ML20136D330

Forwards Response to NRC 851104 Request for Addl Info Re Radiological Aspects of upper-head Injection Removal & Radiological Impacts on Plant Operations.Final Decision Re Disposal Method Expected by Late Jan 1986

ML20136D330
Person / Time
Site:	Mcguire, McGuire
Issue date:	12/23/1985
From:	Tucker H DUKE POWER CO.
To:	Harold Denton, Youngblood B Office of Nuclear Reactor Regulation
References
TAC-57211, TAC-57212, NUDOCS 8601060125
Download: ML20136D330 (8)

Text

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e DUKE Powen Gonnwy P.O. HOX 33180 CIIAHLOTTE. N.O. 28242 HAL11. TUCKER TELEPHONE

- vmmrarsanmut (704) 373-4531 Nt%LSAB eBOD0(7F50N December 23, 1985

r. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention: B.J. Youngblood, Director PWR Project Directorate #4

Subject:

McGuire Nuclear Station Docket Nos. 50-369, -370

Dear Mr. Youngblood:

By letter dated November "., 1985, NRC Staff requested additional information reagrding the radiolog! cal aspects of UHI removal and related radiological impacts on~ plant operations.

Accordingly, please find attached Duke Power Company's response to this request. Should there be any additional questions in this area, Duke would be pleased to discuss them via conference call at a mutually agree-able time. Please advise us through the normal licensing channels.

Very truly yours, B~> Wi%

Hal B. Tucker RLG/jgm Attachment cc: Mr. Darl Hood, Project Manager Division of Licensing Office of Nuclear Regulatory Commission '

Washington, D.C. 20555 B601060125 851223 PDR ADUCK 05000369 W.T. Orders P PDR NRC Resident Inspector McGuire Nuclear Station

• Dr. J. Nelson Grace

/19[ AD - . morr (ar ontyi EB (BARARD)

U.S. Nuclear Regulatory Commission

/ "$5 @ ^d3 Region Il ass (staunct.nj

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101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 J

H.R. Denton December 23, 1985 Page 2 bec: N.A. Rutherford R.O. Sharpe J.B. Day J.G. Torre S.A. Gewehr P.B. Nardoci D.R. Bradshaw L. Lewis A.L. Snow W.D. Reckley T.L. McConnell E.O. McCraw MC-801.01

REQUEST FOR ADDITIONAL INFORMATION REGARDING RADIOLOGICAL ASPECTS OF UHI REMOVAL

1. Question:

Describe the actual hardware changes and activities that will be made to accomplish UHI removal. Include those construction steps which result ~

in radiological exposure to personnel or generate radioactive waste. Id-entify differences, if any, in these changes and activities for the two McGuire units.

Response

A surmary of the UHI modification including hardware changes and construction activities follow. Please note that there is no significant difference between the work at each unit. Also, note that the work steps are not necessarily in order. .

1. Work will begin with the erection of scaffolding and the set up of temporary lighting and service lines. *

2. Four safety injection system flow element orifice plates will either be rebored or replaced.

3. Reactor Vessel Head penetrations will be cut and prepped. A cap will then be welded on. The penetration and cap will be hydrotested.

4. The piping, valves, support / restraints and instrumentation associated with the Upper Head Injection system will be removed.

5. Various UHI piping interfaces with other systems will be capped.

6. Two 12" penetrations will be capped on the containment and auxiliary building sides.

7. Cold leg accummulator level transmitters will be relocated.

8. The accummulator lines will be capped at the accummulator.

9. A general clean-up of the affected areas including the removal of temporary scaffolding, etc. will be the last step in the modification.

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2. Question:

F Provide an estimate of the occupational radiation dose determined for the overall Upper Head Injection System removal project at McGuire 1 & 2.

l This should include the following:

a) Doses and manpower for major' subtasks b) typical dose rates expected c) maximum dose rates expected, and locations

' Response:

a) For purposes of following personnel exposure and manhour estimates, the UNIS deletion project was divided into 4 major subtasks.

, SUBTASK DOSE ESTIMATE (Person-Rem) MAN-HOUR ESTIMATE

1) Cut and cap auxiliary a) Duke 12.720 32

, head adaptors b) Vendor 5.000 10

2) Removal of piping, 30.790 1632 valves, and hangers

3) Cut and cap containment .550 200 penetrations l

4) Exposing head adaptors .22.715 680 (ie., Remove DRPI coil I

stacks, CRDM ventilation shield removal, insulation removal)-

! TOTAL 71.775 (Per-Unit) 2542 (Per-Unit) j NOTE: Man-hour estimates are actual in-area estimates supplied by craft supervisors.

b) Typical general area dose rates projected are as follows

1) 2-20 mr/hr along auxiliary building UHIS piping

{ 2) 20-30 mr/hr along lower containment UHIS piping

3)20-100 mr/hr along reactor head UHIS piping

c) Maximum projected dose rates range from 1000 to 1500 mr/hr at the auxiliary head adaptors.

?. Question:

Provide a comparison of dose incurred during task performance and dose avoided (e.g., reduced operations, maintenance, ISI for system components, seismic restrcints/ snubbers) over plant life by removal of the UHIS.

Response

The total projected dose avoided following deletion of the UHIS for McGuire Units 1 & 2 is 420.000 Person-Rem. The great majority of this dose is due to system maintenance operation, ISI, snubber inspections and Head Removal Prep. work. Thus, a net exposure savings of 276 Person-Rem, over the life of the plant, is anticipated.

4. Question: .

Identify measures to be taken to assure that doses to workers during task performance will be ALARA. This should cover, for example, task planning, special training, use of mockups, area and system decontamination and air-borne radioactivity, efforts to minimize number of workers and application of experience from similar efforts in the industry.

Response

The McGuire ALARA Staff is working directly with work supervisors in evalu-ating proposed methods for removal of the UHIS piping and associated hangers /

restraints (ie. , plasma-arc, remote cutting equipment, tri-tool). Temporary shielding will be considered and utilized when and where practical. The ALARA-staff will also identify to outage management unassociated work that could affect UHIS deletion exposure for integrated scheduling considerations (ie.,

sludgelancing). For instance, sludge lancing requires that the shell side of the steam generators be drained. As a result, dose rates around the steam generators increase. The above methods will ensure doses to workers are maintained ALARA.

5) Question: Identify the types and volumes of radioactive waste which are expected to be generated (e.g., piping components, insulation) and discuss disposal plans for these wastes.

Response: The types and volumes of radioactive waste expected are summarized below:

a) Low Radiation and Contamination Description Quantity 3 FT VALVES 21 EACH 61.5 0.75" DIA PIPE 150 FT 1.1 2" DIA PIPE 50 FT 2.0 8" DIA PIPE 50 FT 25.8 12" DIA PIPE 176 FT 198.7 12" DIA PIPE (radiused) 50 FT 56.4 14" DIA PIPE 16 FT 21.8 16" DIA PIPE 7 FT 12.4 18" DIA PIPE 28 FT 63.0 3

l0TAL 442.7 FT b) Medium Radiation and Contamination Description Quantity 3 FT VALVES 8 EACH 21.2 8" DIA PIPE 15 FT 7.7 0.75" DIA PIPE 43 'FT 0.3 8" GRAYLOC DISCONNECTS C Ufii 16.8 TOTAL 46.0 FT 3 c) High Radiation and C9ntamination Description 3 Quantitl FT 8" DIA PIPE 60 FT 31.0 5" DIA PIPE 26 FT 5.6 ADAPTERS 4 EACH 10.8 5" GRAYLOC DISCONNECTS 4 EACH 5.6 THERMAL SLEEVES 4 EACH 2.1 TOTAL 55.1 FT 3 d) NI Check Valves Description 3 Quantity FT VALVES 8 103.2

e) Hanger Materials 3

Description Quanitity FT Hangers 56 160.0 3

Total Volume To Be Processed - 807 FT

't Currently, Duke is considering four options for disposal of the UHI waste.

These are:

1) Burial at Barnwell as low-level waste

2) On-site decontamination by Duke, sell as scrap

3) On-site decontamination by vendor, sell as scrap

4) Off-site decontamination.by vendor Duke expects to reach a final decision on the best disposal method by late January, 1986.

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PTF/tdk 12-20-85

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6. Question:

-Identify and briefly discuss any special radiological problems which may be associated with this task (e.g., very high dose rates, very high contamina-tion levels, high radiciodine levels, need for multiple dosimetry),

Response

Following a walkdown of Reactor buidling UHIS piping in May 1985 and during pre-job planning meetings the ALARA staff has identified special radiological problems to be addressed and are as follows:

1) The majority of UHIS piping is routed through the overhead of lower 4

containment. Should debris generated during cutting of the piping be improperly contained, unassociated outage work below could be affected, resulting in delays and additional exposures.

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2) The McGuire ALARA staff projects very high contamination levels on UNIS piping between the auxiliary head adaptors and reipective accumulator injection line check valves.

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3) A thermal sleeve rests on the inside of the auxiliary head adaptors. When the adaptor is cut, the sleeve should fall through the refueling floor

and.inside the head stand. Thermal sleeve disposal following completion of the UNIS deletion may require remote handling and shielded packaging.

.Close contact is being maintained with work planners to effect solutions.