ML20062E087
| ML20062E087 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 07/29/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20062E086 | List: |
| References | |
| NUDOCS 8208060332 | |
| Download: ML20062E087 (13) | |
Text
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UNITED STATES
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g NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 3 , t
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORT FOR RELIEF FROM CERTAIN INSERVICE INSPECTION REQUIREMENTS TOLEDO-EDISON COMPANY AND CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION, UNIT 1 DOCKET NO. 50-346 I. Introduction Paragraph 10 CFR 50.55a(g)(4) requires that thr,oughout the service life of a boiling or pressurized water-cooled nuclear power facility, components (including supports) which are classified as ASME Code Class 1, Class 2 and Class 3 shall meet the requirements set forth in the applicable Section XI Editions and Addenda of the ASME Boiler and Pressure Vessel Code to the extent practical within the limitations of design, geometry and materials of construction of the components.
l By letter dated"May 15, 1980, and supplemented by letters dated December,15,1980, March 31,1981, June 10,1981 and February 16, 1982, Toledo Edison Company (the licensee) proposed an Inservice Inspection Program to meet the requirements of the 1977 Edition of the ASME Code,Section XI through Summer 1978 Addenda. We performed an evaluation of the licensee's Inservice Inspection Program as referenced above.
Section 3 entitled " Weld, Support:, Compo,nents, and Bolting ,
Inspection Programs," and Section 4 entitled, " System Pressure Test Program," and provided our conclusions to the licensee in e208060332 820729 i PDR ADOCK 05000346 0 PDR
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a letter dated May 5,1982 from the Division of Licensing. The licensee detemined that confomance r t,. o.in Code require-ments was impractical and requested relief U om two requirements. -
We evaluated the licensee's bases for these detemination and provided our conclusions in the May 5,1982 letter.
In a letter dated June 22, 1982, the licensee determined that a third Code requirement was impractical and requested relief from the hydrostatic testing of ASME Code Class 2 components of the auxiliary feedwater (AFW) header replacement system. The licensee provided su'pporting technical infomation in a letter dated July 12 ,1982. -
II. Evaluation of Relief Request #3 The Davis-Besse operating license was issued on April 22, 1977.
Paragraph 50.55 a(g)(4)(1) requires that inservice examinations
- of components and system pressure tests..." conducted during the in.itial 120-month inspection interval, shall comply with the requirements in the latest Edition and Addenda of the ASME
- Code incorporated by reference in paragraph (b) of this section on the date 12 months prior to the date of issuance of the operating license, subject to the limitations and modifications listed in paragraph (b) of this section."
- . . . - - - - . - ... - - - .. . . . . - - - . . . . . . --1 The licensee has requested written relief from one (1) additional examination requirement that he has determined to be impractical in accordance with Paragraph 50.55 a(g)(5)(fii). We have evaluated the information in the referenced letters and have determined that the examination requirement, from which relief is requested, is impractical. We have further determined that life, property or common defense will not be endangered as a result of not performing these examinations. We have reached
- the conclusion that relief should be granted as authorized by 10 CFR 50 paragraph 50.55 a(g)(6) and that granting such relief is in the public interest giving due consideration to the burden upon the licensee if the requirements were imposed. The following paragraphs discuss detafis of the specific relief requert.
Auxiliary Feedwater Header and Lines to Steam Generator E-24-1 and E-24-2 (Relief Request (3)
Code Examination Requirement 1
, A. IWC-5223 " System Hydrostatic Test" requires-
. (a) The system hydrostatic test pressure shall be at least 1.10 times the system pressure, Psv, for systems.with Design Temperature of 200*F (93'C) or less, and at ,
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. . - . . . . . . . . ...u-...--.~.- r least 1.25 times the system pressure _, Psv, for systems with Design Temperature above 200'F (93*C). The system pressure, Psv, shall be the lowest pressure setting among the number of safety or relief valves provided for over pressure protection within the boundary of the system to be tested (e.g., 1050 x 1.25 = 1313 psig).
B. IWC-5230 " Temperature" requires:
(a) The system test temperature during a system hydro-static test in systems containing ferritic steel components shall meet' the requirements specified by fracture prevention criteria.
(b) In systems containing ferritic steel components for which fracture toughness requirements were neither I specified nor required in the construction of the
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components, the system test temperature shall be determined by the Owner. (e.g., The hydrostatic test temperature would be 130*F min to 200"F max.
which includes the NDTT + 60*F.)
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. . . .... .. .-,- . u ;= = = :-..-..=.- m e e C. IWA-5213(b) " Test Condition Holding Time" requires a system hydrostatic test hold time of 10 minutes for noninsulated systems or components.
D. Section XI, therefore, requires a visual examination during secondary hydrostatic test at a pressure of 1313 psig, temperature of 130' to 200*F with a 10 minute hold time.
Proposed Alternative Examination In lieu of the Code Examination Requirement, the licensee proposes to perform the follow'ing alternative examination:
A. Hydrostatically test each of the sixteen (16) riser subassemblies at 1313 psig for 10 minutes prior to installation.
B. Hydr'ostatically test the auxiliary feedwater header
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replacement system at 1.08 Po above operating pressure (Po) and at system operating temperature for a period of four hours.
Description of the Auxiliary Feedwater Replacement Header System .
i The original AFW piping will be cut inside the secondary shield wall and adjacent to the steam generator AFW nozzle, L -
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- -- - . .. . . . . . ...-.. ..;. - - - - .a . m which will be capped with a blind flange. Each replacement ARI system will consist of connecting pipe, an external ring header, and eight (8) riser subassemblies. Each riser will be connected to the ring header and new steam generator shell penetrations by bolted connections.
Licensee's Basis For Reouesting Relief The licensee requested relief from the system hydrostatic test after repair for the following reasons:
A. The nondestiuctive examinations (NDE) performed during the repair and the proposed alternative pressure test will demonstrate the structural integrity of the new piping system welds and the leak- tight integrity of the new flanged connections.
B. The hydrostatic test required by Section XI is a critical-path item that, if implemented, will delay 1
plant startup and require a substantial expenditure of manpower without a compensating increase in the safety and benefit.
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The licensee takes no exception to the Code NDE require-ments on the 94 additional welds and 8 supports which 11 are being added to the altered Auxiliary Feedwater Header b
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m and attached lines. These will be inspected to the require-ments of the construction Code which require' all welds to be radiographed and subjected to a surface examination using magnetic particle or liquid penetrant methods. To establish a baseline examination, 25% of the additional welds will be ultrasonically examined under Category C-F, Table IWC-2500-1 and 25% of the additional supports will be examined under Category C-C and C-E, Table IWC-2500-1 of A9tE Section XI,1977 Edition through Summer 1978 Addenda.
The licensee is also performing augmented ultrasonic exami-nations on 10% of the welds in piping less than 4 inches in diameter, which are exempted by IWC-1220 of Section XI.
In addition, the licensee proposes to perform two distinct hydrostatic tests:
A. Eachfof the riser subassemblies will by hydrostatically j
tested at 1313 psig for 10 minutes prior to installation.
- Therefore, 48 of the total of 94 new welds will be
! tested to the required test pressure. The ring header will be assembled in place from three curved pieces and cannot be meaningfully hydrostatically tested prior to installation due~to its configuration.
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B. The entire [StiE Class 2 system that is subject to the hydrostatic test will be pressurized to approximately 929 psig (1.08 times operating pressure) and 530*F (operating temperature at the steam generator) with a hold time of four hours. A visual inspection of all welds will be conducted per Section XI of the Code. The licensee notes that Section XI has provisions applicable to ASME Code Class I components for a reduction of pressure when the hydrostatic test is perfomed at elevated temperatures and proposes to use the same approach for the Class 2 system.
6 The licensee concludes that the proposed . reduced pressure hydrostatic test or.' the AS!!E Code Class 2 piping approximates the Class 1 requirements and offers a more meaningful evaluation of the system. In addition, approximately 48 man-hours (with no down time) is required to conduct this tes"t.
I The licensee estimates that a total of 2,287 additional man-hours and additional radiation exposure of 5 man-rem to numerous support personnel would be required to perform the hydrostatic test required by Section XI. Specifically, perfomance of the hydrostatic test specified in the Code would require the following:
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A. Blanking of 8 Code safety and 2 atmospheric dump valves per system.
MT B. Removal of bonnets and internals from check valves MS-726, 727, 734, 735 and AS-274. These valves would require new gaskets after testing.
C. Pin blocking all spring hangers on the main steam line.
D. Temporary piping and connections between the hydrotest pump and several locations in the system routed through radio-
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, active control areas requiring decontamination of temporary l piping before and after test.
E. Approximately 4.5 days delay in startup.
4 Staff Evaluation l:
We have ev11uated the information in the licensee's letters dated June 22, 1982 and July 12, 1982 which discuss the ramifications of perfonning the Code required hydrostatic g
j test. We have detennined that the following alternative i program proposed by the licensee is acceptable to maintain (1) the structural integrity of the 94 new welds and 8 supports, and (2) the leak-tight integrity of the new bolted connections as follows:
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. - -- -.. .. . . . .. . . . . . . . -. -.--- --c A. Performance of the required fabrication Code and Section XI nondestructive examination.
B. Performance of a hydrostatic test; prior to installation, on all riser subassemblies at 1313 psig and ambient temperature.
C. Performance of a reduced pressure hydrostatic test at approximately 929 psig and at operating temperature with a four-hour hold time.
Our' basis for this determination is as follows:
A. The riser subassemblies will be subjected to the requifed test pressure prior to installation.
B. The entire A91E Code Class 2 system that is subject to the hydrostatic test will be tested at approximately the conditions that would be required of an ASME Code Class 1
( system.
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C. The licensee is committed in the initial Inservice l
L Inspection Program to perform a hydrostatic test before L
- the end of the 10-year inspection interval in 1987.
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7-......-.- . - - - . . .. - - . . . .---.....-..---.-.~m Our evaluation has also detennined that requiring the Section XI hydrostatic test be perfonned at this time would result in a substantial additional manpower expenditure. -
additional occupational radiation exposure, and would delay plant startup and, therefore, would result in hardships or unusual difficulties without a commensurate increase in the level of quality and safety.
III. Conclusions We have concluded that relief from the hydrostatic test required by Section XI is justifiable because the alterna-tive program, proposed by the licensee, of nondestructive exartinations, pressure testing of the risers, and a reduced pressure test on the assembled system will provide an acceptable level of structural integrity. Relief may be granted based on our finding that certain sp,ecific require-ments of Section XI of the ASME Boiler and Pressure Vessel Code, 1977 Edition through Summer 1978 Addenda, are impractical to implement and would result in unusual difficulties without a compensating increase in the level of quality and safety. The granting of this relief is in the public interest giving due consideration to the burden upon the licensee if the requirements were imposed. We further conclude that granting this relief will not endanger life or property or common defense and security and is authorized by law.
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We have detemined that the granting of relief does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any sig- ,
nificant environmental impact. Having made this detennination, we have further concluded that granting relief involves an action which is insignificant from the standpoint of environmental impact and that an environmental impact state-
! ment or negative declaration and environmental impact appraisal need not be prepared in connection with the granting of this i relief.
We have concluded, based on the considerations discussed above, that: (1) because granting this relief does not involve a signif-icant increase in the probability or consequaces of an accident previously evaluated, does not create the possibility of an accident of a type different from any evaluated previously, and does not involve a significant reduction in a margin of safety, it does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) the activities authorized by the grant of relief will not be inimical to the common defense and security or to the health and safety of the public.
IV.
References:
. A. Licensee letter dated May 15, 1980 (Serial No. 616)
! B. Licensee letter dated December 15, 1980 (Serial No. 671)
C. Licensee letter dated March 31,1981 (Serial No. 702)
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D. Licensee letter dated June 10,1981 (Serial No. 715)
E. Licensee letter dated February 16,1982 (Serial No. 7.84)
F. Letter to licensee dated May 5,1982 from J. F. Stolz.
G. Licensee letter dated June 22,1982 (Serial No. 830)
H. Licensee letter dated July 12.1982 (Serial No. 838 )
Dated: July 29,1982 The following NRC staff personnel contributed to this Safety Evaluation:
M. Hum.
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