A97013, Transmits Request for Authorization to Use Alternative Requirements of Article IWA-5242(a) for Insp of Rv Flanges During Current Unit 1 & 2 Outages Z1R15 & Z2R14

Transmits Request for Authorization to Use Alternative Requirements of Article IWA-5242(a) for Insp of Rv Flanges During Current Unit 1 & 2 Outages Z1R15 & Z2R14

ML20210L366
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	08/13/1997
From:	Mueller J COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ZRA97013, NUDOCS 9708210106
Download: ML20210L366 (8)

Text

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hon brnt rating Mauon 101 Muloh lloules.ird Won,11 (itu m 279' n i w .<,2m i ZRA97013 August 13,1997 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attn: Document Control Desk

Subject:

Zion Nuclear Power Station, Units 1 and 2 Relief Request CR-25; IWA 5242(a) Requirements on Insulation Removal at Bolted Connections on Systems Containing Boric Acid NRC Docket Nos. 50 295 and 50-304

References:

1) Letter from T. W. Simpkin, Commonwealth Edison, to U. S, Nuclear Regulatory Commission, dated June 20,1995

2) Letter from R. A. Capra, USNRC, to D. L. Farrar, Commonwealth Edison, dated September 1,1995 This letter transmits a request for authorization to use an alternative (CR 25) to the requirements of Article IWA 5242(a) for the inspection of the reactor vessel flanges during the current Unit I and 2 outages, ZlRIS and Z2R14. Authorization of the proposed alternative is being requested because the provisions of an existing relief request (CR-13) were not followed during the current outages, and it is no longer possible to comply with these provisions. Additionally, compliance with IWA 5242(a) would either require an unnecessary thermal cycle on the reactor pressure vessels, or require personnel to work on high temperature equipment. It would also result in additional personnel radiation exposure.

The proposed alternative consists of performance cf a VT-2 inspection for leakage at the reactor vessel flange with the insulation installed. This inspection would be conducted following a four hour hold period with the reactor coolant system at normal operating pressure. Commonwealth Edison (Comed) considers that the proposed alternative will provide an acceptable level of safety and quality for the next operating cycle ofeach unit.

For subsequent outages, Comed will either comply with the conditions of the existing relief request CR-13, comply with the requirements ofIWA 5242(a), or obtain cpproval of a revision to the existing relief request CR 13.

The request for a proposed alternative is provided as Attachment I to this letter, g' l J

9708210106 IP" ^ = =970813g;P I!IE BllJlllIllJig m.m.m o,e,

l ZRA97013, Page 2 of 2 Comed requests approval of this relief request prior to October 1,1997, which is the currently planned date for the Unit 2 restart.

Please direct any questions you may have concerning this submittal to this omce.

Respectfully.

- ij , 'I -

J.11. hiueller Site Vice President Zion Station Attachments cc: NRC Regional Administrator-Rlll Zion Station Project hianager - NRR Senior Resident inspector - Zion Station Omce of Nuclear Facility Safety - IDNS IDNS Resident inspector Zior. NLA hiaster Files Reg Assurance File DCD Licensing

4 ZRA97013 Attachment 1

Zion Station 3rd Intenal Inservice inspection Plan l'

lst Period I

, '. RELIEF REQUEST CR 25 Page 1 of 3 COMPONENT II)ENTIFICATION:

Code Class: 1

Reference:

Table IWB 25001, IWA-5242(a)

Examination Category: BP ltem Number: B15.10

Description:

Relief from requirement to remove Insulation from reactor vessel flange for performance of VT 2 visual examination at normal operating pressure, during the 3rd ISI interval,1st Period, ZlRIS, and Z2R14 Units: Zion Units 1 and 2 CODFJ1EOUiREMENB:

10 CFR 50.55a(g)(4) requires that ASME Code Class I components meet the inservice inspection requirements of Section XI of the ASME Boiler and Pressure Vessel Code.

Table IWB-2500-1 requires a reactor coolant system (RCS) leakage test each refueling outage, with a VT-2 visual inspection in accordance with IWA 5240.

Article IWA-5242(a) of Section XI of the ASME Boiler and Pressure Vessel Code states:

"For systems borated for the purpose of controlling reactivity, insulation shall be removed from pressure retaining bolted connections for visual examination VT 2."

DACKGROUND:

Comed previously proposed an alternative to the requirements of IWA-5242(a)in Relief Request CR-13, which was submitted to the NRC via a letter from T. W. Simpkin dated June 20,1995. That attemative included a VT-3 inspection of the reactor head bolting with the insulation removed and the RCS depresurized pier to dismantling the reactor vessel head joint each outage. Relief Request CR-13 was approved in an SER transmitted via a letter from R. A. Capra, U. S. Nuclear Regulatory Commission, to D. L Farrar, Comed, dated September 1,1995.

In April of 1997 it was determined that the above described VT-3 inspection had not been perfomied for the two Unit 1 outages (ZlR14, ZlRIS), and the one Unit 2 refueling outage (Z2R14) that have begun since Relief Rcquest CR-13 was approved. The cause and corrective actions for the failure to perform the VT-3 are documented in Licensee Event Report 50-295-97-013-00, transmitted to the NRC via a letter from R. Starkey, dated June 2,1997.

Zion Station 3rd Interval Inservice inspection Plan 1st Period i

'. '. RELIEF REQUEST CR 25 Page 2 of 3 MACKGROUND (cond:

Unit 1 and 2 are currently in outages ZlR15 and Z2R14. For both units, the initial dismantling of the reactor vessel head joint has alceady been completed (potentially removing evidence ofleakage that may have remained from the previous operating cycle, such as accumulated boric acid crystals). Therefore, it is no longer possible to perform the alternative VT-3 inspection prior to dismantling the reactor vessel head joint, as described in Relief Request CR 13, ,

Prior to restart of Units I and 2 from their current outages, it will be necessary to either comply with the requirements of IWA 5242(a), or obtain approval of a different altemative than that specined in the currently approved Relief Request CR 13. Compliance with IWA-5242(a) would require either an additional thermal cycle of the reactor vessel to conduct a cooldown for reinstallation of the insulation aner inspection, or require subjecting the personnel installing the insulation to the dangers of working on high temperature components.

Also, for Unit 2, additional radiation exposure would be required to remove and reinstall the insulation, since it had already been re installed when the failure to perform the VT 3 was identined.

Accordingly, Comed is proposing a different alternative (Relief Request CR 25) than that speciGed in the currently approved Relief Request CR-13. The basis for CR-25 is provided in the following section.

HASIS FOR RElJEF:

'10 CFR 50.55a(a)(3) states: " Proposed alternatives to the requirements of paragraphs (c), (d),

(c), (0, (8), and (h) of this section or portions thereof may be used when authorized by the Director of the Omce of Nuclear Reactor Regulation. The applicant shall demonstrate that:

(i) The proposed attematives would provide an acceptable level of quality and safety..."

Comed considers that the proposed alternative would provide an acceptable level of quality and safety. Unlike other bolted connections that are subject to the requirements of IWA-5242(a), the reactor head joint is dismantled every refueling outage. The most recent dismanttings were observed by individuals knowledgeable of the signi0cance of evidence of boric acid leakage in the vicinity of the joint. While these individuals were not speci0cally quali0ed for VT inspection, there is reasonable assurance that any signincant boric acid deposits would have been observed and reported.

= .. .

Zion Station 3rd interval Inservice Inspection Picn Ist Period

'. '. RELIEF REQUEST CR 25 Page 3 of 3 jiASIS FOR REl.lEF (cont.h Additionally, VT 1, VT 3, and ultrasonic examinations were conducted on all Unit I reactor head studs aller dismantling during the current outage, and no degradation of any type was observed. Since boric acid would attack the carbon steel studs, this indicates that there was no significant leakage over the previous operating cycle. During the current Unit 2 outage, selected stud assemblies were examined in accordance with the Inservice inspection Program, which included magnetic particle examinations and ultrasonic examinations. Again, no degradation of any type was observed.

Finally, if leakage were to occur at the reactor head joint during the operating cycle, it would likely be indicated by the leak detection system. The reactor vessel flange and head are scaled by two hollow metalN 0 rings. Seal leakage is detected by means of two leak-off connections; one between the inner and outer ring, and one outside the outer 0 ring. A temperature sensor in the leakoff line would indicate the leakage by a high temperature alarm.

As required by IWA-5243, the leak detection system will be verified operative during the RCS leakage test.

Comed considers that the absence ofleakage evidence from the most recent dismantlings of both reactor head joints, the ability to detect leakage while operating, and the proposed alternative described below, will provide an acceptable level of safety and quality for the next operating cycle of each unit, l'ItOPOSED ALTERNATIVE:

6 Comed proposes the following alternative to the requirements of Article IWA 5242(a) for the inspection of the reactor vessel flanges for Unit I and 2 outages Z1RIS, and Z2R14:

A VT-2 inspection for leakage at the reactor vessel llange will be performed with the insulation installed. This inspection will be condt.cted following a four hour hold period with the RCS at normal operating pressure. For subsequent outages, Comed will either comply with the conditions of the existing Relief Request CR-13, comply with the requirements of IWA-5242(a), or obtain approval of a revision to Relief Request CR-13.

o

i ZRA97013 F

Attachment 2

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0

ZRA9701)

Pcge1ofl I.ist of Contmitmenin Idemiluni in this Hellef iteggtg ihe following table identines those actions committed to by Comed in this document.

Any other netions discussed is this submittal represent intended or planned actions by Comed. They are described to the NitC for the NRC's infonnation and are not regulatory

e. umitments. l> lease notify hir. Robert Godley, Zion Station Regulatory Assurance hinnager, of any questions regarding this document or any associated regulatory commitments.

Commitment Committed Date or Outage None NA i

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