ML20217A344
| ML20217A344 | |
| Person / Time | |
|---|---|
| Issue date: | 03/19/1998 |
| From: | Craig C NRC (Affiliation Not Assigned) |
| To: | Newton R WESTINGHOUSE OPERATING PLANTS OWNERS GROUP, WISCONSIN ELECTRIC POWER CO. |
| References | |
| PROJECT-694 NUDOCS 9803250002 | |
| Download: ML20217A344 (18) | |
Text
.j March 19, 1998 Mr. Roger A. Newton, Chairman Regulatory Response Group Westinghouse Owners Group Wisconsin Electric Power Company 231 West Michigan Milwaukee, WI 53201
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (RAl) RELATED TO THE PART-LENGTH CONTROL ROD DRIVE MECHANISM (CRDM) HOUSING ISSUE
Dear Mr. Newton:
By letter dated March 6,1998, the Westinghouse Owners Group (WOG) provided information regarding the assessment of the part-length CRDM housing issue and the WOG's planned act 'ities to resolve the potential generic concems. The staff has reviewed the information and has determined that it needs additional information in order to complete its review. The staff's questions are enclosed.
To ensure timely resolution of the short-term Regulatory Response Group issues, the staff requests a response within 30 days of receipt of this letter.
Sincerely, Original Signed By:
Claudia M. Craig, Senior Project Manager Generic issues and Environmental Projects Branch Division of Reactor Program Management
)
Office of Nuclear Reactor Regulation
/
Project No. 694
Enclosure:
As stated
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March 19, 1998 Mr. Roger A. Newton, Chairman Regu'.atory Response Group Westinghouse Owners Group Wisconsin Electric Power Company 231 West Michigan Milwaukee,WI 53201
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (RAI) RELATED TO THE PART-LENGTH CONTROL ROD DRIVE MECHANISM (CRDM) HOUSING ISSUE
Dear Mr. Newton:
By letter dated March 6,1998, the Westinghouse Owners Group (WOG) provided information regarding the assessment of the part-length CRDM housing issue and the WOG's planned activities to resolve the potential generic concems. The staff has reviewed the information and has determined that it needs additional information in order to complete its review. The staffs questions are enclosed.
To ensure timely resolution of the short-term Regulatory Response Group issues, the staff requests a response within 30 days of receipt of this letter.
Sincerely,
\\ )(Ltdto M,
( l&MC Claudia M. Craig, Senior Project Manag@
Generic Issues and Environmental Projects Branch Division of Reactor Program Management Office of Nuclear Reactor Regulation Project No. 694
Enclosure:
As stated cc w/ encl: See next page
, j QUESTIONS 1,
in the March 6,1998, WOG letter, the RRG suggested WOG members " Perform additional records search to better identify appbability and obtain other data to confirm the absence of any cracking" as an option that might be incorporated in a member's plan to address this issue. In the meeting scheduled for March 23,1998, the following has been included as an agenda item to develop details of a potentialintegrated plan:
" Perform additional records search to identify details regarding welds, materials and CRDM design changes." The staff understands how the second item could be useful in identifying information that demonstrates the uniqueness of the Prairie Island crack.
However, it is not clear what information supports this option as part of an individual member's plan based on the information currently available. Please clarify how this option would be beneficial on a plant-specific basis.
2.
The RRG recommendations do not appear definitive regarding the need for either inspection or preemptive repair to alleviate the concem regarding a degraded component being in service. While the staff agrees that inspection results from other plants have not, to date, identified similar degradation and are considered encouraging with regard to addressing the issue in the longer term, in our view, sufficient information has not been presented to obviate the need for inspection or preemptive repair at each plant in the long term. Please provide your response.
3.
Are there any design or construction differences (aside from filler metal) between those welds buttered with Alloy 82 rather than 309 stainless steel (SS)? Were the construction sequences and the non-destructive examination (NDE) methods (welding, machining, NDE and PWHT) used for the Alloy 82 welded assemblies different from the 309 buttered assemblies? What were the welding process and pre and post weld heat treatment requirements?
o 4.
Are dissimilar metal welds on part length motor housings manufactured by Royal Industries using Alloy 82 instead of 309 SS considered an attemative design?
5.
In the response to Question 2(b)(3) (Attachment 1 to the WOG letter dated March 6, 1998), the WOG stated that the effects of jet thrust force from the postulated failure of a part length CRDM housing are bounded by previously analyzed postulated jets from full length CRDM housing, it is not clear what type or size of breaks (i.e., longitudinal breaks vs. circumferential breaks) were assuined in those previous studies. In addition, the WOG's response stated that the previous analysis of jet thrust forces as::umed a jet expansion of 10'. However, in the WOG/NRC meeting of February 27,1998, Westinghouse stated that the jet from a postulated full circumferential break would be directed upward and not directly impinge on adjacent full length housings. It is not clear what jet expansion model was assumed for the circumferential break jet evaluation discussed in the WOG/NRC meeting. Please describe the jet thrust force evaluations performed, including the previously postulated full length CRDM housing failure studies.
The description should include the type and the size of the breaks postulated, the jet expansion model assumed, the potential targets identified, and a discussion to show how the jet impingement load evaluation previously performed for the full length CRDM housing would envelop the worst potential jet loads from the current pnstulated failure of a part length CRDM housing.
Enclosure i#
I 2
1 ADDITIONAL COMMENT The staff notes the probabilistic analysis described in response to NRC Question 3 (Attachment i to the WOG letter dated March 6,1998) uses a value of 0.1 for the presence of a flaw in other WOG plants. This value was obtained as a per-weld probability. Based on the cited data alone, the probability for another plant with 8 of the subject welds would be 0.57 and the probability for a plant with 16 welds would be 0.81. The staff believes the ongoing inspections
- are important to provide more data and confidence in the RRG conclusion that the subject weld defect is an isolated incidence resulting from weld fabrication.
9 Enclosure s.,
m
- e cc:
Mr. Andrew P. Drake, Project Manager Westinghouse Owners Group Westinghouse Electric Corporation Mail Stop ECE 5-6 Post Office Box 355 Pitt, burgh, Pennsylvania 15230-0355 Mr. Louis F. Liberatori, Jr., Chairman Westinghouse Owners Group Consolidated Edison Co. of NY, Inc.
Indian Point, Unit 2 Broadway and Bieskley Avenue Buchanan, NY 10511 Mr. Henry A. Sepp, Managar Regulatory and Licensing Engineering Westinghouse Electric Corporation Mail Stop ECE 4-07A 1
Post Office Box 355 Pittsburgh, Pennsylvania 15230-0355 i
i
)
March 19,1998 1
Mr. Roger A. Newton, Chairman Regulatory Response Group Westinghouse Owners Group Wisconsin Electric Power Company 231 West Michigan Milwaukee,WI 53201
SUBJECT:
REQUEST FOR ADDIT!O,N_AL INFORMATION (RA!) RELATED TO THE PART-LENGTH CONTROL ROD DRIVE ME.QHANISM (CRDM) HOUSING ISSUE
Dear Mr. Newton:
By letter dated March 6,1998, the Westinghouse Owners Group (WOG) provided information regarding the assessment of the part-length CRDM housing issue and the WOG's planned activities to resolve the potential generic concerns. The staff has reviewed the information and has determined that it needs additional information in order to complete its review. The staff's questions are enclosed.
To ensure timely resolution of the short-term Regulatory Response Group issues, the staff requests a response within 30 days of receipt of this letter.
Sincerely, Original Signed By:
Claudia M. Craig, Senior Project Manager Generic issues and Environmental Projects Branch Division of Reactor Program Management Office of Nuclear Reactor Regulation Project No. 694
Enclosure:
As stated cc w/ encl: See next page DISTRIBlJTION: See attached page DOCUMENT NAME: RRGRAI.WPD OFFICE PGEB (A)SC:PGEB (A)BC:PCjEB_
(A)BC:EMCB NAME Cdrd:M MMaD TEssig h TSullivan Gh I
DATE 3 l]/98 3/IS/99 j /tB /98 O /t9 /9s" OFFICIAL RECORD COPY
~1 DISTRIBUTION Ltr. to R. Newton fm C. Craig dated March 19, 1998 ntral FilWin -
File PUBLIC PGEB r/f JRoe/DMatthews l
Glainas/JStrosnider RWessman TSullivan RHermann KWichman GHomseth RBenedict MChatterton SLong RLi CCarpenter BWetzel TEssig MMalloy CCraig DHood
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't UNITED STATES NUCLEAR REGULATORY COMMISSION A*****/
WASHINGTON, D.C. 30e864006 March 19, 1998 Mr. Roger A. Newton, Chairman Regulatory Response Group Westinghouse Owners Group Wisconsin Electric Power Company
' 231 West Michigan Milwaukee,WI 53201
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (RAI) RELATED TO THE PART-LENGTH CONTROL ROD DRIVE MECHANISM (CRDM) HOUSING ISSUE
Dear Mr. Newton:
By letter dated March 6,1998, the Westinghouse Owners Group (WOG) provided information regarding the assessment of the part-length CRDM housing issue and the WOG's planned activities to resolve the potential generic concerns. The staff has reviewed the information and has determined that it needs additional information in order to complete its review. The staff's questions are enclosed.
To ensure timely resolution of the short-term Regulatory Response Group issues, the staff requests a response within 30 days of receipt of this letter.
Sincerely, O.LbVX
'UL G Claudia M. Craig, Senior Project Manage [
Generic issues and Environmental Projects Branch Division of Reactor Program Management Office of Nuclear Reactor Regulation Project No. 694
Enclosure:
As stated cc w/ encl: See next page i
f 1
QUESTIONS 1.
In the March 6,1998, WOG letter, the RRG suggested WOG members " Perform additional records search to better identify applicability and obtain other data to confirm l
the absence of any cracking" as an option that might be incorporated in a member's
' plan to address this issue. In the meeting scheduled for March 23,1998, the following t
has been included as an agenda item to develop details of a potential integrated plan:
" Perform additional records search to identify details regarding welds, materials and CRDM design changes." The staff understands how the second item could be useful in identifying information that demonstrates the uniqueness of the Prairie Island crack.
However, it is not clear what information supports this option as part of an individual member's plan based on the information currently available. Please clarify how,this option would be beneficial on a plant-specific basis.
2.
The RRG recommendations do not appear definitive regarding the need for either inspection or preemptive repair to alleviate the concem regarding a degraded component being in service. While the staff agrees that inspection results from other plants have not, to date, identified similar degradation and are considered encouraging with regard to addressing the issue in the longer term, in our view, sufficient information has not been presented to obviate the need for inspection or preemptive repair at each plant in the long term. Please provide your response.
3.
Are there any design or construction differences (aside from filler metal) between those welds buttered with Alloy 82 rather than 309 stainless steel (SS)? Were the construction sequences and the non-destructive examination (NDE) methods (welding, machining, NDE and PWHT) used for the Alloy 82 welded assemblies different from the 309 buttered assemblies? What were the welding process and pre and post weld heat treatment requirements?
4.
Are dissimilar metal welds on part length motor housings manufactured by Royal industries using Alloy 82 instead of 309 SS considered an attemative design?
5.
In the response to Question 2(b)(3) (Attachment 1 to the WOG letter dated March 6, 1998), the WOG stated that the effects of jet thrust force from the postulated failure of a part length CRDM housing are bounded by previously analyzed postulated jets from full length CRDM housing, it is not clear what type or size of breaks (i.e., longitudinal breaks vs. circumferential breaks) were assumed in those previous studies. In addition, the WOG's response stated that the previous analysis of jet thrust forces assumed a jet expansion of 10'. However, in the WOG/NRC meeting of February 27,1998, Westinghouse stated that the jet from a postulated full circumferential break would be directed upward and not directly impinge on adjacent full length housings. It is not clear what jet expansion model was assumed for the circumferential break jet evaluation discussed in the WOGiNRC meeting. Please describe the jet thrust force evaluations performed, including the previously postulated full length CRDM housing failure studies.
The description should include the type and the size of the breaks postulated, the jet expansion model assumed, the potential targets identified, and a discussion to show how the jet impingement load evaluation previously performed for the full length CRDM housing would envelop the worst potentialjet loads from the current postulated failure of a part length CRDM housing.
Enclosure
,O
,t 2
ADDITIONAL COMMENT
]
The staff notes the probabilistic analysis described in response to NRC Question 3 (Attachment 1 to the WOG letter dated March 6,1998) uses a value of 0.1 for the presence of a flaw in other WOG plants. This value was obtained as a per-weld probability. Based on the cited data alone, the probability for another plant with 8 of the subject welds would be 0.57 and the probability for a plant with 16 welds would be 0.81. The staff believes the ongoing inspections are important to provide more data and confidence in the RRG conclusion that the subject weld defect is an isolated incidence resulting from weld fabrication.
l 4.w Enclosure
I J
i
,L CC:
Mr. Andrew P. Drake, Project Manager Westinghouse Owners Group Westinghouse Electric Corporation 4
Mail Stop ECE 5-6 Post Office Box 355 Pittsburgh, Pennsylvania 15230 '1355 Mr. Louis F. Liberatori, Jr., Chairman Westinghouse Owners Group Consolidated Edison Co. of NY, Inc.
Indian Point, Unit 2 Broadway and Bleakley Avenue Buchanan, NY 10511 j
Mr. Henry A. Sepp, Manager Regulatory and Licensing Engineering Westinghouse Electric Corporation Mail Stop ECE 4-07A i
Post Office Box 355 Pittsburgh, Pennsylvania 15230-0355
\\
March 19, 1998
>-4 Mr. Roger A. Newton, Chairman Regulatory Response Group Westinghouse Owners Group Wisconsin Electric Power Company 231 West Michigan Milwaukee,WI 53201
SUBJECT:
REQUEST FOR ADDITIONAL IMFORMATION (RAI) RELATED TO THE PART-LENGTH CONTROL ROD DRIVE MECHANISM (CRDM) HOUSlHG ISSUE
Dear Mr. Newton:
By letter dated March 6,1998, the Westinghouse Owners Group (WOG) provided information regarding the assessment of the part-length CRDM housing issue and the WOG's planned activities to resolve the potential generic concems. The sta# has reviewed the information and has determined that it needs additional information in order to complete its review. The staffs questions are enclose (1 To ensure timely resolution of the short-term Regulatory Response Group issues, the sta#
requests a response within 30 days of receipt of this letter.
Sincerely, Original Signed By:
Claudia M. Craig, Senior Project Manager Generic Issues and Environmental Projects Branch Division of Reactor Program Management ONice of Nuclear Reactor Regulation Project No. 694
Enclosure:
As stated cc w/ encl See next page DISTRIBUTION. See attached page DOCUMENT NAME: RRGRAl.WPD OFFICE PGEB (A)SC:PGEB (A)BC:PrfEB (A)BC:EMCB NAME Cdrak:M MYaD TEssig h TSullivan h l
DATE 3 l]/98 3 / Isf /98 3/18/98' D/\\9/98 OFFICIAL RECORD COPY
/
DISTRIBUTION Ltr. to R. Newton fm C. Craig dated _Mgrch 19, 1998 Central Files Project File WC PGEB r/f JRoe/DMatthews GLainas/JStrosnider RWessman TSullivan RHermann KWichman GHomseth RBenedict MChatterton SLong RLi CCarpenter BWetzel TEssig MMalloy CCraig DHood
'?
=
p reg UNITED STATES i
g 4
'l g
j NUCLEAR REGULATORY COMMISSION a
f WASHINGTON, D.C. 3065H001
- p$
March 19, 1998 l
Mr. Roger A. Newton, Chairman i
Regulatory Response Group Westinghouse Owners Group Wisconsin Electric Power Company f
231 West Michigan Milwaukee, WI 53201
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (RAl) RELATED TO THE PART-LENGTH CONTROL ROD DRIVE MECHANISM (CRDM) HOUSING ISSUE
Dear Mr. Newton:
j By letter dated March 6,1998, the Westinghouse Owners Group (WOG) provided information regarding the assessment of the part-length CRDM housing issue and the WOG's planned activities to resolve the potential generic concerns. The staff has reviewed the information and has determined that it needs additional Information in order to complete its review. The staff's questions are enclosed.
To ensure timely resolution of the short-term Regulatory Response Group issues, the staff requests a response within 30 days of receipt of this letter.
Sincerely,
\\
r r
\\
b
& N.
Oh Claudia M. Craig, Senior Project Manag@
Generic issues and Environmental l
Projects Branch Division of Reactor Program Management Office of Nuclear Reactor Regulation l
Project No. 694
Enclosure:
As stated i
cc w/ encl: See next page i
1 i
t a d
QUESTIONS 1.
In the March 6,1998, WOG letter, the RRG suggested WOG members " Perform additional records search to better identify applicability and obtain other data to confirm the absence of any cracking" as an option that might be incorporated in a member's l
plan to address this issue. In the meeting scheduled for March 23,1998, the following has been included as an agenda item to develop details of a potential integrated plan:
" Perform additional records search to identify details regarding welds, materials and CRDM design changes." The staff understands how the second item could be usefulin identifying information that demonstrates the uniqueness of the Prairie Island crack.
However, it is not clear what information supports this option as part of an individual member's plan based on the information currently available. Please clarify how this option would be beneficial on a plant-specific basis.
2.
The RRG recommendations do not appear definitive regarding the need for either inspection or preemptive repair to alleviate the concem regarding a degraded component being in service. While the staff agrees that inspection results from other plants have not, to date. identified similar degradation and are considered encouraging with regard to addressing the issue in the longer term, in our view, sufficient information has not been presented to obviate the need for inspection or preemptive repair at each plant in the long term. Please provide your response.
3.
Are there any design or construction differences (aside from filler metal) between those welds buttered with Alloy 82 rather than 309 stainless steel (SS)? Were the construction saquences and the non-destructive examination (NDE) methods (welding, machining, NDE and PWHT) used for the Alloy 82 welded assemblies different from the 309 buttered assemblies? What were the welding process and pre and post weld heat treatment requirements?
4.
Are dissimilar metal welds on part length motor housings manufactured by Royal Industries using Alloy 82 instead of 309 SS considered an attemative design?
5.
In the response to Question 2(b)(3) (Attachment 1 to the WOG letter dated March 6, 1998), the WOG stated that the effects of jet thrust force from the postulated failure of a part length CRDM housing are bounded by previously analyzed postulated jets from full length CRDM housing. It is not clear what type or size of breaks (i.e., longitudinal breaks vs. circumferential breaks) were assumed in those previous studies. In addition, the WOG's response stated that the previous analysis of jet thrust forces assumed a jet expansion of 10*. However, in the WOG/NRC meeting of February 27,1998, Westinghouse stated that the jet from a postulated full circumferential break would be directed upward and not directly impinge on adjacent full length housings. It is not clear what jet expansion model was assumed for the circumferential break jet evaluation discussed in the WOGINRC meeting. Please describe the jet thrust force evaluations performed, including the previously postulated full length CRDM housing failure studies.
The description should include the type and the size of the breaks postulated, the jet expansion model assumed, the potential targets identified, and a discussion to show how the jet impingement load evaluation previously performed for the full length CRDM housing would envelop the worst potential jet loads from the current postulated failure of a part length CRDM housing.
Enclosure
l
- i 1
2 ADDITIONAL COMMENT The staff notes the probabilistic analysis described in response to NRC Question 3 (Attachment 1 to the WOG letter dated March 6,1998) uses a value of 0.1 for the presence of a flaw in other WOG plants. This value was obtained as a per-weld probability. Based on the cited data alone, the probability for another plant with 8 of the subject welds would be 0.57 and the probability for a plant with 16 welds would be 0.81. The staff believes the ongoing inspections are important to provide more data and confidence in the RRG conclusion that the subject weld defect is an isolated incidence resulting from weld fabrication.
4 Enclosure
l '(
cc:
Mr. Andrew P. Drake, Project Manager Westinghouse Owners Group Westinghouse Electric Corporation Mail Stop ECE 5-6 Post Office Box 355 Pittsburgh, Pennsylvania 15230-0355 Mr. Louis F. Liberatori, Jr., Chairman Westinghouse Owners Group l
Consolidated Edison Co. of NY, Inc.
Indian Point, Unit 2 Broadway and Bleakley Avenue Buchanan, NY 10511 Mr. Henry A. Sepp, Manager Regulatory and Licensing Engineering l
Westinghouse Electric Corporation Mail Stop ECE 4-07A Post Office Box 355 Pittsburgh, Pennsylvania 15230-0355 l
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