging the data from the samples to show compliance with the
T.S. and other limits, met the intent of the T.S. .
l
l
The licensee's approach to meeting the intent of T.S. 4.6.5.1.b.1 was
'
discussed during a telecon between NRC headquarters and regional
management, and the licensee. Based on the discussions. NRC management
! determined that the intent of the specific T.S. in this area was not
l sufficiently specific and warranted improvement to more clearly address
T.S. intent in the actual specification. The licensee did perform
limited additional sampling to gain added assurance that no immediate
operability concern existed. As previously discussed in Section
M1.2.b.7, the licensee was planning to pursue clarifying changes to the
T.S.
c. Conclusions ,
i'
The stored ice chemical sampling T.S. was not sufficiently specific and
warranted improvement to more clearly address T.S. intent in the actual
specification. No immediate operability concerns were identified in i
this area. l
l
l M1.7 Restart Insoections l
l
After corrective actions were implemented by the licensee for the I
identified Unit 1 material condition issues, the inspectors performed
final walkdowns of the ice condenser. The final inspections focused on
foreign material identification, flow channel integrity, and compliance l
with known T.S. and design requirements. Nonconforming items were
, identified to the licensee and promptly corrected. The inspectors
concluded that final material condition of the Unit 1 ice condenser was
adequate to support operability of the ice condenser system. The
inspectors also reviewed all applicable ice condenser T.S. surveillances
prior to restart and concluded that the licensee had appropriately
identified and implemented those warranted to be accomplished based on
the extensive work activities during the forced outage.
i
-m _ . . _ . -. _ _ _._ _ ._ _._ __ _. _ _ _ _ . . _ . _ _ . _ . _ _ _ _ _ _ _ . . _
k
,
!
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16
4
!
< II. Enaineerino ]
1E2 Engineering Support of Facilities and Equipment J
l
E2.1 Unaooroved Plant Modifications '
a. Insoection Scooe (37551)
!
'
NRC walkdown reviews were condu ted in all areas of the Unit 1 ice !
condenser, comparing the as-built configuration to the design basis.
l
b. Observations and Findinos )
In general, the inspectors identified that the ice condenser system was j
being maintained and operated in accordance with the design basis and
- -
changes were being accomplished in accordance with approved procedures.
However, the following three exceptions were noted and considered-as
unapproved modifications.
The first example was identified during the walkdown of the upper plenum
around the intermediate deck doors. Specifically, the inspectors
identified a substantial. amount of wire mesh installed in the crevice
behind the ice condenser air handling units (AHU) on both the
-
containment and annulus side of the ice condenser. The purpose of the
mesh was to prevent tools, debris, and other foreign material from
' falling behind the AHus in locations where retrieval would be difficult.
The inspectors determined that the installation of the mesh, which was 1
estimated to have been installed in the mid-1980s~ was not in accordance l
with existing design control measures as required by 10 CFR 50.
Appendix B. Criterion III. The inspectors informed the licensee of the ;
wire and it was' removed from both units by the end'of the inspection l
4
period. This failure to maintain design control of ice condenser system
modifications is identified as the first example of Apparent Violation
EEI 50-413. 414/98-13-08. Inadequate Design Control.
'
'
The second example of EEI 50-413, 414/98-13-08 concerned the unapproved
original construction installation of a one-by-two-inch black foam
(Armaflex) strip along the entire length of the ice condenser aside the
top deck blanket. The. purpose of the strip was to fill a gap created by
- the top deck vapor barrier curtain located at the containment liner and
the edge of the top deck blankets. Installation of the material was not
in accordance with established procedures or arawings or as part of an
approved plant modification. This problem was also identified in
Unit 2. The licensee performed a 10 CFR 50.59 safety review of the
. - . . . - . . --
- - . . .--.
- .
l
17
impact of the strip and determined that it could remain in-place in both
units after minor repairs were accomplished.
l The third example of EEI 413, 414/98-13-08 concerned the unapproved
l installation of fiberglass tape used on the top deck blankets to provide
l additional vapor barrier protection outside of established design
, control measures. The plant design allowed for use of the subject tape
l in certain locations; however, the tape application in the allowed
configurations called for the tape to be mechanically restrained to
prevent the tape from dislodging during ice condenser ejection.
Unrestrained tape could potentially become dislodged and could present a
threat to the refueling drain and containment ECCS sump function. The
inspectors identified several areas where tape was applied outside of
l the plant design. These areas were on the top deck blankets between
! bays and in a circumferential configuration on the blankets (containment
liner side). The subject tape was removed from Unit 1. This issue was
l also identified on Unit 2 and evaluated for operability to remain
installed until the next Unit 2 refueling outage. At the end of the
inspection period, the licensee was evaluating the impact of the above
l and other foreign material items with respect to past ECCS sump
l operability, as discussed in Section M1.3.
c. Conclusions
l An apparent violation was identified concerning inadequate design
control measures within the Unit 1 and 2 ice condenser systems.
Corrective actions taken for the identified concerns were adequate to
l support restart of Unit 1 and continued operation of Unit 2,
l
l III. Manaaement Meetinas
l
l
X1 Exit Meeting Summary
The inspectors presented the inspection results to members of licensee
l -management at the conclusion of the inspection on September 16. 1998. A
subsequent re-exit was conducted by telephone on October 19, 1998 to discuss
the specific apparent violations in the report. The licensee acknowledged the
findings presented. Although proprietary information was identified and
reviewed during the inspection, none of this information was utilized for this
report.
l
!
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18
PARTIAL LIST OF PERSONS CONTACTED
1
i Licensee
S. Bradshaw, Safety Assurance Manager
R. Glover, Operations Superintendent
P. Herran, Engineering Manager
R. Jones. Station Manager
M. Kitlan, Regulatory Compliance Manager
G. Peterson. Catawba Site Vice-President
D. Rogers.. Maintenance Manager
INSPECTION PROCEDURES USED
IP 62700: Maintenance Implementation
IP 62707: Maintenance Observations
IP 61726: Surveillance Observations
IP 37551: Onsite Engineering
ITEMS OPENED
OPENED
50-413/98-13-01 EEI Failure to Identify and Correct Significant Ice
Condenser Flow Blockage (Section M1.2)
50-413/98-13-02 URI Past Ice Condenser Flow Blockage Operability
Review (Section M1.2)
50-413/98-13-03 EEI Inadequate Ice Condenser Debris Visual l
Inspection (Section M1.3) l
l
50-413/98-13-04 URI Past Ice Condenser Foreign Material Effect on ;
ECCS Sump Operability Review (Section M1.3)
50-413/98-13-05 EEI Failure to Identify and Correct Ice Basket
Deformation (Section M1.4)
50-413/98-13-06 URI Past Ice Condenser Dented Basket Operability
Review (Section M1.4)
50-413, 414/98-13-07 EEI Failure to Properly Install Ice Condenser Deck
Door Bolting and Hardware (Section M1.5)
50-413. 414/98-13-08 EEI Inadequate Design Control (Section E2.1)
.- -- . = .
.
. I
19
l
l
l. LIST OF ACRONYMS USED
l
AHU -
Air Handling Unit ,
CFR -
Code of Federal Regulations I
DBA -
Design Basis Accident )
l ECCS -
i
! EEI -
Escalated Enforcement Item i
EOC -
End of Operating Cycle i
FME -
l
'
... I F I --
. Inspector Follow-up Item l
IR -
Inspection Report I
LCO -
Limiting Condition for Operation I
'
LOCA -
Loss of Coolant Accident
NRC -
Nuclear Regulatory Commission
'
NRR -
NRC Office of Nuclear Reactor Regulation
NSD -
Nuclear Site Directive
OE -
Office of Enforcement
POR -
Public Document Room
PIP -
Problem Investigation Process
PM -
Preventive Maintenance
l
PPM -
Parts Per Million l
PT -
Periodic Testing
RO -
Reactor Operator
T.S. -
Technical Specifications
UFSAR -
Updated Final Safety Analysis
WO -
Work Order
l
l
l
,
,