ML20236D131

Safety Evaluation Re Util Request for Relief from Schedular Requirements for Performance of Visual Insp & Hydrostatic Test of CRD Withdrawal & Insert Lines.Granting of Request Recommended

ML20236D131
Person / Time
Site:	Brunswick
Issue date:	10/22/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20236D089	List: ML20236D088 ML20236D131
References
NUDOCS 8710280032
Download: ML20236D131 (4)

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_,. UNITED STATES E o NUCLEAR REGULATORY COMMISSION p WASHINGTON, D. C 20666 x.....,/

I SAFETY EVALUATION BY THE 0FFICE OF NUCLEAR REACTOR REGULATION RELATED TO RELIEF FROM SCHEDULAR REQUIREMENTS '

'FOR' PERFORMANCE OF VISUAL INSPECTION-AND HYDROSTATIC TEST 0F CONTROL ROD DRIVE WITHDRAWAL AND INSERT LINES i

~ CAROLINA POWER AND LIGHT COMPANY BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 & 2 I DOCKET NOS.-50-325 AND 50-324 I. BACKGROUND INFORMATION .

.The Technical Specifications for the Brunswick Steam Electric Plant, Units l'8 2 state that inservice inspection of ASME Code Class 1, 2, .

and 3 components shall be performed in'accordance with the requirements I of the applicable edition and addenda of Section XI except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i). The Section XI Code edition and addenda applicable to the Brunswick Steam Electric Plant, Units 1 & 2 are the-1977 Edition with Addenda through the Summer 1978.

Pursuant to 10 CFR 50.55a(g)(5), if a licensee determines that conformance with a requirement of Section XI is impractical for its facility, informa-tion in support of the determination is submitted to the Commission and relief from the requirement is requested. The Commission will evaluate t the determination that the requirement'is impractical and may grant such relief and may impose alternative requirements as'it determines are authorized by law and will not endanger life or property and is otherwise in'the public interest giving due consideration to the burden upon the licensee that could result if the requirements were imposed. l By letter dated September 28, 1987, Carolina Power & Light Company, the licensee, submitted to the NRC a request for relief from performing the 1 hydrostatic test requirements of Section XI at or near the end of the i ten-year inspection intervals at Brunswick Steam Electric Plant, Units ,

1 & 2. Information in support of the request was provided. This  ;

information and the staff's bases for granting the relief are given in- l this report. 3 II.Section XI Code Requirements (1977 Edition through Sunrner 1978 Addenda)

The pressure retaining component within each system boundary shall be  ;

l subjected to a system hydrostatic pressure test each inspection  ;

interval. The system hydrostatic test shall be conducted at a test I pressure of at least 1.10 times the system pressure Psv for systems with  ;

Design Temperature of 200 F or less, and at least 1.25 times the system j pressure Psv for systems with Design Temperature above 200 F. The system

pressure Psv shall be the lowest pressure setting among the number of safety or relief valves provided for overpressure protection within the boundary of the system to be tested.

[ 8710280032 871022 PDR. ADOCK 05000324 G PDR

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The visual-examination, VT-2 sh'all be conduct'ed by examining the

- accessible external exposed surfaces of pressure retaining _ components for evidence of leakage. The Owner shall prepare records of the examinations and tests.-

I 1III. Relief Requested by Licensee Relief is requested from Section XI of the ASME Code, 1977 Edition through the Summer 1978 Addenda, Category C-H, which requires a hydrostatic pressure test be conducted at or near the end of the inspection interval'. This request is applicable to the Class 2 CRD .

insert / withdrawal lines.  !

As the VT-2 examination on these lines cannot be fully documented, CP&L l proposes to reperform the hydrostatic pressure test on these lines during 1 the next refueling outage of each unit. These outages are currently scheduled to commence in January 1988 for Unit 2 and November 1988 for Unit 1.. The unmodified inspection interval as defined in ASME Section XI,

- paragraph IWA-2420, has; expired for both units.

IV. Licensee's Justification for Requesting Relief i During the first inspection interval, Periodic Test PT-80.1, Reactor Pressure Vessel Hydrostatic Test, was performed several times for Units i 1 and 2 with the most recent one during the 1985 Unit I refueling outage  :

and the 1986 Unit 2 refueling outage, respectively. Each one pressurized  !

the Class 1 reactor coolant boundary. The 137 Class 2 CRD insert and )

withdrawal lines which extended from tha CRD housings to the HCUs cannot  ;

be isolated from the reactor coolant .,oundary and were, therefore, pressurized to the reactor coolant hydrostatic test pressure. A review of the physical location of these lines relative to other piping  ;

specifically identified in the test procedure provides reasonable assurance that a VT-2 examination was performed. This is further supported by the definition of a VT-2 examination which is a general inspection, rather than a specific component inspection (e.g., insulation joints and low points are inspected, not specific welds).

The CRD piping inside containment was pressurized for a minimum of four hours which exceeds the ten-minute hold time for this uninsulated siping. .The piping outboard of valves V101 and V102 was previously lydrostatically tested and subjected to a VT-2 inspection with no pressure boundary leakage detected. Any safety concerns are mitigated by

' the fact that a single-line failure for a CRD insert or withdrawal line would immediately insert the control rod using reactor vessel pressure.

Per NUREG-0803, Generic Safety Evaluation Report Regarding Integrity of BWR Scram System Piping, the CRD insert and withdrawal lines are small in diameter, conservatively designed and of high quality. In the event of a break in a CRD ~line under operating conditions:

1. The leak is within the reactor coolant makeup capability, and the CRD contains a restricted flow area that limits the reactor coolant loss to a small quantity, f.

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.The reactor can be shut down'and cooled d'own in.an orderly and.

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controlled manner.. j

3. . No? leakage from the scram discharge header, where flow from all Other CRD withdrawal lines is accumulated following a scram, will occur through the break because of the existence of a check valve

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between the.SDV and the withdrawal line manual isolation valves.

The failure of a single CRD unit (control rod drop accident) has been

.previously ' analyzed in chapter 15 of the FSAR.

V.- Staff Evaluation and Conclusions The licensee requests' to delay the hydrostatic tests and VT-2 examinations of the CRD lines at Brunswick Units-1 &~2 until the next scheduled' refueling outages, November 1988 for Unit I and January 1988

..for Unit 2.Section XI. required the hydrostatic test and VT-2 examina-tion to be completed by November 1986 at Unit 2 and requires completion of the test and examination by' March 1988 at Unit 1, giving credit for a one-year extension of the ten-year interval allowed by the Code. Since the Units are operating with refueling outages scheduled as stated above,

it is impractical to comply with the Code schedular requirements at this time.

Information provided by the licensee infers that the lines were

'.hydrostatically tested and visually examined near the end of the' ten-year ,

intervals in accordance with Code requirements. However, documentation verifying that the tests and VT-2 examinations were performed does not exist. Since the vessels and associated piping were subjected to the hydrostatic pressure test and the CRD lines cannot be isolated from the vessels pressure retaining boundaries,'a conclusion can be drawn that the lines were subjected to the hydrostatic pressure also. Leakage from the lines most likely would have been detected during visual examination of the vessels and piping in the immediate areas of the CRD lines, had any failure occurred.

The consequences of a break of a CRD withdrawal or insert line have been analyzed. A break of either line would result in a control rod insertion and the loss of coolant from the pressure boundary is well within the makeup capability of the units. If a break should occur, the plants can i

be shut down in an orderly manner.

Based on the above, the staff finds that imposition of the Code require-ments prior to the scheduled refueling outages at Brunswick Units 1 & 2 would place an unwarranted burden on the licensee without due compensation of increased plant safety. The CRD lines have been subjected in recent years to hydrostatic test pressures without evidence of loss of their structural integrity. Allowing the plants to operate until the next scheduled refueling) outages (November 1988 and January 1988 for Units 1 l

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po'ses.an insignificant.(if any) risk in their safe operation due to the lack of documentation of. visual examination of the CRD lines'. The staff -l t

L therefore, concludes that relief from the schedular requirement for performing and documenting the hydrostatic tests of the-CRD lines at  :

- . ' Brunswick-Units 1:& 2 may be. granted as requested.  !

.Date:  ;,

I Principal Contributor: G. Johnson  ;

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