ML18101B077

LER 95-023-00:on 950926,identified Eight SG Tubes Which Had Exceeded TS Plugging Criteria Due to Missed Eddy Current Indications.Structural Integrity Assessment Being Performed & Data Analyst Guidelines Being Developed

ML18101B077
Person / Time
Site:	Salem
Issue date:	10/24/1995
From:	Dulee R Public Service Enterprise Group
To:
Shared Package
ML18101B076	List: ML18101B075 ML18101B077
References
LER-95-023, LER-95-23, NUDOCS 9510300065
Download: ML18101B077 (4)

Text

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 14-951 EXPIRES 04/30/98 ESTIMATED BURDEN PER RESPONSE TO. COMPLY WITH THIS MANDATORY INFORMATION COLLECTION REQUEST: 50.0 HRS. REPORTED LESSONS LEARNED ARE INCORPORATED INTO THE LICENSING PROCESS AND FED LICENSEE EVENT REPORT (LER) BACK TO INDUSTRY. FORWARD COMMENTS REGARDING. BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH IT-6 F331, U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC (See reverse for required number of 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT 13150-01041. OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC digits/characters for each block! 20503.

FACILITY NAME 111 DOCKET NUMBER 121 PAGE 131 SALEM GENERATING STATION UNIT 1 05000272 1 of 4 TITLE 141 FAILURE TO PLUG STEAM GENERATOR TUBES DUE TO MISSED EDDY CURRENT INDICATIONS EVENT DATE 151 LER NUMBER 161 REPORT DATE 171 OTHER FACILITIES INVOLVED 181 FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL I REVISION MONTH DAY YEAR NUMBER NUMBER I

01 06 94 95 -- 023 -- 00 10 24 95 FACILITY NAME DOCKET NUMBER OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check one or more) 111 I MODE 191 4 20.2201(b) 20.2203(a)(2)(v) x 50. 73(a)(2)(i) 50. 73(a)(2)(viii)

POWER 20.2203(a)(1 I 20.2203(a)(3)(i) 50. 73(a)(2)(ii) 50. 73(a)(2)(x)

LEVEL (101 000 20.2203(a)(2)(i) 20.2203(a)(3)(ii) 50. 73(a)(2)(iiil 73.71 20.2203(a)(2)(ii) 20.2203(a)(41 50. 73(a)(2)1iv) OTHER 20.2203(a)(2lliii) 50.36(c)( 11 50. 73(a)(2)(v) Specify In Abstract below or In NRC Form 366A 20.22031all211ivl 50.36(c)(2) 50. 73(a)(2)(vii)

LICENSEE CONTACT FOR THIS LER (121 NAME TELEPHONE NUMBER (Include Area Codel Mr. Robert Dulee, Steam Generator Project Manager 609-339-5350 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

REPORTABLE REPORTABLE

~f~f~~f~~I~1I~~~f CAUSE SYSTEM COMPONENT MANUFACTURER CAUSE SYSTEM COMPONENT MANUFACTURER TO NPRDS TO NPRDS SUPPLEMENTAL REPORT EXPECTED 114)

I

~:~:~:~=~ :~:~:~=~ =~=~ =~:~:~::

EXPECTED MONTH DAY YEAR SUBMISSION IYES INO X (If yes, complete EXPECTED SUBMISSION DATE). DATE 1151 3 29 96 ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (161 During a review of prior outage test data to support estimations of Steam Generator (S/G) tube indication growth rates, eight tubes were identified to have exceeded the Salem Technical Specification plugging criteria of 40%

of tube wall as specified in the acceptance criteria of the surveillance requirements of Section 4 . 4 . 5 . 4 . Contrary to the Limiting Condition for Operations, Section 3.4.5, the unit was operated in modes 1 through 4 with steam generators that did not meet the operability requirements described in Section 4.4.5.4.

The safety significance and root cause are unknown at this time. An investigation is underway and should be completed to permit a supplementary report by March 29, 1996.

This is reportable per 10CFR50.73 (a) ( 2) ( i) (B) I a condition prohibited by the plant's Technical Specifications.

9510300065 951024 NRC FORM 366 14-951 PDR ADOCK 05000272 S PDR

NRC FORM 366A (4-96)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION FACILITY NAME 111 DOCKET NUMBER 121 LER NUMBER 161 PAGE 131 YEAR I SEQUENTIAL NUMBER I REVISION NUMBER SALEM GENERATING STATION UNIT 1 05000272 95 -- 023 -- 00 2 of 4 TEXT (If more epace is required, use additional copies of NRC Form 366AI 1171 PLANT .AND SYSTEM IDENTIFICATION Westinghouse - Pressurized Water Reactor Reactor Coolant System/Steam Generator {AB/SG}*

• Energy Industry Identification System (EIIS) codes and component function identifier codes appear in the text as {SS/CCC}.

IDENTIFICATION OF OCCURRENCE Missed Eddy Current Testing (ECT) indications during the 1993 Salem Unit #1 Refueling Outage (lRll) steam generator tube evaluations.

Event Date: January 6, 1994.

Discovery Date: September 26, 1995.

Report Date: October 25, 1995.

CONDITIONS PRIOR TO OCCURRENCE Defueled - Reactor Power 0%

DESCRIPTION OF OCCURRENCE To determine the growth rate of indications during the operating period between past outage lRll and current outage 1Rl2, a review of 1993 bobbin ECT data was performed. During this review, on September 26, 1995, bobbin probe indications with depths which exceed the Technical Specification plugging criteria of 40% of tube wall specified in section 4.4.5.4 were identified at Tube Support Plate (TSP) intersections for eight tubes (seven tubes with one indication each and the remaining tube with two indications) which were not plugged.

In 1993 the primary and secondary analysts did not correctly identify, as pluggable, three indications which are now evaluated as having depths of 68%, 85%, and 96% through wall. Two indications now evaluated as 42% and 79% depth were evaluated in 1993 by both the primary and secondary analysts as distorted indications which should be examined by Rotating Pancake Coil (RPC); the resolution analyst concluded that neither indication was pluggable or required follow-up inspection by RPC. For the four other indications, differences between the primary and secondary analyst were evaluated by the resolution analyst as not pluggable.

NRC FORM 366A (4-95)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (4-961 LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME 111 DOCKET NUMBER 121 LER NUMBER 161 .PAGE 131 YEAR I SEQUENTIAL NUMBER I REVISION NUMBER SALEM GENERATING STATION UNIT 1 05000272 3 of 4 95 -- 023 -- 00 TEXT (If more apace is required. use additional copies of NRC Form 366AJ 11 71 APPARENT CAUSE OF OCCURRENCE The cause of the missed bobbin coil probe indications is not known at this time.

PRIOR SIMILAR OCCURRENCES There is no prior similar occurrence at Salem of the identification of an ECT indication which should have been called at a previous inspection. A review of events previously reported to the NRC by other plants indicates that missed bobbin coil probe pluggable indications have been experienced at Sequoyah Unit 1, ANO Unit 2, North Anna Unit 1, Ginna, Yankee Rowe, and Maine Yankee.

SAFETY SIGNIFICANCE A structural integrity assessment is being performed by Westinghouse to demonstrate that the requirements of Reg. Guide 1.121 are met by the tubes with their as-found flaw configuration. Ultrasonic testing is being performed to verify the crack configuration, and in-situ pressure testing will be performed to support the structural integrity assessment. If the strcuctural integrity assessment demonstrates that the requirements of Reg.

Guide 1.121 have been met, this event will have no safety significance.

CORRECTIVE ACTIONS Salem Unit #1

1. A structural integrity assessment is being performed to confirm that affected tubes in their as-found condition meet the requirements of Reg.

Guide 1.121.

2. A number of corrective actions are being taken to assure that all tubes with ECT depth indications greater than 40% are plugged and to minimize any future missed call of a pluggable ECT indication. These corrective actions include:

a. An independent assessment of the training and qualification of analysts involved in the 1993 and 1995 analyses of Salem Unit 1 ECT data has been performed. This assessment indicates that there are no apparent procedural or regulatory violations. However, specific areas where the program for training and qualification of analysts could be improved were noted. Each of these areas has been discussed with the contractor.

NRC FORM 366A (4-95)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION 14-951

• LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME 111 DOCKET NUMBER 121 LER NUMBER 161 PAGE 131 YEAR I SEQUENTIAL NUMBER I RIMSION NUMBER SALEM GENERATING STATION UNIT 1 05000272 4 of 4 95 -- 023 -- 00 TEXT (If more space is required, use additional copies of NRC Form 366AI 11 71 CORRECTIVE ACTIONS (cont'd)

b. Data analyst guidelines specific to Salem Units 1 and 2 are being developed. P~ior to performing any S/G ECT inspections in either Unit #1 or Unit #2, all analysts will be trained and tested to demonstrate proficiency in the use of the guidelines.

c. A full length bobbin coil ECT inspection expansion of all unplugged tubes in all steam generators from the current 20% sample size will be performed to assure that all bobbin coil probe indications are analyzed during the current outage. The 1993 bobbin coil probe data will be reviewed for any additional pluggable indications identified in the current outage to assess the apparent growth rate of indications. This expanded inspection scope may identify additional bobbin coil probe indications which should have been analyzed as pluggable in 1993. This task will be completed by March 29, 1996.

d. All bobbin coil inspection data already taken will be reanalyzed. A PSE&G Level III examiner will provide oversight of this reanalysis effort. This task will be completed by March 29, 1996.

e. Steam generator tubes requiring plugging will be plugged based upon the results of tasks 2c and 2d prior to restart of Unit #1.

Salem Unit #2

3. The corrective action described in item 2b above for site specific training and testing will be implemented prior to performing ECT on Salem Unit #2.

4. Salem Unit #2's steam generators will have completed 100% tube inspections prior to Unit #2 restart. If a defective tube was missed in a prior outage, the planned inspection program should detect the defective tube and a supplement to this LER will be issued.

NRC FORM 366A (4-95)