AECM-86-0186, Requests Response to Encl Rev to Justification for Relief Request I-00008 Re ASME Section XI Code Requirements for Inservice Insp of CRD & in-core Housing Welds & Flange Bolting,Per ,By 860801

Requests Response to Encl Rev to Justification for Relief Request I-00008 Re ASME Section XI Code Requirements for Inservice Insp of CRD & in-core Housing Welds & Flange Bolting,Per ,By 860801

ML20207F395
Person / Time
Site:	Grand Gulf
Issue date:	07/14/1986
From:	Kingsley O MISSISSIPPI POWER & LIGHT CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
AECM-86-0186, AECM-86-186, TAC-61929, TAC-62047, NUDOCS 8607220532
Download: ML20207F395 (6)

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MISSISSIPPI POWER & LIGHT COMPANY Helping Build Mississippi E dhilAMddE P. O. B O X 164 0. J A C K S O N. MIS SIS SIP PI 39215-1640 July 14, 1986 O. D. KINGSLE Y, J R.

YlCE PRE 510ENT NUCLE AR OPERAtlONS U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D. C. 20555 Attention: Mr. Harold R. Denton, Director

SUBJECT:

Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 License No. NPF-29 Revision to Inservice Inspection Relief Request No. I-00008 AECM-86/0186

REFERENCE:

MP&L letter to the NRC dated June 29, 1984 (AECM-84/0335)

The purpose of this letter is to request a revision to the justification for Relief Request No. 1-00008 submitted by letter referenced above. The subject Relief Request pertains to ASME Section XI code requirements for the Inservice Inspection of control rod drive and in-core housings welds and flange bolting at Grand Gulf Nuclear Station (GGNS) Unit 1.

Enclosed please find Attachment I which describes the revision to the subject relief request for your review. Attachment 2 is a markup incorporating the proposed revision into the relief request previously submitted by letter referenced above. The proposed revision was discussed with the NRC Staff on June 9, 1986.

The first re' fueling outage (RF01) for GGNS Unit 1 is scheduled to begin September 1, 1986. MP&L requests your response to the proposed revision to the subject relief request by August 1, 1986, in order to support the preplanning activities associated with the scheduled ISI inspections during l RF01.

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l If you have any questions, please advise.

Yours t ly,

$[ NON [ '

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l Attachments I cc: (See Next Page)

O J19AECM86061301 - 1 Member Middle South Utilities System a g

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AECM-86/d186 Page 2 cc: Mr.T.H.Cloninger(w/a)

Mr. R. B. McGeh'ee (w/a)

Mr. N. S. Reynolds (w/a)

Mr. H. L. Thomas (w/o)

Mr. R., C. Butcher (w/a)

Mr. James M. Taylor, Director (w/a) i Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Dr. J. Nelson Grace, Regional Administrator (w/a)

U. S. Nuclear Regulatory Commission Region II 101 Marietta St., N. W., Suite 2900 Atlanta, Georgia 30323 i

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Attachment 1 to AECM-86/0186 DISCUSSION OF PROPOSED REVISION TO INSERVICE INSPECTION RELIEF REQUEST NO. I-00008 Relief request No. I-00008 was submitted to the NRC by letter dated June 29, 1984. In Section VI (" Reasons why relief should be granted"),

paragraph 3, of the subject relief request, the following reason is given for requesting relief from ASME Section XI requirements: "The welds and bolting will be subject to hydrostatic testing per the requirements of ASME Section XI upon completion of each outage". This paragraph should be revised to read:

"3. The welds and bolting will be subject to a system leakage test (IWB-5221) each refueling outage and a hydrostatic test (IWB-5222) once each ten-year inservice inspection interval per the requirements of ASME Section XI".

ASME Section XI, IWA-5211 defines the differences between a hydrostatic test and a system leakage test. ASME section XI, Table IWB-2500-1 provides the schedule for each of these pressure tests. The hydrostatic test is performed at defined pressures above nonnal operating pressure and is performed only once in a ten-year interval as an inservice test. The system leakage test is conducted at the completion of each refueling outage after pressurization to normal operating pressure. MP&L intended to perform a system leak test at the end of each refueling outage and a hydrostatic test once each-ten year

-inservice inspection interval as specified in ASME Section XI.

The GGNS Unit 1 Reactor Pressure Vessel (RPV) has been designed for a limited number of hydrostatic test cycles. During the vessel construction and installation, a portion of the useable cycles were utilized in meeting ASME Section III's fabrication and testing requirements. Performance of a hydrostatic test of the RPV at each outage establishes a risk of consuming the allowed cycles before reaching expected plant life. In addition, a potential always exists for performing required hydrostatic tests of repaired or replaced components in the nonisolable portions of the RPV pressure boundary, thus utilizing additional test cycles.

The benefits gained by testing to pressures associated with a hydrostatic test in lieu of normal operating pressures does not justify the potential risk of exhausting the design life of the RPV prior to termination of plant life.

Therefore, MP&L requests.this clarification be incorporated into Relief Request No. I-00008.

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ATTACHMENT 2 GRAND GULF NUCLEAR STATION UNIT 1 REQUEST FOR RELIEF NO. I-00008 INSERVICE INSPECTION OF CONTROL ROD DRIVE AND IN-CORE HOUSINGS WELDS & FLANGE BOLTISG I. Component: Peripheral control rod drive housing welds (tube-to-tube, tube-to-flange) and bolting located on CRD housings.

II. Code: These portions of the CRD and in-core housing were designed and fabricated to the ASME Section III, Class I requirements. Applicable inservice inspections are to be -performed in accordance with ASME Section XI, 1977 Edition through and including Summer 1979 Addenda. l III.. Code requirements: 1. Welds located in 10% of the peripheral CRD housings require surface examination (dye penetrant) during each ten-year inservice inspection interval in accordance with ASME Section XI, Table IWB-2500-1, Examination Category B-0.

2. Pressure retaining bolting for the flange-to-flange joints, located on te CRD and incore housings, are required to be visually examined (VT-1) once every ten-year inspection interval in accordance with ASMI Section XI, Table IWB-2500-1, Examination Category B-G-2.

IV. Information to The weld areas and bolting are not accessible for support the inspection unless the control rod drive (CRD) support l

' determination that structure is removed. A 360 degree surface examination code requirements cannot be accurately accomplished from the outside, due are impractical: to interference from adjacent CBD housings. Inspection of the weld from the inside of the CRD housing would l

require that the control rod drive mechanism be removed, which could result in damage to the drive. With removal l

I of the drive, a small amount of teactor water would l

escape to the CRD cavity area, possibly causing

! contamination of personnel and equipment. The time frame associated with the CRD support structure removal and CRD mechanism would be approximately six (6) man hours per drive. Dosage received by personnel in this l

interval cannot justify the inspection process to possibly find a fault which could be discovered by

- excessive leakage in the drywell sump monitored per Operating License Manual (Technical Specification) j limits in effect.

V. Specific relief Permission is requested to exempt from inservice requested: inspection, the peripheral CRD housing welds (tube-to-tube, tube-to-flange), the eight (8) bolts associated

ATTACHMENT 2 GRAND GULF NUCLEAR STATION UNIT 1 REQUEST FOR RELIEF NO. I-00008 INSERVICE INSPECTION OF CONTROL ROD DRIVE AND IN-CORE HOUSINGS WELDS & FLANGE BOLTING V. Specific relief with each flange of 193 CRD housings and the four (4)

~ requested: bolts associated with each flange of 58 incore housings.

(Continued)

VI. Reasons why relief Request for exemption from inservice inspection should should be granted: be granted for,the following reasons:

1. The peripheral CRD housing welds have been examined by radiography and liquid penetrant methods and

- have been hydrostatic tested in accordance with ASME Section III code requirements.

2. All incore and CRD Housing bolting has been examined in accordance with the requirements of ASME Section III, which exceed the Section XI (VT-1) visual examination requirements.

3. The we ting vill be sub rostatic INSERT D testing per the r ASME Section XI upon each outage. ~

4. If the welds and/or bolts fail while in operation, the maximum leakage rate, by calculation, will occur at the peripheral CRD housing tube-to-flange weld. The maximum calculated leak rate is 681 spm. By criteria established in subarticle IWB-1200,

" exemptions by make up capacity", the normal makeup l

capability for GGNS is 878 gpm, which exceeds the calculated maximum leakage.

5. Leak detection is provided with the leakage detection system, with continuous monitoring in the control room.

6. The CRD housing supports would prevent ejection of i the housings in case of total failure of the welds or bolts.

7. Removal of the control rod drive support structure would result in hardships with no compensatory l increase in the level of quality and safety.

l VII. Alternate testing: None 1

NOTE: A similar request for relief from pre-service inspection requirements was accepted by NRC in GGNS Safety Evaluation Report, Supplement #2.

- oo ;o Attachment 2 to AECM-86/0186 4

INSERT-

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-3. The-welds and bolting will be subject to a' system leakage test (IWB-5221) each refueling outage and hydrostatic test (IWB-5222) once each ten-year inservice inspection interval per the requirements of ASME Section XI.

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