ML20010A855
| ML20010A855 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 08/06/1981 |
| From: | Mike Williams Office of Nuclear Reactor Regulation |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20010A856 | List: |
| References | |
| NUDOCS 8108130022 | |
| Download: ML20010A855 (11) | |
Text
~
L
+
s h*
~
p-2Q
'/
e' ly f@
AU6 6 1981
'=j
'll 9,
rg.
A MEMORANDUM TO: Thouas A. Ippolito, C Operating Reactors Branch #2, DL FROM:
Mark H. Williams, Project itanager Operating Reactors Branch #2, DL
SUBJECT:
MEETING
SUMMARY
.. PILGRIM I CORE SPRAY HEADER CRACKS A meeting was held with the Boston Edison Company on July 30, 1981 to discuss the acceptability of operation through cycle 6 with cracks in the core spr7y header.
Amendment 50, 42 to License No. DPR-35 contained the original Safety Evaluation regarding the acceptability of the operation of Pilgrim I with cracklike indications on the Core Spray Header. These indications were discovered during the ten year ISI (Feb.1980).
In the Amendment flo. 42 Safe,ty Evaluation it was determined that the operation for one cycle (Cycle 5) was acceptable.
The Licensee has recently completed a review of the potential for further degraded conditions to develop during cycle 6 operations. This was done through contracts with Teledyne and Aptech Engineering Services. As a result of this review, Boston Edison has determined that adequate assurance of safe operation can be provided through Cycle 6.
Subsequent to a presentation by Boston Edison (Enclosure 1), it was determined that a formal submittal should be made.
The flRC staff position on this issue is that Pilgrim I was licensed with the capability to use Core Spray for accident mitigation. Even though current GE analysis may demonstrate that spray heat transfer is not necessary to meet 10 CFR 50 Appendix K, the original margins designed into the plant, which formed the basis for the license, should be retained.
In this regard, the NRC staff considers that Boston Edison should either demonstrate that the full operability of the Core Spray systen will not be degraded by the projected cracking and, if this is not possible, demonstrate their capability to keep the sparger in an operable condition. A demonstration of the retention of full Core Spray operability appears impossible since the cause of the cracking is not known, and the rate of progression of the condition can hot be adequately quantified without repeated inspections, the second of which will take place this n.
outage. Therefore, in order for the ilRC to authorize Cycle 6 operations prior to a review of all information derived from the outage BEco should justify their ability and plan to retain full operability of the Core Spray via maintenance (ie, header clamps or replacement). The staff will consider authorizinnfyc,lp&
operation based on a BECo submittal which wodld contain the following information
- "'c c >
su m us)
- 8108130022 910806 PDR ADOCK 05000293
....g.....
nac rosu m no,8m sacu mo OFFICIAL RECORD COPY
- ** "-32" 2
- l o
+
w
~
2 i
/
/
1.
A detailed ctiscussion of the inspection procedure to be used in the investigation of the cracking during the upcoming, outage, and a comparison of the new procedure to that used durf ig the last outage.
2.
A detailed description of the criteria which will determine the maintenance activities on the sparger (ie. clamping or replacement of the sparger),
specifically l
a.
The crack length and/or frequency which will require clamping b.
The crack length and/or frequency which will require replacanent c.
The accuracy of the measurements for anand b. (include assumptions) d.
The basis for a, b, and c above e.
A clear Boston Edison Co. commitment to clamp or replace if the criteria is met.
3.
A schedule for the following:
a.
completion of procedures to perform the inspection b.
completion of procedures to perform sparger maintenance or replacement.
c.
availability of tooling or any equipment necessary to perform maintenance.
4 d.
completion of training for personnel to perform any necessary maintenance operations.
8.
the installation / maintenance window for operations during the outage.
This should include estimated time for sparger replacement.
4 The pro.jected radiation doses to per&innel for the various maintenance contingencies, and a discussion of how the procedures minimize such doses.
5.
An analysis which demonstrates that the existing MAPHGR limits and assumptions regarding use of the Core Spray for ECCS compensate for any reduction in the margins of the original plant design (ie. 2 C.S.) for Cycle 6 operations.
Contingent on the acceptability of the submittal the NRC staff will approve Cycle 6 operation with the existing header, in advance of a review of'the information derived from the inspection during this outage. Such advance approval obviates any neg'd for the NRC to be in the critical path for restart of the facility due to this issue.
J"""^"'>
........... ~..
^4
..................l.........
NRC FORM 318 HO<eol NRCM O240 OFFICIAL RECORD COPY
- " "-32n24
w u
Boston Edison was requested to submit the information within approximately 30 days of the meeting.
Sincerely.,
Mark H. Williams, Project Manager Operating Reactors Branch f2, DL Enclosure DISTRIBUTION :
y Docket File x
065 ;,cg.
NRC PDR Local PDR T. Novak 01&E T. Ippolito M. Williams S. Norris J. Collins fleeting Attendees b
I omer>..... ORB #2..
..O..R...
euasar)......S...o..r. r.i. n.. Rp it g
........o
....ams.
- >... 3/.5/at.
. B/3./81.........hb./8 '........
Nac roau sie no.soinscu o24o OFFICIAL RECORD COPY
'uS* S * * -a29 2.
1 PILGRIM CORE SPRAY MEETING AGENDA 1.
INTRODUCTION -
JIM KEYES 0 PURPOSE OF MEETING 0 ATTENDEES-O 00TLIN5'0F PRESENTATION II, PILGRIM CORE SPRAY:SPARGER HISTORY J. KEYES III.
.SPARGER RE-EVALUATION EFFORTS -
DR. HuGa O'COMNi O IMAGE ENHANCEMENT 0 RESIDUAL STRESS EXPERIMENTS 0 FRACTURE MECHANICS STUDIES O RESULTS ADDITIONAL REASONS F'R CONTINUED OPERATION J. NICHOLSON IV.
O WITH EXISTING SPARGER 0 OYSTER CREEK DESTRUCTIVE TESTING O ALARA CONSIDERATIONS 0 RE-AFFIRMATION OF RELOAD LICENSING SUBMITTAL 0 PLANNED INSPECTIONS
~
.V CONCLUSIONS.
J. KEYes g.
\\
PILGRYMCORESPRAYSPARGERHISTORY_
. o 10 YEAR ISI
=
INDICATIONS ON-CSS FEB 1980 e
MEETINGS WITH BEC0/NRC FEBRUARY-29, 1980 MARCH 13, 1980 o
APRIL 3,1980 TECHNICAL SPECIFICATION CHANGE APRIL 29,'1980 SUPPLEMENT TO T.S. CHANGE o
~
o MAY 12,.1980 NRC SAFETY EVALUATION o
BECO ACTIONS TAKEN TO DATE e
6
-,--e m--~4 w
. -m Y,,
a-r,,,
3-~
c
- r
,,-.w-
.-',---n
, @* n e.
+ --
- SYNOPSIS OF SPARGER REEVALUATION EFFORTS 1.
REVIEW 0F LAST INSPECTION USING IMAGE ENHANCEMENT TECHNIQUES 2.
NEW CRACK GROWTH RATES PREDICTED-T0 BE CONFIRMED AT NEXT INSPECTION.
3.
RESIDUAL STRESS MEASUREMENT,S MADE ON TEST BENT PIPE CONFIRMS TREND. OF ANALYTICAL SOLUTION, INDICATES LOCAL AREAS OF TENSILE STRESS 4
4.
NEW INFORMATION & EXPANDED ANALYSIS CONFIRMS CONSERVATISM
]
OF ORIGINAL CRACK ARREST PREDICTIONS -
5.
USE NEXT INSPECTION TO VALIDATE CRACK GROWTH PREDICTIONS 1-i 6.
USE 0YSTER CREEK FINDINGS.TO REEVALUATE OUR ANALYSIS O
e
MerTlional Residual Stress. Based on simple, solid bent bes;
Elastic / Plastic, Elastic Relaxation Iiodel t
+d0 -
f S
e O
g
+20 O
O O
/
\\
O e '.+
o o
e.
G O
O p
0,{
i i
g.
I 0
O m
O 9
O' O
]
l l
b l
o o
o o
O 1
.-20 i
-40
-180
- -135
-90 0
+45
+90-
+135
+180 0
9 12 o' clock 3
6
)
Figure 5 Principal Residual Stresses (Nc.arertoMeridional) 9 Data Points I
o Points Based on.Synynetry j I ',
~
I
+ - Single Meridional Element.
1 3
.e e
PJLGRIM CORE SPPAY SPAP.GCR DESIBl EWLU 1
9
~~
f o
. PREDICTED txKLENGTH5 1*
1REA SEPT 1981 IMRCH 1985 1
AWAY FRoM WELD 3.2 IN 3.4 In 2
HELD PAZ.'
~
3.5 in 3
4.3 'In FRACTURE I'IECHANIcS ANALYSIS o
CRACK ARREST AwAY FRon WELD ~4 In o
ChA6k.'- ARREST AT HELD HAz ~ 10 In.
O
[, BA' SED U?CN 5 Ks1 SERVICE STRESS PLUS PE Assonn CRACK LENGi'-i oF 3 In. m JAN -[980
- 2. HELD DATA - AS HELDED (I' LEAN) 8PPn 0 2
- 3. FuRiiACE SENSITIZED. DATA GIVEs-10rn (Uppse 9
m
. m s"
UDDITYONAL REASONS FOR OPEliAD0ti RUH EXISTING SPARGERS o
EVALUATE CRACKIllG MECHANISMS FROM OYSTER CREEK DATA o
REPLACEMENT NOT-PRUDENT DUE TO ALARA AND DOWN TIME
' CONSIDERATIONS o
REAFFRIMATI-ON OF RELOAD IV LICENSE SUBMITTAL o
IMPROVED INSPECTION TEChin&UE TO BE USED AT NEXT REFUEL OUTAGE
- w S
s.
6 u - - -*'
CONCLULONS BECO'5 POSITION.ISTHATTilECSSISEULLYOPERATIONAL o
FRACTUREMECHdNIChSTUDIESINDICATECRACKARREST o
8 DEMONSTRATES THAT STRUCTURAL INTEGRITY WILL BE MAINTAINED o
- NOT A SAFETY CONCERN /CAUSE OF CRACKING NOT CONFIRMED /
THEREFORE, ALARA CONSIDERATIONS DO NOT JUSTIFY CHANGE 00T AT THIS TIME-o FUTURE PLAUS NEAR TERM o
IMPROVED ISI o
POSSIBLE REMOVAL OF MAPLHGR DERATE LONGER RANGE o
MAINTAIN COGNIZANCE OF OYSTER CREEK CSS EXAMINATION
~
~
.0 REASSES'S lie 8D' FOR SPARGlR REPl.$CEMEi!T o
REQUESi NRC C0tlCURRENCE WITH PLAN OF ACTION
~
o
,a.