ML17309A762
| ML17309A762 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 11/18/1994 |
| From: | FLORIDA POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML17309A761 | List: |
| References | |
| JPN-PSL-SEMS-94, JPN-PSL-SEMS-94-026, JPN-PSL-SEMS-94-26, NUDOCS 9411300201 | |
| Download: ML17309A762 (24) | |
Text
JPN-PSL-SEMS94-026 REVZSZON 1 St. Lucie Unit 1 PAGE 1 of 17 Docket No. 50-335 NRC Bulletin 89-01 Westinghouse Steam Generator Tube Mechanical Plu s FLORIDA POWER & LIGHT CO ENGZNEERING EVALUATION OF INSTALLED WESTINGHOUSE STEAM GENERATOR TUBE PLUGS ST LUCZE NUCLEAR PLANT UNIT 1 JPN-PSL-SEMS-94-026 REVISION 1 SAFETY RELATED 9411300201 941125 PDR ADOCK 05000335 9 PDR
JPN-PSL SEMS-94 026 REVXSION 1 PAGE 2 of 17 REVIEW AND APPROVAL RECORD PLANT ST. LUCIE UNIT TITLE ENGINEERING EVALUATION OF INSTALLED WESTINGHOUSE STEAM GENERATOR TUBE PLUGS LEAD DISCIPLINE MECHANICAL ENGINEERING ORGANIZATION PSL SITE ENGINEERING GROUP REVIEW/APPROVAL:
INTERFACE TYPE GROUP PREPARED VERIFIED APPROVEO FPL APPROVED*
INPUT REVIELI H/A MECH N/A ELECT H/A IEC H/A CIVIL N/A HUC H/A ESI H/A NUCFUEL H/A N/A
- For Contractor Evals As Determined By Projects ** Review Interface As A Min On All IOCFR50.59 Evals and PLAs PPL PROJECTS APPROVAL: DATE:
OTHER IHTERFACES JPH Form 24, Rev. 9/92
ZPN-P SL-S EMS-9 4 02 6 REVISION 1 PAGE 3 of 17 TABLE OF CONTENTS DESCRIPTION PAGE 1.0 ABSTRACT/
SUMMARY
4 2.0 PURPOSE AND SCOPE 6
3.0 BACKGROUND
. . . . . . . . ~ ~ ~ ~ 6 4.0 EVALUATION . . . . - . - . . ~ ~ ~ 11
5.0 CONCLUSION
AND REQUIRED ACTIONS 15 6.0 VERIFICATION
SUMMARY
16
7.0 REFERENCES
. . . . . . . . ~ ~ 16 FIGURE 1: INSTALLED WESTINGHOUSE MECHANICAL TUBE PLUG 17 ATTACHMENTS: No. of Pa es St. Lucie Action Report STAR ¹ 1-94110347, dated 11/5/94. (Rev. 0)
Memo JPN-CSI-94-506, Boyers to Craig, "PSL-1 Steam Generator Plugs Identified Leakage STAR ¹ 1-94110347", dated 11/11/94 (Rev. 0)
Westinghouse letter 94-JB-GL-5386, "Evaluatio'n 8 of Reported Leaking Mechanical Plugs at St. Lucie Unit 1<<, dated 11/11/94. (Rev. 0)
Memo, Frechette to Craig, "Status of PSL-1 Steam Generator Tube Leaks", dated 11/7/94 (Rev. 0)
Westinghouse letter 94-JB-GL-5401, "On Efforts to Remove a Westinghouse Mechanical Plug at St. Lucie Unit", dated 11/18/94. (Rev. 1)
t JPN-PSL SEMS-94 026 REVISION 1 PAGE 4 of 17 ABSTRACT
SUMMARY
Visual inspection of the St. Lucie Unit 1 steam generators during the end of cycle 12 refueling outage identified a total of seventeen (17) leaking tube Plugs. STAR P 1-94110347 requested an evaluation of the leaking plugs.
Two of the plugs are ABB/CE welded tube plugs in the "A<< hot leg channel head, and were observed to have heavy boron accumulation. The leaking welded tube plugs will be replaced.
There are no generic issues with this plug design.
The other fifteen leaking plugs are Westinghouse mechanical tube plugs in the hot leg channel heads; these plugs will be replaced. NRC Bulletin 89-01 "Failure of Westinghouse Steam Generator Tube Mechanical Plugs" identified a limited service life for this type of plug material/design.
The purpose of this evaluation was to determine the significance of the leaking Westinghouse tube plugs and provide a recommendation for the remaining plugs. There are a total of 506 Westinghouse tube plugs in both hot leg channel heads, fabricated from a single heat (NX2387) of Inconel 600.
Based on the Westinghouse algorithm (WCAP-12244 Rev. 3), the recommended repair date for these plugs was 2004.
Westinghouse reviewed the St. Lucie data and concluded that plug leakage was most likely due to an axial or limited circumferential crack above the plug expander (see Figure 1).
As a result, they revised the algorithm which predicts when a plug top release from PWSCC (North Anna event) will occur.
For St. Lucie, the predicted time remaining from the current outage to plug top release is 3.0 effective full powers years (EFPY), or 2.25 fuel cycles. There have been no plug top release occurrences earlier than predicted by the Westinghouse algorithm.
The bases for continued safe plant operation with the remaining plugs remain valid for the following. reasons:
- 1) A plug top release event is unlikely to occur because cracking above the expander is expected to be axial or limited circumferential orientation.
- 2) If a plug top release event does occur the plug top would not perforate the tube (row 5 or greater).
- 3) The majority of tubes with Westinghouse mechanical plugs were removed from service for preventative reasons.
Therefore, a plug top release is not expected to cause a tube rupture.
JPN-PSL-SEMS94-026 REVISION 1 PAGE 5 of 17
- 4) Circumferential cracking is expected to occur below the expander prior to the occurrence of cracking above the expander. Cracking below the expander will not result in a plug top release.
- 5) It is unlikely that cracking below the expander will result in the bottom portion of the plug becoming a loose part. The physical interference of the plug skirt and lower sealing lands with the inside diameter of the tube retains the bottom portion of the plug in the tube. Also, Westinghouse reported that there have been no known occurrences of the bottom portion of the plug becoming a loose part.
Should a portion of the plug become a loose part, it. is unlikely that it would migrate out of the steam generator.
The loose parts monitoring sensors on the steam generator should provide indication.
The following remedial action is recommended this outage:
- 1) Replace the leaking Westinghouse plugs, and;
- 2) Replace two Westinghouse plugs in tube row 4. This is a preventative measure because dynamic tests for tube perforation did not bound rows 1 to 4.
If a suitable artifact Westinghouse plugs, these is available from . the.. removed should be examined to characterize the PWSCC to provide data for future reference.
J'PN-PSL-SEMS-94-026 REVISION 1 PAGE 6 of 17 2 ' PURPOSE AND SCOPE Visual inspection of the St. Lucie Unit 1 steam generators during the end of cycle 12 refueling outage identified a total of seventeen (17) leaking tube plugs. STAR ¹ 1-94110347 requested an evaluation of the leaking plugs.
Two of the plugs are ABB/CE welded tube plugs in the "A" hot leg channel head, and were observed to have heavy boron accumulation. In accordance with ASME B&PV code Section XI/
the leaking welded tube plugs will be replaced. There are no generic concerns regarding welded tube plugs, therefore no further evaluation is necessary.
The other fifteen leaking plugs are Westinghouse mechanical tube plugs in the hot leg channel heads; these plugs will be replaced. NRC Bulletin 89-01 "Failure of Westinghouse Steam Generator Tube Mechanical Plugs" identified that there was a limited service life for this type of plug. Figure 1 illustrates a schematic of the installed plug.
The purpose of this evaluation is to determine the significance of the leaking Westinghouse tube plugs and provide a recommendation for the remaining plugs. There are total of 506 Westinghouse tube plugs in both hot leg channel heads, fabric'ated from a single heat (NX2387) of Inconel 600, which were installed in 1984. Per the NRC Bulletin 89-01 and Reference 4b, repair was recommended for these plugs by 2004.
The cold leg plugs made from heat 2387 have a predicted repair date of 2159 and are therefore bounded by the hot leg plugs.
It is noted that in the 1B steam no primary to secondary leakage was detected generator during the last operating cycle (Attachment 4). The 1A steam generator continued to exhibit a very small amount of leakage that has been detected since 1986.
3 ' BACKGROUND 3 1 DESIGN OF THE STEAM GENERATOR TUBES/PLUGS The inservice inspection of the steam generator is governed by the Technical Specification Surveillance Requirements of Section 4.4.5, Steam Generators (Reference 2). Any tube which does not satisfy the acceptance criteria is plugged. The tube plugs and their installation are designed to maintain the primary to secondary boundary of the steam generators under all operating, transient or test conditions (Reference 1 section 5.5.1). The mechanical tube plugs are qualified through testing under conditions which meet or exceed the steam generator design conditions (Reference 3).
t JPN-PSL-SEMS-94-026 REVISION 1 PAGE 7 of 17 3 ' WESTINGHOUSE MECHANICAL TUBE PLUG PERFORMANCE The majority of Westinghouse tube plugs from heat 2387 were installed at St. Lucie Unit 1 as a preventative measure due to concerns related to possible corrosion from steam blanketing in tube rows 7 to 11. That is, there are no known through wall cracks of these plugged steam generator tubes, and most had no known degradation when they were plugged.
The root cause of the steam generator tube rupture event at North Anna Unit 1 was a plug top release resulting from circumferentially oriented Primary Water Stress Corrosion Cracking (PWSCC). NRC IE Bulletin 89-01, "Failure of Westinghouse Steam Generator Tube Mechanical Plugs" identified certain heats of thermally treated Inconel 600 plugs, and required plants to take remedial and long term action. Remedial action was not required for material heat 2387.
Remedial and long term action was based on a Westinghouse algorithm which predicts when a plug top release due to PWSCC would occur. Based on additional field data, the algorithm was revised, which resulted in two supplements to the NRC Bulletin.
FPL took remedial action via PC/M 251-189 by replacing the plugs fabricated from the suspect material heats installed at St. Lucie Unit 1 (i.e. NX3513). St. Lucie Unit 2 does not have any Westinghouse mechanical tube plugs (Reference 6). FPL has responded to the Bulletin's long term action plan (Reference 7). ~ ~
3 ' END OF CYCLE 12 INSPECTION RESULTS Although not required by Technical Specifications, the Components, Supports and Inspection (CSI) department of Nuclear Engineering visually inspected all tube plugs installed in the steam generators during the end of cycle 12 refueling outage.
CSI identified fifteen (15) Westinghouse mechanical tube plugs in the steam generator hot leg channel heads which were leaking water from the inside bore. Mechanical probing verified the top of the tube plug was intact.
e JPN-PSL-SEMS-94-026 REVISION 1 PAGE 8 of 17 3.4 WESTINGHOUSE EVALUATION AND PLUG REMOVAL EFFORTS The latest Westinghouse report of steam generator tube plug integrity (Re ference 4b) provides a recommended repair date based on operating time to preclude a plug top release. The recommended plug repair date was 2004 for heat 2387 plugs in the hot leg channel heads.
Westinghouse provided an evaluation (Attachment 3) based on the CSI visual inspection results. Westinghouse also provided a preliminary letter (Attachment 5) of their attempt to remove intact one of the St. Lucie leaking plugs this outage. The letter and evaluation are summarized below.
3.4.1 EFFORTS TO REMOVE A WESTINGHOUSE PLUG AT ST. LUCIE An attempt was made to remove one of the leaking plugs.
The first step to remove the plug requires applying a force to the bottom portion of the plug (see Figure 1).
A hydraulic system is used to develop significant pull load after threading a mandrel into the plug skirt.
While the pull load on the plug skirt was increasing, the bottom portion of the plug broke away from the plug and remained with the removal tool. Approximately 1 1/8 inches of the plug broke free, which is at the fourth land of the plug. The maximum hydraulic pressure observed was 3000 psi.
The 3000 psi hydraulic pressure would indicate about 8000 lbs force was applied to the plug skirt before it broke free, although this is not an indication of the load capacity of the bottom portion from the plug relative to the top of the plug. The interference engagement of the top land of the plug fragment with the tube inside diameter could have contributed to the required force necessary to remove the lower portion of the plug.
A visual examination by FPL personnel of the plug fragment indicated that the entire surface of the break was covered with a black oxide.
Westinghouse will provide a final evaluation after the lower portion of the plug and other plug fragments are analyzed by Westinghouse.
J'PN-PSL-SEMS94-026 REVISION 1 PAGE 9 of 17 3.4.2 VALIDITY OF THE CORROSION ALGORITHM The appearance of wet or leaking plugs does not invalidate the assumptions of the corrosion algorithm in Reference 4b. The projections of the algorithm are for the time to the occurrence of essentially a 1004 through-wall 360 circumferential crack ("plug top release" ). The projections of the algorithm are not applicable to axial or limited circumferential through-wall cracks.
Reference 4b states that 37% of field plugs sampled with usage factors in excess of 0.63 were found to contain PWSCC cracks. Of the known instances since Reference 4b was prepared, there have been only three plugs that had leakage in the plug. All of these plugs had a usage factor of 0.86 or greater. The extremely low frequency of Inconel 600 mechanical plugs reported to be cracked by evidence of leaking demonstrates the conservatism of the algorithm.
For comparison, the 506 St. Lucie hot leg'lugs have a usage factor of 0.58. This is close to the usage factor for the sample of field plugs of which 37> had cracks.
Thus, these observations of cracking fall within the expected distribution for PWSCC.
3.4.3 PROBABILITY OF CIRCUMFERENTIAL CRACKS A French utility documented an examination Their of 16 mechanical plugs of Westinghouse design. ~
that through-wall axial cracking would be report'ndicates expected to be four times more likely to occur than through-wall circumferential cracking. Also, the through-wall circumferential cracking below the plug expander (i.e. non-pressure boundary area) would be expected much more often than above the expander.
Thus the data from this examination tends to confirm that a plug top release event would be expected to be extremely rare, and plug leakage is most likely due to an axial crack. F
O ZPN-PSL-SEMS-94-026 REVISION 1 PAGE 10 of 17 3.4.4 BASES FOR PLUG TOP RELEASE NOT PERFORATING TUBE Reference 4b cited several reasons to leave the Westinghouse plugs in service until near the date pro j ected by the corrosion algorithm. These reasons qualitatively assess the potential for a plug top release to perforate the tube in which the plug was installed.
References 4a and 4b document that in the event of a plug top release, perforation of the tube would be unlikely if the plug is in tube row numbers 5 or greater. This was based on dynamic testing and analysis.
The appearance of axial or limited circumferential through-wall cracks in a plug equalizes pressure across the plug which precludes a plug top release event. Plugs with circumferential or axial cracks are expected to leak prior to full circumferential cracking.
If a plug top release did occur, pre-existing axial or limited circumferential through-wall cracks would minimize the potential for perforation of the tube in any row, since there would not be sufficient energy for the plug top to traverse the tubesheet.
release would occur It is more during plant likely that a heat-up or plug top cooldown operation or postulated main steam line break.
Plugs in tubes with through-wall cracks would be less likely to experience a plug top release since the secondary pressure would reduce the axial stress.
>~
None of these reasons are invalidated by the subject observations at St. Lucie.
3.4.5 IMPACT ON NRC LONG TERM ACTION PLAN Continued verification of the corrosion algorithm based on field data was part of the long term action plan between Westinghouse and the NRC (Reference 9).
Based on the information presented in sections 3.4.1 and 3.4.2, Westinghouse judged that the St. Lucie plug leakage was most likely a result of axial or limited circumferential cracking in the plugs above the expander.
If axial or limited circumf erential cracking above the expander is found, the corrosion algorithm would be modified by setting the PWSCC usage factor for that heat to 0.74,- and use a more conservative microstructure factor.
On this basis Westinghouse revised the algorithm as described above. The remaining time from the current outage prior to the occurrence of a plug top release in the steam generator hot leg is estimated to be 3.0 effective full power years (EFPY).
O JPN-PSL-SEMS-94-026 REVISION 1 PAGE 11 of 17 3.4.6 WESTINGHOUSE CONCLUSZONS Westinghouse concluded that it is acceptable to take remedial action only for the leaking tube plugs and any Westinghouse plugs in hot leg channel head tube rows 1
- 4. The remaining tube plugs have a remaining service life of 3.0 EFPY from this outage, prior to an expected plug top release.
Remedial action on the Westinghouse mechanical plugs in hot leg channel head tube rows 1 4 is necessary to assure that all remaining tube plugs are bounded by the dynamic (air gun) testing for tube perforation.
EVALUATION 4 ' REGULATORY BASIS FOR RCS LEAKAGE AND S/G TUBE ZNTEGRITX Technical Specification LCO (Section 3.4.6:2) for primary to secondary leakage is one gallon per minute (1 gpm).
The basis for this LCO, in conjunction with the LCO for RCS specif ic activity, is to ensure the dosage contribution will be limited to a small fraction of 10 CFR 100 "Reactor Site Criteria", in the event, of a steam generator tube rupture or steam line break accident.
These design transients are discussed in the FSAR and will be reviewed herein.
The Technical Specification basis (Section B.3/4..4.5) for tube integrity is to maintain surveillance of the tube condition and take corrective measures (e.g. plugging),
consistent with Regulatory Guide 1.83 Rev. 1. The extent of tube cracking during plant operation is limited by maintaining primary to secondary leakage less than 1 gpm.
This will ensure an adequate margin of safety to withstand the loads imposed during normal operation and postulated accidents.
There are no Technical Specifications or bases specifically directed toward steam generator tube plugs.
The plugs are designed to remove from service degraded tubes which exceed the plugging limit. Since the plugs are designed to maintain the primary to secondary boundary of the steam generator, they must be included in any consideration of primary to secondary leakage.
J'PN-PSL-SEMS-94-02 6 REVISION 1 PAGE 12 of 17 4 ' TUBE AND TUBE PLUG INTEGRITY EVALUATION There have been no reported plug top release events prior to the date predicted by the Westinghouse algorithm for any material heat in the industry. Therefore, it is highly unlikely that these tube plugs would have a plug top release prior to 3.0 EFPY from this outage.
Should these plugs leak, the most probable failure mode is an axial crack or limited circumferential crack which precludes plug top release. Should a plug top release occur, consequential tube damage should not occur for tube rows 5 or greater. The two Westinghouse plugs in tube rows 1 through 4 will be replaced; Predicting the occurrence of circumferential cracking below the plug expander is not within the scope of the Westinghouse algorithm, because cracking below the expander does not result in a plug top release event.
Should significant circumferential cracking occur below the expander, it is not expected that the bottom portion of the plug would retract from the tube and become a loose part and migrate in the reactor coolant system, based on the following reasons.
- 1) Westinghouse observed during the plug removal effort that a significant tensile force was needed to dislodge the bottom portion of the plug from the tube, even though the separation point had extensive corrosion. The interference of the plug skirt, lower sealing lands with the inside diameter of the tube probably provides the resistive force. Tensile forces at a potential plug crack below the expander are not present during plant operation, since this part of the plug is not subject to significant differential pressure. Therefore it is unlikely that the bottom portion of the plug could retract from its host tube.
- 2) Westinghouse reported that there have been no reported occurrences in the industry of a bottom portion of the plug becoming a loose part.
- 3) If the bottom portion host tube, it of the plug did retract from its is highly unlikely that the fragment could enter an active tube, since the skirt outside diameter would have to be aligned with the tube inside diameter. This piece should be detectable by the loose parts monitor system on the steam generator (FSAR section 5.2.5.2).
It is concluded that steam generator tube and tube=-plug integrity will be maintained.
JPN-PSL-SEMS-94-026 REVISION 1 PAGE 13 of 17 4 ' EFFECT ON FSAR SAFETY ANALYSES The accident analysis presented in Chapter 15 of the FSAR will be reviewed in two categories: steam generator tube rupture, main steam line break. Other postulated FSAR events are bounded by these two scenarios for potential tube and plug leakage.
4 '.1 STEAM GENERATOR TUBE RUPTURE (SGTR) is ~ 4 '
FSAR SECTION The FSAR analysis postulates the random failure of an active steam generator tube. Since the primary to secondary differential pressure is less for a SGTR than during power operation, the stresses imposed on the tubes and plugs would not be any greater than normal power operation. The probability of a plug release would be no greater during a SGTR event than during normal operation.
Per Attachment 3, a tube plug top release is not predicted prior to 3.0 EFPY from this outage, and a plug top release has not occurred earlier than predicted. Also, testing has demonstrated that a plug top release would not perforate its host tube. Therefore, it is highly improbable that a tube plug top release would occur prior to 3.0 EFPY from this outage, and perforate the tube.
However,,should a plug top release and result in a tube failure, the maximum leakage through the plug is limited to 80 gpm (Reference 4a), which is bounded by the FSAR SGTR event. The maximum leakage is only SQ gpm, because the expander in the plug serves as a leak limiting device (Reference 4a). A total of seven plug top releases and tube ruptures would be required to occur to exceed the analyzed steam generator tube rupture event (Reference 4a). It is not credible to postulate multiple tube and plug failures concurrently.
Therefore the consequences of a postulated SGTR are not affected by the Westinghouse mechanical tube plugs.
e J'PN-PSL-SEMS 94 026 REVISION 1 PAGE 14 of 17 4 ~ 3 ~ 2 MAIN STEAM LINE BREAK (MSLB) FSAR SECTION 15 ~ 4 ~ 6 The FSAR analysis postulated the random failure of a main steam line inside containment.
Concurrent plug top release during a steam line or feedwater line break is not expected, since the potential for plug top release is greater during normal operation or cooldown (Ref. 4a). The tube plugs have been qualified for greater than full primary differential pressure (i.e.
2250 psid), per Reference 3. The probability of a plug release would be no greater during a MSLB event than during normal operation. Therefore, plug integrity would be no different during a steam line break or feed line break; compared to normal plant operation or cooldown.
Should a. plug top release during a MSLB event, expected to cause consequential tube damage.
it is not Therefore the consequences of a postulated MSLB are not affected by the Westinghouse mechanical tube plugs.
JPN-PSL-SEMS-94 026 REVISION 1 PAGE 15 of 17 5 ' CONCLUSION AND RE UIRED ACTION It is concluded that leakage from the fifteen Westinghouse plugs was most likely caused by an axial or limited circumferential crack in the plug above the expander. Based on the revised Westinghouse algorithm, a plug top release in the remaining Westinghouse plugs is not expected for 3.0 EFPY from this outage (approximately 2.25 fuel cycles).
However, in the unlikely event that a tube plug top release occurs in the remaining Westinghouse plugs during plant operation, analysis.
it is bounded by the existing FSAR accident The required actions this outage are to replace the tube plugs described below (See Attachment 2 for specific tube plug location).
- 1) The fifteen leaking Westinghouse tube plugs shall be removed and replaced.
') Two Westinghouse repaired or replaced.
tube plugs in tube row 4 shall be This is a preventative measure because dynamic testing for tube perforation did not bound rows 1 4.
- 3) The two leaking ABB/CE welded tube plugs shall be removed and replaced.
The following long term actions are recommended:
- 1) Continue to inspect the installed Westinghouse steam generator tube plugs for evidence of leakage during the next refueling outage.
- 2) If the removal of the Westinghouse plugs provide a suitable artifact, these should be examined to characterize the PWSCC.
In summary, (1) A plug top release event is unlikely to occur because cracking above the expander is expected to be axial or limited circumferential in orientation. (2) if a plug top release event does occur the plug top would not perforate the tube based on dynamic air gun test results, (3) the majority of tubes with Westinghouse mechanical plugs were removed from service for preventative reasons, (4) Circumferential cracking, which does not result in a plug top release, is expected to occur below the expander prior to the occurrence cracking above the expander, (5) It is unlikely that cracking below the expander will result in the bottom portion of the plug becoming a loose part, due to the physical interference from the plug skirt, lower sealing lands and the tube.
Therefore, a plug top release is not expected to cause a tube rupture, and a circumferential crack below the expander is not expected to cause a loose part.
t JPN-PSL-SEMS-94 026 REVISION 1 PAGE 16 of 17 6 ' VERIFICATION
SUMMARY
The scope of this verification was to review the input and references to determine if the results/outputs were reasonable in comparison to the inputs. The method used for this verification consisted of ensuring that the applicable references, codes, and regulatory requirements were addressed and properly reflected herein. The results/outputs provided are reasonable with respect to the inputs. The verifier concurs with the Safety Related classification of this Engineering Evaluation.
7 ' REFERENCES
- 1. St. Lucie Unit 1 Final Safety Analysis Report through Amendment 13
- 2. St. Lucie Unit 1 Technical Specifications through Amendment 129.
- 3. Standard ¹STD-QS-1989-4359, "Steam Generator Mechanical Plug Qualification Summary for 3/4 In. Diameter...Tubes>>,
Revision 0 (Westinghouse Proprietary Class 2).
4a. Addendum 1 to WCAP 12244, Westinghouse Tube Plug Integrity Report, Revision 2 (Westinghouse Proprietary Class 2).
4b. Addendum 2 to WCAP 12244, Westinghouse Tube Plug Integrity Report, Revision 3 (Westinghouse Proprietary Class 2). P ~,
- 5. Safety Evaluation JPE-PSL-SEMJ-88-041, Revision 1.
- 6. Safety Evaluation JPN-PSL-SEMJ-89-52, Revision 0.
- 7. FPL letter L-91-207, Bohlke to NRC, " St. Lucie Units 1 and 2, Docket Nos. 50-335 and 50-389, NRC Bulletin 89-01, Response to Supplement 2", dated 7/29/94.
- 8. Westinghouse letter NSD-RFK-94-014, " Evaluation of Reported Leaking Mechanical Plugs at St. Lucie Unit 1",
dated 11/10/94.
- 9. WCAP-12519 (Proprietary), Steam Generator Tube Mechanical Plug Long Term Action Plan Meeting with the NRC" 1/90.
JPN-PSL-SEMS 94~026 REVZBZON /
PAGE 17 of 7.7 FIGURE 1: SCHEMATIC OF INSTALLED WESTINGHOUSE MECHANICAL TUBE PLUG (From Reference 4a) gGM';P.
pl q ggpphlDCQ S~k~y 4o~~
CT)pjMLJ UNEXr wnm EXPANBEB QKSTINHOUSK HECIINICAt. PNG
ATTACHMENT 1 11 E l OF 2 TO ZPN-PSLIHrtS-94-926 REV. D ST. I UCIE ACTION REPORT STAR IDENTIFICATION SECTION Date~~ STAR¹ /I0 9 Person/Department Initiati -CSK Description Yh S 646 <cl Unit s L.c 5 O
~.p Io ;I amr lcr c ea.taA lndMdual Notified Location CC Roferences (io, NRC Butkrtin ¹, Audi Report, O Drawing ¹, personnel observation, etc.) Yes No
- 1. Weroanystopstakentomitigate? Q Yes Q No
- 2. What were they and were they successful?
- 3. Suspected cause of condithn. +r 4 Or
- 4. Recommendation to correct and department responsible. '4 6 p<
ea rC
-<~ Do you require approval to dose? Yes Q No Date REVIEWAPPROVAL
- 1. Assignod Departmen//nddfviduaL . f r n.h <P U
- 3. NP.700
- 4. Evaluation due by ~~s<<HPES Q
<l Corrective measures completed by lr
~~
S'ature Date i Do You reeuho approval to erose? H Yes Q No
- 1. Notifications. O.e., AP 0010721. 'NRC Required Non Routine No ifications 8 Ap 0005762, 'phnt Gukfe to Reponing Environmental Reports'Yes N~priancos QNo cf.'. 0006125, 'Reporting of Safeguards E~ and SigniTicant Events'P Event Typo 1s6 Q Yes Q No Q Pop Q
~
- 3. Security evont IHE ate
- 1. Is operabliity assessment needed for continued operation2 Q Yes Q No
- a. Does tats tram put us tn an a noon stsenenrr
- 3. Does this item dedare asystem orcomponentOOS?
Yes Q Yes No
'o Yrrnntpate What equipmo Duraenn v) 4. What immediate notifications were made? (NRC, EPA, etc)
K
- 5. Isltomamodehold? Q Yes Q No Priorto Q Q Q Q Q Q
- 6. Additional comments/actbns taken.
ignature (Q/-1&28. WPG) (Rev. 0 7P/94)
ATTACHMENT 2 PIIS 2 OF 2 TO JPN-PSL4MS-94-026 RHV. 0 ST. LUCIE ACTION REPORT STAR IDENTIFICATIONSECT/ON Date~~
Person/Do partment Initiati I- - C5 X Description Ys S EEA CCl Unit System s Le o I R'cs'ndividual yp '4 e ~ Ay tsC t C ya.taA Notified Locatira References (ie, NRC Bulletin ¹, Aud'eport.
Drawing ¹, personnel obstavation, etc.) Operator woikaro nd Q Yes
- 1. Wereanystepstakentomitigate? Q Yes g No
- 2. What were they and were they successful?
- 3. Suspected cause of conrfitfon. +r 4 or - r 6.
- 4. Recommendation to correct and department responsible. I s i~
Department Heed -5 ~ Do you require approval to dose? Yes Q No Date REVIEW'APPROVAL
- 1. Assigned DepaitmongndividuaL ~ L 6'+4
- 3. NP-700
- 4. Evaluation due by ~~ H II S 94 Cottoctfve measures completed by~~
S'ature Ir Date i Do you renuiro approval lo arose? P Yes Q No
- 1. Notifications. g.e., AP 0010721, 'NRC Required Non Roufine Notifications 8 Reports'Yes AP 0005762, 'Plant Guide to Reporting Environmental Non~pfiances and SigniTicant Events'
@No SP 0006125, 'Reporting of Safeguards Events' CII
- 2. Event Type lus 07
- a. Emmmy~m Qvm Qtto Q
- 1. Is operability assessment needed for continued opemtion?
- 2. Does ass item put us in sn aayon slatmenty
- 3. Does this itemdedareasystemorcomponent
- 4. What lmmediato notifications were mad o? (NRC, EPA, etc) yop Q Yes Q No
'es Q No ylmeiDate Q
Q Yos Q No Whatequip tttE
~ yg nature Duraaon ate R
- 5. Is item a mode hold? Yes Q No Prior to
~
- 6. Addithnal comments/acdons taken.
(Q/-7628 WPG) (Rev. 0-7p/94)
ATTACHMENT 2 E / OF 2 TO JPN-PSL S-94-026 REV. 0 Inter-Office Correspondence JPNZSI-94-506 To: K. R. Craig ~Q Date: November 11, 1994 From: G. L.
p Beyeregr'ept.: JPN/CSI
Subject:
PSL-1 STEAM GENERATOR PLUGS IDENTIFIED LEAKAGE - STARi}'4110347
Reference:
Letter JPN-CSI-94-501, GL Boyers to KR Craig (same subject)
Since the reference memo was issued additional leaking Westinghouse plugs have been identified in the hot leg of the A and B steam generators. This memo (1) replaces the reference memo, (2) lists all known leaking plugs,.and (3) lists any additional plugs recommended for repair.
'S.L iA i ITA~ }rrr\03r iidr Westinghouse mechanical plug and indicates that additional suspect areas were identified which may contain leaking plugs. This memo provides resolution of those remaining suspect areas.
Video tape review was completed which identified several suspect areas with boron build up and/or moisture accumulation. Additional video recordings were completed and reviewed on 11/6/94 and 11/10/94. The attached list idehtifies plugs confirmed as leaking and additional plugs recommended for repair.
The Westinghouse mechanical plugs listed were installed in 1984 and appear to be leaking from the I.D. bore of the plug. A rod was inserted through the expander to verify that the plug top is present on all leaking Westinghouse tube plugs listed. There are approximately 500 plugs of this heat between the A and B S/G hot leg tubesheets. Continued service for these plugs should be addressed by an engineering evaluation as part of the STAR completion.
The ABB welded plugs listed were observed to have heavy boron accumulations.
These accumulations were removed and later video recordings show that boron accumulations reformed after 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />. Subsequently, these plugs will be scheduled for repair/replacement.
cc: W. H. Bohlke J.T. LaDuca J. T. Luke R. F. Gross K. K. Mohindroo D. J. Denver T. F. Dillard A. J. DeGrasse W.K. Heise K. E. Corbitt Fortn 1008 tstocttedl itev. gl89
ATTACHMENT 2 E 2- OF 2 TO JPN-PSL MS-94-026 REV. 0 JPN CSI-94.505 PSL-1 STEAM GENERATORS Pepe 2 of 2 TUBE PLUGS RECOIVIMEDED FOR REPAIR NOVEMBER - 1994 T BE LUGS DETERIVIINED TO BE LEAKING
~ A A
~LE HOT HOT ROW 8
8 JLNE 42 44, PL G YP Mechanical Mechanical MANUF W
W A HOT 8 160 Mech anicat W A HOT 9 45 Mechanical W A HOT 10 56 Mechanical W A HOT 10 118 Welded ABB A HOT 11'4 15 IVtechanical W A HOT 100 Mechanical W A HOT 104 102 Welded ABB B HOT 8 18 Mechanical W B HOT 8 44 Mechanical W B HOT 8 132 Mechanical W B HOT 9 23 Mechanical B HOT 9 45 Mechanical W B HOT 10 140 Mechanical W B HOT 11 47 Mechanical W B HOT 11 57 Mechanical W DDITI NAL PLUGS RECOIVIIVIENDED FO REPAIR WHICH ARE NO NDED B DYNAIVII IR N TES W A 12244
~
B
~LE ~lW PUULYYPE ~*" W A HOT 4 154 Mechanical B HOT 4 132 Mechanical W ps!leek.506
ATTACHMENT 3 OF JPN-PSL-SEMS-94-026 REV 0 This attachment contains Class 2 Westinghouse Proprietary Information and is available for onsite review.
ATTACHMENT 4 1E ~ OF TO JPN-PSL-a46-94-026 REF. 0 To: K. R. Craig From: R. J. Frechette ( ate: 11/7/94
Subject:
Status of PSL-1 Steam Generator tube leaks During the most recent fuel cycle on PSL-1 no primary to secondary leakage was detected from the 1B Steam Generator.
The 1A Steam Generator continued to exhibit a very small amount of leakage that has appeared intermittently since 1986.
This leakage was sized in 1992 at approximately .017 gal./day, it reappeared briefly during a shutdown in June of this year.
The leak is still very small and was detected while the Unit was in Hot Standby, and the Steam Generator outflow was at a minimum. When the Unit was recovered and place/ back in service, the 1A Steam Generator Gross Activity returned to less than MDA. Chemistry reinitiated large volume sampling of the 1A Steam Generator to continue to monitor for leakage.
Detectable Cobalt activity was indicated on 400 liter mixed bed resin samples thru August, while the last samples taken prior to shutdown were less than MDA. During the entire cycle 4 liter samples were performed monthly in addition to the every other day Gross Activity samples and no other instances of leakage was detected.
Copies to: J. Scarola G. Boyers K. Beichel
ATTACHMENT 5 OF JPN-PSL-SEMS-94-026 REV 0 This attachment contains Class 2 Westinghouse Proprietary Information and is available for onsite review.