ML17342A485
| ML17342A485 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 02/13/1985 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML17342A484 | List: |
| References | |
| NUDOCS 8604290391 | |
| Download: ML17342A485 (12) | |
Text
ENCLOSURE SAFETY EVALUATION REPORT ON REQUESTS FOR RELIEF FROM INSERVICE INSPECTION REQUIREMENTS FLORIDA POWER AND LIGHT COMPANY TURKEY POINT UNITS 3 AND 4 DOCKET NOS. 50-250/50-251 I.
BACKGROUND By letter dated December 6, 1985, Florida Power
& Liqht Company (the licensee) requested relief from certain inservice examination requirements of the 1980 Edition through Winter 1981 Addenda of Section XI of the ASME Code at Turkey Point Units 3
& 4 for the second inspection interval.
The relief requests submitted by the licensee are numbered 13 and 14.
This report provides an evaluation of the licensee's
- requests, supporting information, and alternative examinations or tests, as well as the staff's bases for granting or denying the requests pursuant to 10 CFR 50.55a(g).
The relief requests are evaluated below.
II.
EVALUATION OF RELIEF RE UESTS 1.
Relief Re uest ¹13 Ultrasonic Calibration Blocks for Class 1, Main Coolant Pi in
- Welds, Code Examination Cate pries B-J
& B-F Code Re uirement The basic calibration blocks shall be made from material of the same nominal diameter and nominal wall thickness or pipe schedule as the pipe to be examined.
(Paragraph III-3410).
Bb0429039i 8b0423 H PDR ADOCK 05000250 9
P DR/
Code Relief Re uest Relief is requested
.from compliance with Appendix III, paragraph III-3410, for those welds on the Turkey Point Units 3 5 4 main coolant piping welds.
Existing piping consists of three (3) sizes:
~Thi k
R 27.5" 29" 3] II 2.25" to 2.5" 2.7" to 2.9" 6ll to 3 3II The piping system also consists of two (2) materials within the three (31 sizes:
Pipe A376 TP 316, Fittings A351 GR CFSM Pro osed Alternative Examination
( I)
Perform the Code required examinations with the proposed ultrasonic calibration blocks.
(2)
The alternative examinations provide an assurance of acceptable quality and safety.
Licensee Basis for Relief (I)
III-3410, as written, would require six (6) different calibration blocks representing both material types in the three sizes.
(2)
Florida Power
& Light Company proposes to continue to use three (3) calibration blocks:
(I)
A351 GR CFSM, 27.5" ID x 3" wall (2)
.A376 TP 316, 29" ID x 2.6" wall.
(3)
A376 TP 316, 29" ID x 2.4" wall (3)
The small difference in diameter will not affect the ultrasonic examination.
ASME Section V, Article 5 has allowed a range of sizes, particularly in the case of diameters greater than 20 inches.
~I (4)
The small difference in wall thickness is within piping tolerances for nominal wall and will not affect ultrasonic examination because metal path calibration techniques are used.
Ultrasonic indications are resolved by full scale plotting based on pipe actual wall thickness.
(5)
The three proposed blocks have been in use since the Plant was built, their continued use would tend to provide consistent results.
Staff Evaluation The proposed ultrasonic calibration blocks were used at the facility and met the requirements of ASIDE Section V Code being followed at Turkey Point Units 3
8 4.
- However, an update to the current Section XI Code has necessitated this relief request.
The diameters of the existing piping and the proposed ultrasonic calibration blocks range from 27.5 in. to 31 in. and 27.5 in. to 29 in., respectively.
The small difference in diameter between the existing piping and the proposed calibration blocks will not affect the ultrasonic examination.
Article 5 of the ASME Section V Code allows a calibration block to have essentially the same curvature as the test surface for materials with diameters greater than 20 in.
The thicknesses of the existing piping and the proposed ultrasonic calibration blocks range from 2.25 in. to 3.3 in. and 2.4 in. to 3 in., respectively.
The small difference in thickness between the existing piping and the proposed calibration blocks will not affect the ultrasonic examination.
The licensee calibrates based on the metal path and reports ultrasonic indications based on the actual wall thickness.
The proposed calibration blocks have been used to establish the material history and should continue to be used for ultrasonic testing of welds so that past and future results can be correlated.
Based on the staff's evaluation and the licensee's discussion
- above, the staff concludes that the Code requirements are impractical.
It is further concluded that the alternative examination discussed above will provide necessary added 'assurance of the piping welds'tructural reliability.
Therefore, the following apply:
(a)
Relief should be granted from paragraph III-3410 of Appendix III as requested.
(b)
The licensee should continue to use the proposed ultrasonic calibration blocks for the subject piping welds.
2.
Relief Re uest ¹14, Ultrasonic Calibration Block for Class 2, Main Steam Reducer to Nozzle Pi in
- Melds, Code Examination Cateqor C-F, Code Item Number C5.21
4
Code Re uirement The basic calibration blocks shall be made from material of the same nominal diameter and nominal wall thickness or pipe schedule as the pipe to be examined.
(Paragraph III-3410).
Code Relief Re uest Relief is requested from compliance with Appendix III, paragraph III-3410, for those welds on the Turkey Point Units 3 8 4 main steam reducer to nozzle welds utilizing a calibration block made from a material of the same nominal diameter and nominal wall thickness or pipe schedule as the pipe being examined.
The following reducer to nozzle welds are affected:
Unit Weld Identification Unit Wel d Ident ificati on PTP-3 26"-MSA-2301-IA 26"-MSB-230?<<1A 26"-MSC-2302-1A PTP-4 26"-MSA-2401-1A 26"-MSB-2402-1A 26"-MSC-2403-IA See Figure No. I in the relief request for typical configuration and material specifications for each identified weld.
Pro osed Alternative Examination
( 1)
Perform the code required examinations with the proposed ultrasonic calibration block.
(2)
Perform the examinations per the ISI Table INC-2500-1.
Licensee Basis for Relief
( I)
Appendix III, paragraph III-3410, as written, would require a ultrasonic calibration block to essentially match either the nozzle or the reducer.
(2)
Configuration of the nozzle extension piece adjacent to the subject welds prohibit ultrasonic examination of the code required volume from the nozzle side.
(3)
Florida Power 8 Light Company feels that procurement and fabrication of a calibration block, solely for compliance with III-3410 of Appendix III for the six (6) nozzle to reducer welds will require large expenditures of manhours and cost with essentially no compensating increase in plant safety.
(4)
The small difference in diameter (31" vs 26") will not affect the ultrasonic examination.
ASME Section V, Article 5 has allowed a
range of sizes, particularly in the case of diameters greater than 20 inches.
(5)
In lieu of utilizing a calibration block fabricated from the reducer
- material, (A-105 Class II, 1.5 inch wall) Florida Power 8 Light Company proposes to use a calibration block of 26 inch diameter, with a thickness of 1.5 inches wall material of suitably similar specifications with identical tensile properties and metallurgical structure.
(6)
The extent of examination volume achieved ultrasonically, coupled with the surface examination and the system pressure tests provide assurance of an acceptable level of quality and safety.
Staff Evaluation Ultrasonic examination is to be performed from the reducer side of the reducer to nozzle welds.
The diameters of the reducer, at the reducer to nozzle welds, and the proposed ultrasonic calibration block are 31 in.
and 26 in., respectively.
The small difference in diameter between the reducer and the proposed calibra-tion block will not affect the'ltrasonic examination.
Article 5 of the ASNE Section V Code allows a calibration block to have essentially the same curvature as the test surface for materials with diameters greater than 20 in.
The thicknesses of the reducer, at the reducer to nozzle welds, and the proposed ultrasonic calibration block are both 1.5 in.
In lieu of utilizing a calibration block fabricated from the reducer material, the licensee proposes to use a calibration block of material of suitably similar specifications with identical tensile properties and metallurqical structure.
This is allowed by paragraph III-3411 (c) of the Code.
Based on the staff's evaluation and the licensee's discussion
- above, the staff concludes that the Code requirements are impractical.
It is further concluded that the alternative examination discussed above will provide necessary added assurance of the reducer to nozzle piping welds'tructural reliability.
Therefore, the following apply:
(a)
Relief should be granted from paragraph III-3410 of Appendix III as requested.
(b)
The licensee should use the proposed ultrasonic calibration block for the subject reducer to nozzle piping welds.
III. CONCLUSIONS The staff has determined that relief from the inservice examinations required by Section XI is justifiable.
The alternative examinations, as proposed by Florida Power and Light Company, will provide an acceptable level of structural integrity.
Relief may be granted pursuant to paragraph 10 CFR 50.55a(g)(6)(i) based on our finding that certain specific requirements of the Code are impractical, and the alternative examination imposed will provide an acceptable level of quality and safety.
The granting of this relief is authorized by law and will not endanger life or property or the common defense and security, and is otherwise in the public interest giving due consideration to the burden that could result if the requirements were imposed on the facility.
Dated:
February 13, 1985 Principal Contributor:
S.
Lee
-0 e