ML20050D633
| ML20050D633 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 04/02/1982 |
| From: | Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 16149, NUDOCS 8204120379 | |
| Download: ML20050D633 (7) | |
Text
_.
O Colisumers Power
,,,,,, m Q&
Vice President - Projects, Engineenng and Construction 80-09 #5 General Offices: 1945 West Pernall Road, Jackson, MI 49201 * (517) 788 0453 April 2, 1982
.o 1 \\& t Mr J G Keppler, Regional Administrator
/\\\\
R)
US Iluclear Regulatory Commission d
,j Region III Q
jf CJ f
t 799 Roosevelt Road gf n h ) g' g$
9 M
Glen Ellyn, IL 60137 S:$
'10 MIDLAND PROJECT - UIIITS 1 AND 2 C) e DOCKET NOS 50-329 AND 50-330
/f LOW ALLOY QUEilCliED AND TEMPERED BOLTING 1 INCHES g
AND GREATER IN SUPPORT OF SAFETY RELATED SYSTEMS 4
FILE:
0.h.9.h6 SERIAL: 161h9
Reference:
J W Cook letters to J G Keppler, Same Subject :
(1) Serial 10996, dated Jrmuary 9,1981 (2) Serial 11526, dated March 31, 1981 (3) Serial 13690, dated September 29, 1981 (b) Serial lh666, dated January 15, 1982 This letter, as were the referenced letters, is an interim 50.55(e) report concerning the status of the subject bolting.
provides a description of the corrective actions in progress to resolve the problem.
Another report, either interim or final, will be sent on or before July 9,1982.
WRB/lr l : MCAR LSA and B, Interin Report 5, dated March 22, 1982 CC: RJCcok, URC Resident Inspector Midland Nuclear Plant Document Control Desk, NRC Washington, DC
?
s2on20379 e204o2 APR 0
PDR ADOCK c5000329 Q
S PDR l
. = _. - _ - _. ~.
I J
i 2
i Serial 16149 j
80-09 #5
~
i CC:
CBechhoefer, ASLB Panel RSDecker, ASLB Panel j
FPCowan, leLB Panel
)
JHarbour, ASLB Panel l
AS&L Appeal Panel i
MMCherry, Esq MSinclair BStamiris CRStephens, USNRC WDPaton, Esq, USNRC FJKelley, Esq, Attorney General SHFreeman, Esq, Asst Attorney General
[
WiiMarshall GJMerritt, Esq, TNK&J t
l 1
i i
4 i
}
4 I
1.
l 4
i I
i j
i l
1 1
I w
I 1
l i
I 1
l I
i i
Serial 16149 80-09 #5 Bechtel Associates ProfessionalCorporation 63330 636ei 1
SUBJECT:
MCAR 45A and 45B (issued 12/18/80)
INTERIM REPORT 5 DATE:
March 22,1982 PROJECT:
Consumers Power Company Midland Plant Units 1 and 2 Bechtel Job 7220 Introduction The discrepancies discussed in this report concern the hardness values of the anchor and connecting studs for the reactor coolant pump (RCP) snubbers.
Background
MCAR 45A The RCP snubber anchor studs are 2-1/4, 2-1/2, 3, and 3-1/2 inches in diameter and vary in length from 3'-6" to 7'-1".
They are embedded in the secondary shield wall and the refueling canal wall. Also included are 2-inch and 2-1/4-inch diameter connecting studs approximately l'-10" long that connect the snubbers to a structural steel transition piece.
The anchor studs are partially embedded in the concrete and the con-necting studs are in place. The snubbers restrain the RCPs during seismic and/or loss-of-coolant accident (LOCA) events.
The studs were purchased from various vendors during 1977 and 1978 by Bechtel construction in accordance with either ASTM A 354, Grade BD, or ASTM A 540, Grade B23, Class 3.
They were intended to be tensioned to a preload up to 96 kai to maintain the specified snubber spring rates under all loading conditions. Prior to tensioning, to ascertain that the studs could withstand long-term loads of this magnitude without becom-ing susceptible to stress corrosion cracking, Consumers Power Company re-quested Teledyne Engineering Services (TES) to conduct hardness tests on the exposed end of the embedded and connecting studs. TES conducted these hardness tests from November 21 through November 23, 1980. The test results showed that 207 studs of 384 tested are outside the range of hardness speci-fled by the ASTM specifications.
MCAR 45B On November 26, 1980, Consumers Power Company expanded the 10 CFR 50.55(e) report to include, as potentially reportable, all low-alloy quenched and tempered bolting materials 1-1/2 inches in diameter and larger used in support of safety-related systems.
f Bechtel Associates Professional Corporation
'6"o*d'o" 063607 d
MCAR 45A and 45B Interim Report 5 March 22, 1982 Page 2 Investigative Action MCAR 45A Aptech Engineering Services of Palo Alto, California, was retained by Consumers Power Company to review the hardness data taken by TES, and to evaluate the effect of the measured hardnesses on the ability of the studs to withstand preload, operating, and accident loadings. Based on preliminary Aptech evaluations, it has been decided to lower the stud preload (to a maximum of 12 ksi) to preclude failure because of stress corrosion cracking. Aptech has confirmed that a maximum preload of 12 ksi is low enough to preclude stress corrosion cracking for the hardness ranges under consideration.
Instructions have been issued to construction to preload the studs to 9 ksi, a value lower than the maximum pe rmissible. A tolerance of +3 ksi is allowed.
This preload value, when reduced by temperature and relaxation losses, exceeds 3 ksi, a value in excess of the minimum preload of 1.5 ksi re-quired by Babcock & Wilcox during operation. New spring rates have been submitted by Bechtel to B&W.
B&W is proceeding with the new seismic and LOCA analysis of the reactor coolant system.
ITT Grinnell, supplier of the snubbers, has also been informed of the change in the preload.
Grinnell stated that there is no effect on the snubbers or on the spring rate of the snubbers themselves.
Aptech has submitted a draft report on the assessment of the reactor coolant pump snubber anchor bolts.
Based on this report, the preload of 12 ksi maximum is acceptable and the preliminary allowable stress limits for operation and short duration loading are greater than the calculated bolt stresses based upon the capacity of the snubbers.
Procurement documentation packages for these studs have been reviewed to determine whether any additional action is required. A report on this review is being expedited and will be included in the next interim report.
MCAR 45B Consumers Power Company is leading the investigation required by this MCAR. Commonwealth Associates, Incorporated (CAI) of Jackson, Michigan, has been retained by Consumers Power Company to review safety-related
+63330 Bechtel Associates Professional Corporation MCAR 45A and 45B 063007 Interim Report 5 March 22, 1982 Page 3 purchase orders and identify those purchase orders including low-alloy quenched and tempered steel (LAQTS) bolting and/or component material.
The initial ef fort has been completed; however, additional purchase orders and LAQTS materials have been identified. CA1 is currently onsite gather-ing data that will be used in evaluating the LAQTS materials. This acti-vity is currently scheduled to be completed by June 11, 1982.
Most of the review being conducted on the LAQTS bolting and component support materials consists of field hardness testing. This testing is being performed by Consumers Power Company and cal. This activity began in December 1981 and is estimated to be completed by September 1982.
Science Applications Incorporated (sal) of Palo Alto, California, has been retained and has developed a sampling plan to determine the quantity of items to be tested. SAI is also providing statistical services in preparing the hardness data for evaluation.
l Aptech Engineering Services of Palo Alto, California, has been retained l
to assist in evaluating the LAQTS materials purchased by identifying which materials are LAQTS and require testing. Aptech is also assisting in the analysis of the hardness test results.
Corrective Action MCAR 45A Construction has been instructed to preload the snubber studs to 9 +3 ksi.
A procedure was developed by B&W construction to ensure that the studs are tensioned as required. This work has been completed for Unit 2, and is presently in progress for Unit 1.
Engineering has made a preliminary comparison of the calculated anchor bolt stresses with the Aptech allow-able stresses. These stresses, based on the capacity of the snubber, are within the preliminary Aptech allowable limits. A final check of stresses will be made upon receipt of B&W Specification 1235, Reactor Coolant System Foundation and Nozzle Loadings, scheduled for issue December 1982. At that time, the need for further corrective action will be determined.
MCAR 45B Quality control receipt inspection will include hardness testing of LAQTS bolting component support materials and is being established to preclude utilization of defective materials.
_~
Bechtel Associates Professional Corporation 6 3 3 '11 CAR 45A and 45B Q638Q[
Interim Report 5 March 22, 1982 Page 4 Safety Implications MCAR 45A If the subject studs were tensioned according to the original design re-quirements, there may have been a safety deficiency in that some of the studs could have failed due to stress corrosion cracking.
If uncorrected, this deficiency could adversely affect the safety of Midland plant opera-tions during the expected life of the plant.
MCAR 45B Presently, the existence of adverse safety implications relative to other safety-related bolting is undetermined.
Reportability This condition relative to the reactor coolant pump snubber studs was identified as "potentially reportable" by Consumers Power Company to the NRC under 10 CFR 50.55(e) on November 25, 1980.
MCAR 45A Submitted by: jd*p
[S.L.
Sobkowski Civil Group Supervisor O
Approved by:
=
M L.H. Curtis M Project Engineering Manager
% ~ d !,
Concurrence by:
s E.H. Smith Engineering Manager s
Concurrence by.
M.A. Dietrich
['
Project Quality Assurance Engineer
h3*:,3C Bechtel Associates ProfessionalCorporation 063807
!! CAR 45A and 45B Interim Report 5 March 22, 1982 Page 5 MCAR 45B M
Submitted by:
L.A. Dreisbach Mb n
Approved by:
n gg 4 L.ll. Curti Q Project Engi,neering Manager Concurrence by:
% o.[
\\
E. ll. Smith Engineering Manager Concurren e by:
C, gM.A.Dietrich Project Quality Assurance Engineer
(
t 1
i