ML20058K119
| ML20058K119 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 10/31/1989 |
| From: | Bates R VIKING SYSTEMS INTERNATIONAL |
| To: | NRC |
| Shared Package | |
| ML20058K124 | List: |
| References | |
| CON-NRC-03-87-028 GL-88-01, NUDOCS 8911090141 | |
| Download: ML20058K119 (32) | |
Text
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TECHNICAL EVALUATION REPORT ON-RESPONSE PIOf-ILLIN0IS POWER COMPANY TO GENERIC LETTER 88-41 PERTAINING 10 THE
,. CLIN 10N POWER PLANT a .
Published October, 1989 . prepared by Robert C. Bates Armand laknar Viking Systems International 2070 Wm. Pitt Way
; Pittsburgh, PA .
, Prepared for:
U.S. Nuclear Regulatory Commission Washington, D. C. 20555 FINtj. under Contract No. NRC4 3-87-028 Task Order 005 h .
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i This report contains an evaluation'of the licensee (Illinois Power ll Company) submittal for the Clinton Power Station which was submitted - in response to the NRC Generic Intter 88-01 in which Illinois Power i was requested to (1) Furnish their current plans relating to piping . 4 replacement and other measures to'aitigate IGSCC, inspection, repair, j and leakage detection. (2) Indicate whether they plan to follow the . .
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NRC Staff positions, or propose alternative measures. Illinois Power's 1 o l L plans are evaluated in Section 2 of this report in terms of compliance to NRC Staff positions. Illinois Power did not present any alternative j posit 4,ons to those of the NRC Staff. e e 4 e s a
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, i The Licensee, Illinois Power Company, submitted a response to the NRC l t Generic Letter 88-01. Illinois Power's response pertaining to the I austenitic stainless steel piping in the Clinton Power Station, (a c BWR nuclear power plant) was evaluated in terms of (1) Their previous and planned actions to mitigate IGS00 to provide assurance of continued '
long-term service. (2) '! heir Inservice Inspection (ISI) Program. ;
.I (3) Their Technical Specifications pertaining to ISI and their plans to ensure that leakage detection will be in conformance with the NRC ;
Staff position. (4) Their plans to notify the NRC of significant flaws identified (or changes in the condition of the welds previously known i to be cracked) during inspection and evaluation of such flaws. , 4 . Illinois Power accepts all of the 13 NRC Staff positions which are i outlined in Generic Letter 88-01, although they applied provisions to two (i.e., Inspection Methods and Personnel and Leakage Detection). - Their provision on inspection methods and personne1'is applied to extend inspection methods to welds with corrosion resistant cladding. Their position on leakage detection (with their attached provision) is acceptable except for frequency of Jeakage monitoring. As a result of previous mitigating actions most welds in the austenitic : stainless steel systems at Clinton are classified as IGSCC Categories A, but many of these are incorrectly classified. Clinton has 28 welds ' in nozzle assemblies which contain Inconel 182 and are classified as IGSCC Category D. No additional treatments are planned, although stress [ improvement is being considered for the nozzle assembly welds, and HWC is> planned. ' Inspection plans are in compliance with the NRC Staff positions on schedules, methods and personnel (except for the provision), and sample expansion except for the incorrectly classified welds. In addition, Illinois Power agreed to submit an amendment to their Technical Speicifcation on ISI as requested in Generic Letter 88-01. P e
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'[ CON 111NTS I ABSTRACT i .
SUMMARY
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. i j 1. INTRODUCIlON 1 l
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., 2. EVALUATION OF RESPONSE TO GENERIC LETTER 8801 2
,- 2.1 Documents Evaluated 3 2.2 Review of Illinois Power's Respua to Staff 3 =;
Positions and Implementation of Those Positions i 2.3 Review of IP's Previous Mitigating Actions, 4 ; l;
- Classi5 cation of Welds, and Previous Inspection Program i 23.1 Summary of Previous Actions 4 i i
23.2 Materials and Weld Classifications 4 ! (per Illinois Power Submittal No.1) H 233 Materials and Weld Clusifications 6 . (per Illinois Power Submittal No. 2) . .
- i. l 2.3.4 Hydrogen Water Treatment 9 l J
l. 23.5. Previous Inspection Program 9 23.6 Evaluation and Recommendations 9 L 2.4 Current Plans for Mitigating Actions 11 m 2.4.1 Hydrogen Water Chemistry 11 f 2.4.2 Stress Improvement 12 2.4.3 Evaluation and Recommendations 12 1 2.5
- Current Inspection Program 12 1
2.5.1 Inspection Schedules 12 F 2.5.2 Inaccessible Welds 13 2.5.3 Methods and Personnel 13 2.5.4 Sample Expansion , 14 l . i11 .
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2.5.5 Evaluation of Inspection Schedule and Raarunmandatlan 15 . ! , m.. 2.6 -. Changes in the Techn' s al Specificatiori Concerning ISI- 15
%. 2.6.1 Blinois Powa& Position 15 a ?j)
- 2.6.2 . Evaluation and Recommendation 16L f
e' 2.7 - Confirmation of I.mak Detection in Technical Speci5 cation . 16 ' L' , 2.7.1- Illinois Power's Position - 16 lt 2.7.2 Evaluation and Recommendations 20 l'.
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2.8 Plans for NotiGcation of NRC of Plans - 22 Illinois Power Submittal 1,$. I contains - zai 22 l , the following statement llx , 2.8.2; Evaluation and Recommendation 22-lR ' 3. . ALTEANATIVE POSITIONS AND REQUEST FOR RFI fMF 22'
- 4. . CONCLUSIONS AND RECOMMENDATIONS -
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- 5. REFERENCES . 26 g
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~l- 1. INTRODUCTION
. Intergranular stress corrosion cracking (IGSCC) near weldsents in Bon . s Water Reactor (BWR) piping has been occurring for almost 20 years.
t l Substantial efforts in research and development have been sponsored by the BWR Owners Group for IGSCC Research, and the results of this { program, along with other related work by vendors, consulting firms and confirmatory research sponsored by the NkC, have permitted the development of NRC Staff positions regarding the IGSOC problems. The technical basis for NRC Staff positions is detailed in Reference 1, and further background is provided in Reference 2. The results of these research and development programs prompted the NRC to issue Generic Letter 88-01 (see Reference 3) requesting all licensees of BWR's and holders of construction permits tot (1) Furnish their current plans relating to piping replacement, inspection, repair, and leakage detection. (2) Indicate whether they: (a) Plan to follow the staff positions, or (b) Propose alternative measures. Specifically, Generic Letter 88-01 stated that an acceptable licensee response would include the following items: (1) Current plans regarding pipe replacement and/or other measures taken er to be taken to mitigate IGSCC and provide assurance of continued long-term piping integrity and reliability. (2) An inservice inspection (ISI) program to be in plemented at the next refueling outage for austenitic stainless steel piping. (3) A change to the Technical Specifications to include a statement 1 I
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'i in the section on ISI that the inservice inspection program for piping will be in conformance with the staff positions on schedule, methods and personnel, t
l (4) Confirmation of plans to ensure that the Technical Specification related to leakage detection will be in conformance with the Staff position on leak detection. (5) Plans to notify the NRC, in accordance with 10CFR50.55a(o), of any Daws identified that do not meet IWB-3500 criteria of Section II of the ASME Code for continued operation without evaluation, or a change found in the condition of the welds previously known to be cracked, and an evaluation of the flaws for continued operation and/or repair piens. This report contains a technical evaluation of the response which Illinois Power Company (called either Illinois Power or IP in this report) submitted in response to the NRC Generic Letter 88-01 pertaining to the Clinton Power Station (hereafter called Clinton or CPS).
- 2. EVALUATION OF RESPONSE 10 GENERIC LETTER 88-01 This evaluation consisted of a review of the response to NRC Generic 1etter 88-01 of January 25, 1988 by Illinois Power pertair.ing to Clinton to determine if their performance and plans are in conformanc*
with the NRC Staff positions or if proposed alternatives are acceptable. Proposed inspection schedules and amendments to the Technical Specification were included in the review. 2
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pg se - 4,b 2.1 Documents Evaluated
" Review was conducted on the information pertaining to Clinton provided by the Licensee in the following documents:
(1) "Clinton Power Station, (Rosponse to) Generic Letter 88-01," Docket No. 50-461, Illinois Power Company, Clinton Power Station, P.O. Box 678 Clinton, Illinois 61727, July 29, 1988. (2) "Clinton Power Station, (Response to Request for Additinnal Information) Generic Letter 88-01," Docket No. 50-461, Illinois Power Company, Clinton Power Station, P.O. Box 678, Clinton, Illinois 61727, September 21, 1989. Hereafter, in this report, these documents will be referred to as Illinois Power Submittals No. I and No. 2, respectively, and , collectively, as the Illinois Power Submittals. 2.2 Review of Illinois Power's Responses to Staff Positions and Implementation of'Those Positions Generic Letter 88-01 outlines 13 NRC Staff positions pertaining to (1) materials, (2) processes, (3) water chemistry, (4) weld overlay, (5) partial replacement, (6) stress improvement of cracked weldments, (7) clamping devices, (8) crack evaluation and repair criteria, (9) inspectton methods and personnel, (10) inspection schedules, (11) sscple expansion, (12) leak detection, and (13) reporting requirements. Generic Letter 88-01 states that the licensee should indicate in their submittal whether they endorse these NRC Staff posi'. ions or propose alternative positions. Illinois Power Submittal No. 2 addresses each of these items, and that response along with information provided in Illinois Power 3 : l 1 3 m
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~ Submittal No. 1 'is'summarised in Table 1 of this report.
h "9-4 Y ,. Note that Illinois Power indicated acceptance'of all thirteen of, ' 1
'the.NRC Staff positions,'although they' applied provisione to
+i :two; 1.e., those pertaining to Inspection Method and Personnal and ,
4 , . i: , 14ak Detection. These two' items are discussed in Sections 2.5 and J, 2.7, respectively. s. d ~. 2.3 Review of IP's Previous Mitinstina Actions. Classification-L , of Welds. and Previous Inspection Pronras
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e j, 2.3.1 Summary of Previous Actions ; y i,- , Material'and processing changes were made during design and-
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L 1 construction which eliminated most corrosion susceptible ; piping. These changes' included the use of corrosion resistant materials and ID cladding-as discussed below. - '
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i 4!' ' ~ 2.3.2 Materials and Weld Classifications (per Illinois Power Submittal No. 1) ~ . h
' Illinois Power Submittal No. 1. states: j g!
- , "With the' exception'of the Reactor Recirculation System piping, all stainless steel' piping in contact with the l
reactor coolant-is 316L stainless steel and, therefore, has less than 0.03% carbon content. The Reactors
., Recirculation System piping'~1s fabricated'primarily of ,
L l'{3 304 stainless steel. Certain portions of the piping = a, .have been changed to ' nuclear grade' type 316 stainless , i steel which contains less than 0.03% carbon. The remainder hs had ~ ' Corrosion Resistant Cladding' (CRC) applied in the v.'cinity of field welds so that no heat-affected type 4 m ,
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- Sumary of IP's Responses to Staff Positions
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'4' IP Bas /Will .
Applied Consider for
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. . 'IP Accepts NRC o: <
Staff Position Staff Position In Past Puture Use
- 1. - Materials -- yes yes no(a).
- 2. Processes. yes yes- no(a)-
g[f 3' Water Chealstry yesz .no( ) yes t <4; Weld Overley yes no ao. s.[ :5. Partial Replacement yes yes no(*)^ F '6.< Stress Improvement of Cracked Waldsents yes NI yes IC)
- 7. Clamping. Devices yes . NI no
- 8. Crack Evaluation and
~ Repair Criteria- yes NI yes -
.9.' Inspection Method '
yes(d) and Personnel 41 yes(d)
- y; - 10.' Inspection Schedule yes NI yes
- 11. Sample Expansion yes NI
_ y,, WI 12.LLeak Detaction yes(d) y,,(d) 13,1 Reporting Requirements- yes- NI yes a h '; i .. (a) Material.and processing steps were taken during construction of
-Clinton to mitigate intergranular' stress' corrosion cracking.
(b) A Hydrogen iiator Chemistri treatment system is being designed. (c) Stress improvement is N ing considered for.24 Inconel buttered
;, , nozzle assemblies; be*,. the success of HWC will be used to determine W -' ff the'es treatments will be applied.,
(d). Provisions applied. Coe text-for discussion. V : i1-D 3:7 i I N g J, 3 t L. -.
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,% 304 stainless steel will be in contact with the reactor j
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' coolant. The' piping assemblies were solution annealed i
after all shop welding and application of-the CRC."-
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- All welds described in the preceding paragraph are, accordingi l M; 'te' Illinois Power. Submittal No.1, classified as IGSOC Category A.>
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. Illinois Power Submittal Submittal No..I also states:
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" Reactor Pressure Vessel (RPV) attachments and
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- appurtenances: The RPV head spray and vent piping is'made of carbon steel classified as_P-1 by the American Society; q -
of Mechanica1' Engineers (ASME) Boiler and Pressure. Vessel
, i Code and is therefore not susceptible _to IGSCC. None ,
of the;RPV internal components require volumstric 3
- examinations in accordance with Section=II of the ASME- *
,'< , Code. Twen'ty-four (24) Clinton Power _ Station (CPS) RPV' v.
1 nozzle assemblies have Inconel 182 buttering at their safe-end connections. 'Of the twenty-four-(24),- -
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twenty-three (23) require ultrasonih testing (UT). ' The 1
,, control rod drive nozzle safe-end connection does not i
~ require UT because it is-less than four inches in- l diameter." I
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'he 23' nozzle assembly welds described above are, according to Illinois Power Submittal No. 1, classified as IGSCC Category l D.
q v. ; h.. 2.3.3 Materials and Weld Classifications ll,1 (per Illinois Power Submittal-No. 2) m_. " )
* ~Since the Illinois Power Submittal No. 1 does not contain 1 l . a weld-by-weld listing of the welds giving their compositions y
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l?$ (or materini identifications) and IGSOC classifications, such information was requested in a Reply for Additional Information. In response to that RAI, Illinois Power Submittal No. 2, was provided, and that submittal contains such a list, although nunc.rous longitudinal welds (d ich are not included in the scope of Generic 1,etter 88-01) are included in that list. A summary of that information (excluding the longitudinal welds) is contained in Table 2 of this report. In that table, the welds are listed as containing resistant asterial if the upstream component, downstream component, and weld metal all contain resistant material per NUREG 0313, Revision 2. Welds are listed as containing non-resistant if one or more of those portions of the weld assembly contain non-resistant meterial per NUREG 0313. Contrary to statements in Illinois Power Submittal No. 1 (quoted in Section 2.3.2 of this report), a large portion , of the piping system welds contain non-resistant materials and have not received mitigating treatments. Note, from Table 2, that all welds in the Recirculation System, all of the Residual Heat Removal System, and four of 8 welds in the Reactot Water Clean Up sy' s tem contain non-resistant material. In most cases either the upstream component or the downstream component (or both) is listed in the table in Illinois Power Submittal No. 2 as containing either Type 304 or Type 3 h stainless steel. Both of of these materials are considered as non-resistant per NUREG 0313, Revision 2. The weld metal in several of the welds is listed as containing Type 308 or Type 309 filler metal. Thesematerialsarealsocon)idered as non-resistant per NUREG, Revision 2. Fifty-three of these welds have been solution heat treated, and 28 have received corrosion resistant cladding. However, 78 of the non-resistant welds have not received any mitigating treatments. 7 N
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IGSCC Classifications, Materials, and Mitigating Treatments-r gp, _ IGSOC No. of. No.'with- No. with Non-Res. Matl & se J,I,s,,j;.e,tm . fat,gg Welds Res. Nati Non-Res. Matl SHT J},Q, No Treatment
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yg, - Noz/SE 'A' 10- 10: . Mhi,h D- 28 28 s 28. m . -s '!.h[
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Recirc 'A 123 123 53' 28 "42 : (p
. ;g RER- A. ~ 4. 4 4 RWCU- AL '8 4 4' -4 U Totals 173 14 159 '53 28 78:
1.: L' , Abbreviations: ' e ., Noz/SE - Reactor Pressure Vessels. Nozzle to safe end "and q safe end extension welds. 4 Recire. Reactor Recirculation System i 4
;RHR- -- Residual Heat Removal System RWCU - Reactor Water Cle'a'n Up System I
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g: Res. Nati Resistant material a t Non-Res. Matl - Non-resistant material 7, -s. Explanations: oi-
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Welds-listed as non-resistant: Nozzle to safe end welds (contain Inconel 182) n, . Safe end extension to safe end welds'(contain Inconel 182) U* < Circumferential welds with non-resistant stainless steel in one or more oft upstream component,' downstream component.: and. weld, metal, ,
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- .It many be-also.be noted that the'statene,ts pertaining - -
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- the nozzle + assemblies in Illinois Power Submittal No.'1 are .
confirmed by the listing of materials summarised in Table 2-- !
, ~(based on the detailed listing in Illinois Power. Submittal- ]
. b, No. 2).. -
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2.3.l. Hydronen Water Treatment
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. Illinois Power has prepared a plant modification in order-a; j
f , ito perform HWC pre-implementation testing. . 4 [ f; , j
;. 2.3.5 Previous Inspection Pronram
? The Illinois Power Submittal No. 1~does-not disclose their previous inspection schedule or results. However, Illinois' q m
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.. Power Submittal No. 2 contains a weld-by-weld listing of -1 previous and planned inspections.- This information is ,
f, summarized in. Table 3. - 'I y g . Note that none of the IGSCC Category D welds was inspected <
.l during Refueling Outage No. 1.:'Five of the Recirculation- !
1 System welds were inspect'ed during: Refueling Outage No.~-1,
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- p. 1 and none of the other IGSCC. Category A welds was inspected j during that outage. Jf the five Recirculation System welds-
- that were inspected, four of these had been solution':reated?
or~ treated with CRC. The other'had not received any aitigating treatment. .c ,44,. Discussion of future' inspection plans is defereed to Section I 2.5 of'this report. J 2.3.6 Evaluation and Recommendations s Illinois Power has incorrectly classified several of the welds. I l
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,3 -) ,y Past and Plannoi Inspection Schedules. -
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- . p I. No' of Inspections Performed / Scheduled
-IGSCC No. of ?a t- Future
. Systes ih Welds 1 E RFf3 M M M E 3 Noz/SE .A, .10 .4- 2 4 Nos/SE: D; 1 28 128 28- 28 1
xRecire. A- 123 , 5 12 4 -4 -5 6 .7 . :l y RHR-' .A 4 1- 1 w RWCll: A 8 1 1- 2- 1 7 1
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' Requirements of Generic Letter 88-01 H
IGSCC Category A: 25%' every 10 years (at least 12% in 6 years). ?
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1 i y~ l n IGSOC Category D .All every 2 refuelfog cycles. 1 1
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' The 50' IGSCC Category A welds which,' according to" the111st '
of welds Illinois Power' Submitital No. 2, contain non-resistant h material and have not received mitigating treatments-do not'
-- qualify for classifications as IGSCC Category A velds.< Rather,:
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-they should'be classified as either IGSOC Category D or IGSOC-yf Category G welds, depending on their. inspecti.on history.
O Specifically, it is recommended that the one weld of-that
; group that was inspected during Refueling Outage No. I should-be reclassified as an IGSCC Category D weld, and the 77 welds
'in that group that have not been inspected'should be
' reclassified-as IGSCC Category G welds.
'In addition,-the 28 welds,in nozzle assemblies that contain' Incenel 182 are incorrectly. classified. Since these welds have not been inspected (a requirement for'IGSCC_ Category-D welds, according to Generic Letter 88-01), they should_have;
.been classified as IGSCC Category G. However, since (as. i
" : discussed in Section 2.5-of this report) these welds'are all scheduled *or inspection during the next' refueling outage, it is recosaended that the cb ==4fications should not be'
- changed unless flaws are ,found during 0%se inspections.
Y 2.4 Current Plans for Mitimatina Actions'- 2.4.1 Hydronen Water Chemistry Illinois Power Submittal No. 1' states: W " Hydrogen Water Chemistry: IP plans to use a Hydrogen Water Chemistry (HWC) system at CPS. A plant modification a " has been prepared to perform the HWC pre-implementation
.. test. This test is scheduled for August to September, f; 1988. Based on the results of the HWC test, the final
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design.and installation ofla HWC system are expected toi ,
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'be initiated.in 1989 and completed'in 1990."
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2.4.2 Etress Imorovement lD ' i i
,t' Illinois Power Submittal No.~1 statess' ,
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" Stress Improvement'(SI): Twenty-four'(24) nozzle assemblies have Inconel buttering.at .their safe-end s
, connections and'are' potential candidates for stress ;f
' t-improvement.- -Industry l axperience with SI is relatively ,
1
.recent. As mentioned before,' IP plans to use a HWC system ;
, i ist. CPS, -and its installation may mitigate IGSOC on these i
r 4 nozzle assemblies." I J 2.4.3' Evaluation-and Recommendations . t 2
!Since a large portion of the piping is constructed with .i, corrosion resistant materials,f and installation of a HWC system 9
,aI .is scheduled, acceptance of the position of Illinois Power. g pertaining'to mitigating actions for Clinton is recommended, a j 7provided that-the inspection schedules are readjusted (as J
- On ; discussed in section 2.5).for the welds incorrectly classified- l as IGSOC Category A. '
L l 2.5 Current Inspection Pronram=
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3 1-L' ' 2'.5.1 Inspection Sche'dules 0- .a L :j, + J n H Illinois Power Submittal No. I describes their position as : l; follows: t 1 y , i "The extent and frequency of examination of the piping j
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., 7 . , f ki-l 't welds will bel$a accordance with the requirements'in~ASME l g4, 4 ..
Section II, 1908 Edition;through Winter 1981= Addenda. . . 1 ,
'The specific welds'to be examined will be selected-based on considerations of stress' level, piping and support- # 1 E ~
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. configurations,.and weld detail." . ,.
,jU' "'!he extent and frequency. of examination cf items in this
'i, category will be' in accordance with' Generic Intter 88 41. .
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It should.be'noted'that surface examinations'of'these o, .
.. nozzle' assemblies will be performsd at the frequency- j specified'by1the ASME Code."'
A As indicated previously, future. inspection schedules, provided'
' .in Illinois Power Submittal No. 2, are summarized in Table -l l
3 of this report. That table also contains the inspection l
"> requirements for IGSCC Category A1and IGSOC Category D welds -
I:
- as delineated)in Generic Letter 88-01. Note'that planned .
I
/ s ' inspection schedules satisfy the.NRC Staff requirements. .'
However, recall 50 - of the velds classifie'd as.IGS00 Category A welds are incorrectly classified and-should.be classified Adjustments to the
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'as IGSCC Category D or.ICS00, Category G. -
inspection schedules should accompany-these reclassificatig, ! . -l y .I 2.5.2' Inaccessible Welds j h '
, d' . Illinois Power Submittal No. 2 contains the following q *, statements pl%
h,w "All welds;are accessible to perform UT examination." i: ? fi;{. t[ ' 7 , Jj 2.5.3 Methods and Personnel i o; j y y ty: , + 7: M Illinois Power Submittal No. 2 contains the following statements concerning inspection methods and personnel [:+ 13 9 1 1 dk. .h b <, p:
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- 4 L! (1111aois Power Sunnittal No.L1 contains a similar' statements) 1 4-;
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- which explain the provision applied.to thisiitant :.
L y ."The detailed procedures,~ the equipment, and the-R -j). e' examination personne1'(Lever II or:III).used in examining I m austenitic stainless stee1~ component welds and sustenitic .: ' stainless steel component welds.with overlays, where' ,
+ 1 1,
applicable, are those qualified by a formal program in j g accordance with the Nondestructive Examination (NDE). ij Coordination Plan agreed upon by MRC, Electric Power 4 Ll . , Research Institute (EPRI), and the BWR Owners Group forf , C IGSCC research, as implemented at the EPRI'NDE center j t. 4 in Charlotter ?,.f @ Carolina. It should be noted that. j
; none of the ettAda it CPS are currently overlaid." '
"On sustenit') ' stainless' steel' component welds'with Corrosion Resistant Cladding 1(CRC) and Reactor Pressure '
L Vessel.(RPV). nozzle acsemblies'with Inconel 182 buttering, ' L i- -
!the above mentioned EPRI qualified' procedures, equipment ]
q and examination personnel v111, demonstrate the capabilities V , to detect IGSCC on CRC on'these welds' utilizing modified r- , l-l i versions for.the above. mentioned procedures." l l% m
.I
" Level I examiners who may become qualified by demonstrating field performance capability will not be 3
utilized in thefexamination-of. piping susceptible to j IGSCC."
+
e
) '
, . . , 12.,5.4 Sample Expansion- O gp , Illinois Power Submittel No. I contains the following
. statements: *
] ,
"If one or more cracked welds in the IGSCC Category A-
=,. e
-. 14
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3
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' i ' I y 5 - ' 8 '
, 8__ ___,.______'____,___._____.______________.___.___________
w-- , . ., _ fkl ((, ,N f . p v n *, l> fA s [I)'N..
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+ 1 welds are found by a sample _ inspection-during thel ten-
-year inspection intarval,'IP will inspect an additicaal, -
l" ' ' sample of welds.. The additional sample,of welds willi
, a-e:
,s be approziastely equal in number to those saamined in 6 !? .the original sample. This additional sample will be p
similar in distribution to the origfaal; sample, unless C it is determined that there is a technical reason to select
- a'different distribution. If cracked welds are found in this additional sample IP will" inspect all the'walds
.in IGS00. Category A."
c[,& c 7 -
' 4* : - -2.5.5 Evaluation of Inspection Schedule and Recommendation s
Illinois Power's position is that they will:confona on
, . inspection schedules, methods and personnel,~and sample
<. expansion.-- They also supplied schedules which confirm that-position.- Th'us, to the extent that the welds'are correctly.
, g. . ,
? classified, it-is recommended that Illinoiis Power's position '
should be accepted. However, as previously discussed, several [ ~
'of 'the welds-should be reclassified and the inspectica
-schedules for those~ welds should-be adjusted to satisfy the:
1 inspection requirements for welds of those classifications..
,?
2.6 Channes in the Technical Specification Concerning ISI 4 r 2'.6.1 Illinois Power's Position 4
.j Illinois Power Submittal No. 1 contains the following ' statement.
concerning a change to the Technical Specification for Clinton concerning-ISIt. -
"A change to the Technical Specification Section 4.0.5 I
will be submitted separately to incorporate the above-4 )
. 15 I
4
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N 'J . . . '.. - Q( .;f ,:.. . T s l , f .q: b ,-,*?,m' - 1 b -f . .
.NRC statf positica.'
y , J 2.6.2 Evaluation and Recommengtism .
'1: .,
'[ . Since the Illinois Power plans to submit a change-in the-L, 4
- Technical Specification concerning ISI, tentative acceptance:
os [' of the Illinois Power position (pending actual receipt of
.t he c ange)'is h recommended.; 'e 4
e 2.7 Confirmation of Led Detection in Technical Specification
.i >
2.7.'1 Illinois Power's Position Y Table 4.- prepared iroe a et eilar table in Illinois Power. Submittal No. 2, and the following statements from that submittal summarise their position on leaka8e detection.
- M Concerninn Ites 1 in Table 4
, "The bases for the Clinton Technical Specifications (specifically) for TS'3/4.4.3.1, Leakage Detection Systems',
note that the ' leakage detection' systems are consistent with the recommendations of Regulatory Guide 1.45. More specifically, the leakage detection-systems at Clinton; are in compliance with Regulatory Guide:1.45 except as noted in Sections 1.8 and 5.2.4.10 of the Clinton Updated
' Safety Analysis Report (USAR). With respect to the floor
, drain sump flow monitoring system, the sensitivity, accuracy, alarm capability and all other. requirements s3 stated in Position C are met (except, as noted in USAR Section 1.8, for paragraphs C.6'and C.8 which respectively concern seismic qualification and testability). IP is currently preparing a revision to the USAR to clarify 16 l
\
, . - ~ ~ . . - _ _ _ . - ... . - _ . - _
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,[:<?'b y; E Table'4
. 1 i '
Licensee Positions on. Leakage Detection (a) 1., .
' 1
'[ Already 15 will be Alternate 'j
,:' Contained Changed Position )
to Include- Pronosed Position in TS j
- 1. Conforms with Position C of yes(*) - -
1 _ Regulatory Guide 1.45' j 7 I y, .- 2.. Plant shutdown'should be initiated when ,
'J 8 (a) within any period of 24 hours - - yes(*) -1 or less an-increase is
-indicated-in the rate of.
. ; unidentified leakage in excess'of.2 spa, or-o-
4.c , g'
' (b) the' total unidentified leakage yes - -
' +sttains a rate of 5 spa. ,
I ' 3.; Leakage monitored at four hour yes(a) . intervals or less..
,' a jf ' 4. Unidentified leakage' includes all j except u 1
, + > ,
- (a)Lleakage into closed systems, yes - - l 1
- or
, .(b) leakag'.into e the containment yes - -
LL atmosphere from sources that i are located,:do not interfere .
" with monitoring systems, or not.from throughwall crack.
51 Provisions.for' shutdown within 24 yes(*) ' r._ ,a, hours due to' inoperable measurement ; L instruments-in pirnts' with Category ; b 4
, D, E, F, or G welds.
i
. (a) See text for notes.
7
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5 f~ the cap,'ilities and limitations' of the dryvell gaseous and particulate radioactivity monitors. A reference to j ISA/ ANSI S67.03 vill be' incorporated since the limited j h% 3; capability of radioactivity monitors.to provide an accurate a 4f c y a.. _ leakage rate (equivalent.to a particular rate in spa)~ . 1
; t is acknowledged in Position C.5 for.these monitors. -(Note; j Y , Radioactivity. monitors are not addressed in Generic Intter
88-41 but, as part of the leak detection system,- they can be'used to qualitatively assess or characterise' leakage' j
;, and provide backup information or means to assess' the '
response'of other leak detection instrumentation, including. those which' detect or' indicate UNIDENTIFIED LF.AKAGE)."- . [ 1 Concernina Iter 2(a) in Table 4 ,l l
- "This limit.(2 gps within a 24-hour period or less) is -
currently being incorporated into the LCO statement of '; j
- CPS Technical Specification 3.4.3.2 (Operational
- Leakage).
T
.. (
- The ACTION to be required (when the limit has beer.
, exceeded) will,'.however, permit some time (up to 4 hours
- from the time of. discovery) to identify the source ~as not service sensitive Type 304 or 316 austenitic stainless- 3
- steel. 'Then if it cannot be determined that the limakage is from a source definitely not associated with such stainless' steel, plant shutdown must be initiated."
V c - Concernina Item 3 of Table 4 - k
, t i
+< , '"By the Technical Specification changes to be proposed, '
' "l , UNIDENTIFIED LEAKAGE will not normally be discreetly
[ monitored (under the Surveillance Requirements) at 4-hour intervals or less due to credit taken for the continuous- 1 3( type monitoring system (V-notched weir bor design with '
, alara capability) employed at Clinton. Generic Letter 4,.
- 18 5 ,
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.88-01 recosasaded.that sump level should.be monitored' j at 4-hour intervals or less for sump level monitoring; h.m-
' system utilizing L'fimed eassureaant-interval'. methods.
4
- Although the sys' ~ heign employed at Clinton for
!I '
determining the uniaentified. leakage is. includes an alternative means.utilising ' fined-asasurement-interval'-
. methods (i.e., sump pump-out timersi etc.), these alternative means of verifying unidentified leakage are considered to be a backup means and not the primary or ]
j normal means. IP believes lthat the primary system or means for verifying unidentified-leakage'(i.e., the
~ continuous-type monitoring system) does not constitute a system' utilizing a ' fined-maaaureaant-interval' method.
' J Therafore, the 12 hour surveillance interval currently.
7 a- , specified in the CPS Technical Specification Surveillance-
= Requirement for monitoring drywell floor drain sump flow.
i, 'would remain unchanged. However, if the weir bos V-notch ',e level indication or alara becomes unavailable'se that-the UNIDENTIFIED LEAKAGE rate must be determined'by the
~ alternative' method (calculating an average flow based
+
on the sump pump-out rate). the -new ACTION statement -
, currentlybeingprop$ sed)wouldbeentered. Monitoring 4
.the sump flow while operating under the provision of the
'@ .L proposed ACTION statement would 3hgt b e required at least once per 4 hours. This is discussed more (in the note)
I i# > below." 7 m Concerninn Item 5-in Table 5 L "This ites, which is Point (3) in the Generic I4tter,
% suggests that the out-of-service time allowed for i inoperable sump flow monitoring instruments should be limited to 24 hours before a plant shutdown is required.
] IP concurs with this position if the inoperable o ,
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qu , w, iinstrumentation.would not permit a determination of the 7 f; x ' M p- /t UNIDENTIFIED (or. IDENTIFID) LEAKAGE). However, if the
, .?- plant _ design includes redundant means for' determining.
. ' 1; the UNIDENTIFIED (or IDENTIFIED) LEAKAGE, then" w
~
consideration should be given to allowing.a longer y out-of-service' time for the instrumentation." l "By the proposed Technical Specification changes to be' s submitted.in a forthcoming proposed license amendment,
< a revised. ACTION statement would.be provided under CPS l' Technical Specification 3.A.3.1 (Leakage Detection 4 Systems). The proposed ACTION would permit certain' leakage detection instruments to be inoperable for up to 30' days ]
'a-- if;there are alternative means to determine the applicable 1
- I leakage rate'and the rate.is monitored at'the specified; y I '
frequency). For UNIDENTIFIED LEAKAGE, the frequency ts ' at'least'once.per 4 hours as noted'above). Otherwise, . ( 4 the plant must be shut down. The 30' days is based on o the ACTION statement that was originally specified-in- 'l the Standard Technical Specifications. The proposed 7 changes to the corresponding ACTION statement of the. CPS' , Technical'Pp0Cification'would Clarify when and under what conditions a 30-day , allowed .out-of-service time is t , m permitted (and to require increased monitoring of the, .?a drywell floor drain sump flow when the:' primary' sump- g flow indication is unavailable)." j
, )
,k ' 2.7.2 Evaluation and Recommendations (? a Y IW s The Technical Specifications on leakage detection are in l conformance with the NRC Staff position on total unidentified E leakage and on the definition of unidentified leakage. Thus 1 acceptance-of these items in 11: Sois Power's position is recommended. s
- 20
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Concernina Conforasnee with Reaulatory Guide'1!45 7 acceptance. N 'of Illinois Power's' position is recommended:since the-I . , u; , Ia-- deviations'from conformance are documented'in previous safety;
;M Lanalyses reports and a revision:is being ma'e to clarify:
~
> d
;]if' capabilities of drywell gaseous and, particulate.-adioactivity-
- ', ?.' monitors which can be used to assess the re'aponse of other
.qN leak detection instirunentation.- , e Concernina~an Increase'in Rate of dnidentified Leakanes an 3; , amendment to the Technical Specification is planned that will-n . . bring'it into conformance with the NRC. Staff position except
' for a deviation which 'would' allow a period of = 4 hours for'
< determining whether or not.the source of unidentified leakage-is associated with the austenitic piping system. Although. < 4
- this is less restrictive than the NRC Staff position,'it.does
, t 'not poseja significant safety hazard, so acceptance of Illinois m '
Power's position on this item is-recommended. . [ ' Concerninn Frecuency of-Leakane Monitorinat even though the primary leakage monitoring system provides continuous monitoring,.the leakage should be determined from flow-measurements at approxima'tely 4 hour intervals (rather than-
~
12 hour intervals as presently requiredtat Clinton). Thus. K ,
>a' change to the Technical Specification'to this effect should=
n'
.U be made.
Concernina Inoperable Monitorina Instruments: acceptance of y , , Illinois Power's position-on provisions for shutdown is Nf , recommended.;provided.that alternate methods of. monitoring
\ . leakage are invoked as described in the event of inoperability
'h ,
of normal measuring methods. o ,
, 21 f
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2.8' Plans for Notification of NRC'of Plans' e xn1 j y f.{ ; s 2.8.1' Illinois Power Submittal No. l'contains the followinn d
.m . statement:-
A
;f g+
"Fisws' detected during the examination' of components Mh '
covered by Generic Letter 88-01 will be categorised with . J e j regard to location, size,-and orientation. These flaws j i 'will be evaluated for acceptance'in accordance with the ' ASME Section II, 1980 Edition through Winter 1981= Addenda., d Any. flaws which exceed the acceptance criteria which is. --T j r listed'in the ASME Section II,1980 Edition with Addenda -e :j through Winter'1981, will be evaluated for continued ! service in accordance with IWB-3600 of the ASME:Section. II, 1986 Edition. Flaws which exceed the acceptance criteria which is listed'in the ASME Section II, 1980: Edition with Addenda through Winter 1981, changes found ., in the condition of welds previously known to'belcracked, 'J evaluations of flaws for continued operation, and repair
. plans for cracked weldsents will be submitted for NRC g approval prior to resumption of. operation." l 1
/ 12.8.2 Evaluation and Recommendation < :
Illinois Power's position on-plans for notification of the .t 9 NRC:of. flaws conform with the NRC' Staff position, so acceptance of Illinois Power's position is recommended. r
- 3. ALTERNATIVE POSITIONS AND REQUEST FOR RELIEF a
-,.M4 Relief. requests -(designated as " Illinois Power, Clinton Power Station - .:
-Section XI Relief Request' Numbers 4001, 4003, and 4004" were contained I in an attachment to the Illinois Power submittal. These requests were r
, . 22 g*- ,
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p . s. , , ; y. Y,. jhkw l 1 mg { : .n ; 3X , v .
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- only pertinent to inspections that are outside,of-the scope lof Generic
~~
pn: h' , L15tter 88-01 for/the following-reasons. # ;
+
l(1) Relief' Request Number'4001 pertains to inspections of lines, ;
- }* --
that are not'arposed'to reactor coolant during operation.- y (2) Relief Request Number'4003 pertains to visual inspections'of . - ; componont supports.- w
-(3) Relief. Request Number 4004 pertains to visual inspections of. [
hydraulic and mechanical snubbers. ,
.g -
-t 4. 00NCLUSIONS AND RECO M ENDATIONS j Illinois Power.has indicated that they endorse and accept all.of the >
thirteen NRC Staff positions outlined in Generic Letter.88-01 with ; certain' provisions.; Provisions were attached-to the item concerning- i Inspection Methods and Personnel and Leakage Detection.- ')
, 1 1
a Concerning. Illinois Power provision on inspection methods: Illinois j
= Power intends to' extend the approved inspection methods:to cover welds
~
1 y that have been clad'with corrosion resistant cladding. Provisions were attached to the item on leakage detection concerning frequency of leakage monitoring and operability of monitoring << instruments.- Since they use continuous monitoring rather than fixed- i measurement-interval methods,Lthey record the results'only on a 12 hour ; Mi basis,rather than every four hours. They should'still determine the-leakage. rate at approximately four hour intervals or less. Another
% provision is added to the requirement for plant shutdown when the leakage' '
' rate exceeds ~2 spa. They propose to allow a four hour period to identify.
- the source of leakage before.initieting shutdown rather than initiating I
' shutdown limmediately. Finally, they propose the use of alternate methods 23 9 ,
1 , i*:' ' ' -
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, l 6*'
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1 ^ I monitoring leakage for~ periods of up to 30 days when normal monitoring l [ instruments become inoperable'. Even though the latter two provisions.
' ~
are deviations for the NRC Staff position, they. provide adequate' > 6 '
-,, assurance of meeting the intent of the NRC Staff position.
'._., Illinois Power has performed extensive mitigating actions at Clinton
. consisting'of design and construction changes, piping replacement, ,
Lj solution heat treating, and weld cladding. Illinois Power classified' I
. . r Wk 28: welds in nozzle assemblies as IGSCC D because they contain1
\ non-resistant nickel; alloys, and they classified a11' piping welds are 1 IGSCC Category A welds. ~However, conflicting information was provided con'cerning 50 of the :IGSCC Category A welds. I.'.linois Power Submittal- .j 0 . No. 1 states that all non-resistant materials,were either changed to l l 1. i .
- e. resistant' materials in these welds'or that they were mitigated with J either solution heat treating or corrosion resistant cladding.- Illinois ,
L* Power Submittal No'.-2 shows that-78 of the welds remain with' non-resistant material and unmittigated. 'd ' i .- I
- A Hydrogen Water Chemistry system is planned and expected to be operational in 1990. Otherwise', no additional sitigating' actions are l planned.- , q l
l Illinois Power's position on inspection is in conformance with the NRC ,
-l g ; Staff, and planned schedules: satisfy requirements of Generic Letter j
88-01 except for the' welds that have been impropeily classified.as IGSCC
.l l< Category A welds. Schedules should be adjusted for these welds. -)
l
-'l *
' Illinois Power plans separate submissions changing the Technical q
# x Specifications, pertaining to ISI and leakage detection for Clinton that
'J will comply with NRC Staff positions on schedules, methods and personnel 4 4'
(with the provision concerning welds with CRC), and sample expansion 4 , -as delir.cated in Generic latter 88-01.
;h .
a a, Based on the above evaluation, the following recommendations are made L ., ] ? [ l l ', , . L, - 24 L q
+ '
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R
" 9
[3,gl j .* [' , (1)LRejection of Illinois Power's classification of.50Twelds that - -) .sc , lcontain non-resistant materials end have not been mitigated.- ; Theclassifications'ofthese(welds'shouldbechanged.toIGSOC ,
; ,7 Categories D and G, depending on-their inspection-histories. !
<I !
-(2)' Acceptance of the IGSCC classifications'of the other welds.
P y. '
+
.(3)LApproval of. inspection plans for ClintonLfor the welds that-were;given correct IGSOC classifications.- -Adjustments'should.
be made'with the inspection schedules of the other welds to i '
.)
comply with the NRC Staff positions for the new IGSCC classifications.- " l i 1 i. (4) ' Tentative acceptance of ' Illinois. Power's position on amending -
.I tthe Technical Specification on ISI, pending actual: receipt of '!
the proposed amendment that has been promised in a. separate. L ..[, .
. submittal.
1
~
(5) Rejection of Illinois Power's position regarding frequency of 7 determiningtleakage rates. They should-amend their Technical' I Specification ~to require determinations at approximately four hour intervals or less. * - i q
-(6);AcceptanceLof'other portions of Illinois Power's position,
.concerning leakage detection. '
; 4." ,
-(7) Acceptance of other' portions of Illinois Power's Submittals.
t
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- 5. REFERENCES s y,
- p y -
< * '1. " Technical report on Material Selection and Processing Guidelines 1"'
- for;BWR Coolant Pressure Boundary Piping," NUREG 0313.. Redpion.
p fp[ ~ 2, U.S. Nuclear Regulatory Commission, Office of. Nuclear Re$c3 y ;]Q j ;( Regulation,' January,:1988.
~
@,b q 4 ,. 2'. " Investigation and Evaluation of Stress-Corrosion CraeHas in Piping
- i i4"! '
of Light Water Reactor Plants," NUREG 0531, U. S. Nuclear, Regulator y. Y Commission, February,'1979. .t- :i
- y a i
)
l . i *
'3.< "NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping,"'
u.-) ,
, Generic' Letter 88-01, U.S. Nuclear Regulatory Commission,-January w :
\ D .; 25, 1988.: >
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