A97071, Provides Response to Request for Addl Info for Evaluation of Third 10-yr Interval Insp Program Plan Request for Relief CR-25,per NRC

Provides Response to Request for Addl Info for Evaluation of Third 10-yr Interval Insp Program Plan Request for Relief CR-25,per NRC

ML20199H457
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	11/21/1997
From:	Brons J COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ZRA97071, NUDOCS 9711260122
Download: ML20199H457 (10)

Text

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'ltIti(?N b 208i ZRA97071 November 21,1997 U.S. Nuclear Regulatory Commissior.

Washington, D.C. 20555 Attention: Document Cor. trol Desk

Subject:

Zion Nuclear Power Station, Units 1 ar.12 Response to Request for Additional information Regarding Relicf Request CR-25

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b'RC Docket Nos. 50-295 and 50-304

References:

1) Letter from C. Y. Shiraki, NRC. to I. Johnson, Comed, dated October 22,1997, Request for Additional Informatica for the Evaluation of the Third 10-Year Interval Inspection Program Plan Request for Relief No. CR Zion Nuclear Power Station, Units I and 2.

2) Letter from J. II. Mueller, Comed. to U.S. Nuclear Regulatory Commission, dated August 13,1997, Relief Request CR-25; IWA-5242(a) Requirements on Insulation Removal at Bolted Connections on Systems Containing Borie Acid.

This letter provides Comed's response to the Request for Ad'ditional Information (Reference 1) relative to proposed Relief Request CR-25 which was transmitted to the NRC via Reference 2.

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. ZRA 97071 Page 2 0f 2 Attachment A to this letter provides the requested additional information. Attachmeist B to this letter is a l ting of the commitments made by Comed in this submittal. Please direct any questin. you may have concerning this submittal to this office.

Respectfully,

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[t>Nohn Brons Site Vice President Zion Nuclear Station Attachments cc: - NRC Regional Administrator - Rill Zion Station Project Manager - NRR Senior Resident inspector - Zion Station OfDee of Nuclear Facility Safety - IDNS n IDNS Resident inspector i

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ATTACitMENT A (page 1 of 6)

RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION CONCERNING PROPOSED RELIEF REQUEST CR-25 Requested Information

1. For both units, specify the types ofinspections (magnetic particle, visual, liquid penetrant or ultrasonic) that were performed on studs or stud assemblics, the total number of studs or stud assemblics, the number that were inspected and the results of those inspections.

Comed Response There are 54 stud assemblies associated with each unit's reactor vessel head flange. Each assembly consists of a stud, a nut, and washers.

The examinations performed during the most recent Unit I shut dcwn are listed in Table 1. The examinations performed during the most recent Unit 2 refueling outage, Z2R14, are listed in Table 2.

Table 1 Most Recent Unit 1 Examinations Esamination Purpose of Exam Personnel Results Qualifications V F 1 of 54 stud Upon discovery that a VT-3 ASME Section XI No degradation as a result of assemblies. examination was missed prior to VT Level 11 boric acid buildup or leccage the head detensioning; all:tud was found. Furthermore, no assemblies were VT-1 examined VT-1 recordable indicetions after defensioning. The purpose of were found.

the exam was to verify that no degradation existed as a result of boric acid buildup from leakage.

VT 3 of 54 stud Upon discovery that a VT-3 ASME Section XI No boric acid deposits or assemblies. .xamination was missed prior to VT Level 11 degradation was found.

the head deter.sioning; all stud Furthermore, no VT-3 assemblies were VT-3 examined recordable indications were after detensioning. The purpose of found.

the exam was to inspect for -

evidence of boric acid deposits or degradation.

Ultrasonic Testing Upon discovery that a VT-3 ASME Section XI No recordable indicatier .

(UT)of 54 studs. examination was missed prior to LT Level 11 were found.

the head detensioning; all 54 studs were UT examined atler detensioning. The purpose of the exam was to verify no volumetric degradation exists.

A1TACllMENT A (page 2 of 6)

Table 2 Most Recent Unit 2 Examinations Examination Purpose of Exam Personnel Results Qualifwations c VT 1 of 9 nuts To ful011 ASME Section XI . ASME Section XI. No degradation as a result of and associated Third 10-Year Interval VT Level 11 boric acid buildup or leakage was washers. commitments (Relicf Request found. Furthermore, no VT-1 CR 19) to perform a VT 1, *ecordable indications were which looks for found.

discontinuities and imperfections on the surface of the component. This exam can verify no degradation as a result of boric acid buildup from leakage has occurred.

Magnetic Particle To fullill ASME Section XI ASME Section XI No recordable indications were Testing (MT)of 9 Third 10-Year Interval MT Level 11 found.

studs. commitments to perform MT on a sample of studs. MT exams detect discontinuities and imperfections on the surface of the component.

This exam can verify no degradation as a result of boric acid buildup from #

leakag; has occurred.

Ultrasonic Testing To fulfill ASME Section XI ASME Section XI No recordable indications were (UT) of 9 studs."' Third 10-Year Interval UT Level 11 foun(..

commitments to perform UT on a sample of studs. UT exams detect volumetric discontinuities and i' imperfections.

a) The examinations are associated with the same 9 stud assemblies.

a ATTACllMLNT A (page 3 of G Requested Information

2. Describe any inspections on horated systems that are required for reactivity control that are performed during plant shutdown or startups or during pressure increases or decreases and the most recent results of those inspection on both units.

Comed Response Zion Station has one procedure which requires visual examinatian of borated systems that are required for reactivity control and is performed during plant shutdown or startups or during pressure increases or decreases; TSS 15.6.21, " Visual Leak Examination of Class 1 Compenents (Reactor Coolant System Leak Test)." This procedure is typically performed during Mode 3 going into a refueling outage and during Mode 3 coming out of a refueling outage.

TSS 15.6.21 was most recently performed on Unit 1 on Merch,14,1996, during the Contednment Walkdown following the Z1M05 maintenance outage. While leakage was identified on some components (and subsequently dispositioned), the vessel head flange was not identified as having any leakage or boric acid residuc. TSS 15.6.21 was .nost recently performed on Unit 2 on

= September 19 & 20,1006, during the Z2R14 refueling outage, Initial Containment Walkdown.

Again, while leakage was identified on some components (and subsequently dispositioned), the vessel head flange was not identified as having any leakage or boric acid residue.

Requested Information

3. During the most recent plant shutdown, verify that the reactor vesel flange leakage detection systems were operable and that they did not indicate the presence of any leakage during the shutdowns.

Comed Response Zion Station's Reactor Coolant System (RCS) System Engineer reviewed the Operator and

, System Notebook logs and concluded that the reactor vessel flange leak detection systems were operable at the time of the most recent reactor shutdowns. No log entries were identified.

Furthermore, a review of the administrative out of services for 1906 and 1997 for both Units, (an administrative out of service would have been generated as a result of the alarm response) indicated that no adminstrative out of services for flange leak detection temperature alarms were generated. This would indicate that there was no evidence ofleakage from the vessel flange o-rings during the most recent operating cycles including plant shutdown.

ATTACllMENT A (page 4 of 6)

R(quested Information

4. Describe the qualifications and experience of the personnel who performed the most recent reactor head disassembles, and provide some assurance that any horie~ acid crystal buildup would have been documented ahd reported.

Comed Response For the most recent Unit I reactor head disassembly, Westinghouse was contracted to rmorm the scope of work. The Westinghouse personnel qualificatiew . perform Reactor Disass:mbly/

Reassembly and Fuel llandling Operations are based on formal, documented competency training administered 1 ; Westinghouse, and hands-on experience in the industry. In addition, the Westinghouse emplogo participated in Zion Station inprocessing training and Zion Station required reading training, which included ZAP 700-08," Problem identification Process."

For the most recent Unit 2 reactor head disassembly Zion Station's Mechanical Maintenance department was responsible. The Mechanical Maintenance crew consisted of a Supervisor, a Super "A" Mechanic (five years experience as an "A" Mechanic) and "A" Mechanics. The "A" Mechanics at Zion Station not only meet the requirement of ANSI N18.1 Nuclear Power Plant Personnel" Repairmen"; but also meet additional Zion Station specific requirements. These workers were also aware of the expectation that if an abnormal condition was identifed that a Problem Identification Form would be generated.

In Zion Station's submittal requesting Relief Request CR-25 and Licensee Event Report 97-013, transmitted via letter dated June 2,1997, from R. Starkey to U.S. Nuclear Regulatory Commission, Comed stated that there is reasonable assurance that detrimental or significant boric acid deposits would have been observed and reported. These statements were based on interviews with Comed's Senior Construction Contract Supervisor and the Mechanical Maintenance Supervisor who observed and were responsible for the most recent Unit I and Unit 2 reactor head disassembles, respectively. Both of these individuals stated that if detrimental /

significant boric acid had been present a Problem Idemification Form (PIF) would have been generated.

4 ATTACilMENT A (page 5 of 6)

Requested Information

5. Describe any inspections that are performed after the reactor head is detensioned.

State the purpose of the inspections, qualifications of the personnel performing the inspections, the results of the inspections, and provide some assurance that any horic acid crystal buildup would have been documented and reported.

Comed Response:

After the reactor hcad is detensioned, ASME Section XI Inservice inspections (ISI) are performed, as committed to in the ISI program. The most recent Unit I and Unit 2 ISI examinations assochted with reactor head disassembly are listed in Tables 1 and 2, respectively, ,

along with t.e purpose of the inspections, the qualifications of the personnel performing the inspections and the results of the inspections, in addition to the ISI examinations, procedure RC001-4, " Reactor Vessel licad Removal"is conducted. This procedure includes a step which requires an inspection of all reactor vessel head flange stud hole counterbores after cleaning. The acceptance criter. ion for this step in the procedure is that no boric acid buildup exists in the stud - .e countu wres. This procedure step is initialed by the Mechanical Maintenance personnel conducting the procedure, who are qualified as stated in the response to " Requested Additional Information 4." This procedure step t was completed and initialed for the most recent head disassembly on each unit.

Zion also performs Procedure TSGP-73," Reactor Vessel CRDM Canopy Seal Weld Exam."

TSGP-73 is required to be performed every refueling outage when the reactor vessel head is on the reactor vessel nead laydown stand. TSGP-73 was most recently performed on Unit 1 on September 22,1995, during the ZlR14 refueling outage. To satisfy the procedurt.1 requirements, a VT-3 visual examination was performed by a VT Level Ill qualified inspector. No evidence of leakage or boric acid residue was found. TSGP-73 was most recently performed on Uni: 2 on October 2,1996, during Ihe Z2R14 refueling outage. A VT-3 visual examination was performed by a VT Level 111 qualified inspector. Again, no evidence ofleakage or boric acid residue was found.

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• ATTACilMENT A (page 6 of 6)

Requested AdditionalIr, formation

6. Verify that the inspections of the reactor vessel flanges were the only Code required inspections that were omitted during the most recent disassembles of the reactor vessel heads. ,

ContEd Responac As stated in Zion Station Licensee Event Report 97-013, transmitted via letter dated June 2, 1997, from R. Starkey to U.S. Nuclear Regulatory Commission, the cause of the missed VT-3 inspection of the reactor vessel flange connection was a result of the ISI database not being updated aller receipt of the NRC Saf:ty Evaluation Report associated with Relief Request CR-

13. As committed to in the LER, the ISI database has been reviewed to ensure all proposed alternative :xaminations found in approved Relief Requests are in the database. This review was completed by Comed on August 25,1997. In addition, a detailed review of the ISI Program Plan and ISI schedule was completed by Comed on July 12,1997. Neither review identified any additional missed ASME Section XI Code required inspections.

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e ATTACilMENT B Page1of1 I,ist of Commitments identified in ZRA97071 The following table identifies those actions committed to by Comed in this document. Any other actions discussed is this submittal represent intended or planned actions by Comed. They are described to the NRC for the NRC's information and are not regulatary commitments. Please j notify Mr. Robert Godley, Zion Station Regulatory Assurance Manager, of any questions regarding this document or any associated regulatory commitments.

Commitment Committed Date or Outage i

None N/A L

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