ML20196E720
| ML20196E720 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 02/25/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20196E725 | List: |
| References | |
| NUDOCS 8803010259 | |
| Download: ML20196E720 (3) | |
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FNCLOSURE SAFETY EVALUATION RY THE OFFICE OF NUCLEAP PEACTOR REGULATION REQUEST FOR RELIEF FROM ASME SECTION XI REQUIREliENTS PEGARDING REPLACEMENT Or COMPONENT COOLING
,AND RECIRCULATION SPRAY HEAT EXCHANGERS i
SURRY POVER STATION UNITS 1 AND 2 DOCKET NUMBERS 50-?R0 AND 50-281 INTRODUCTION This report provides a safety evaluation of a reauest for relief from certain requirements of ASME Section XI pertaining to the replacement of component cooling and recirculation heat exchangers in Surry Units 1 and 2.
The request was submitted by Virginia Electric and Power Company (the licensee) in a letter dated July ?3. 1987. Additional infomation relative to the reauest was pro-vided to the NRC in a letter from the licensee dated November 13, 1907.
The bases for the requirements from which relief has been requested and for oranting)the relief are derived from the Code of Federal Regulations,10 CFR 50.55a(g (5). The subject regulations require that nuclear power facilities, such as Surry Units 1 and 2, conform with the requirements of Section XI of the ASME Boiler arid Pressure Vessel Code (ASME Section XII. ASME Section XI oro-vides requirements for replacement of components, su:h as the component cooling and recirculation spray heat exchancers.
10 CFR 50.55a(g)(6)(i) states that the Comission may grant relief from ASME Section XI requirements when they are detemined impractical for a facility, provided the Comission detemines that the granting of the relief will not endanger life or property or the comon defense and security and, giving due consideration to the burden that would be placed on the licensee if the requirements were imposed, that it is othervise in the public interest. The specific ASME Section XI requirements ' rom which relief has been requested, the evaluation and conclusions are described below.
ASME SECTION XI REQUIREMENTS In accordance with 10 CFR 50.55a(g), the edition and addenda of ASME Section XI applicable to Surry Units 1 and 2 are the 1980 Edition with addenda through Winter 1980, comonly abbreviated (80W80). ASME Section XI (80W80), Subsection IWA-7210, recuires that replacement components comply with the edition of the construction code to which the original component was constructed, or alterna-tively, later editions of the sane construction code.
The Surry Units 1 and 2 component cooling and recirculation spray system heat exchangers identified 1-CC-E-1A, -18. -1C, and 10, 1-RS-E-1A, -1B, -1C and
-1D, 2-RS-E-1A, -1B, -1C, and -10, were originally constructed to the require-ments of ASME Section III, Class C, 1968 Edition (68).
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RELIEF RE0 VESTED The licensee determined that replacement of the subject heat exchangers was necessary.
In seeking replacerents the licensee found that procurement of replacement heat exchangers constructed in compliance with the construction code to which the origiral heat exchangers were constructed or alternatively, later editions of the same construction code, was impractical.
Because the original construction code, ASME Section III Class C, referred to Section VIII of the ASME Code, the licensee requested perriission to use the 1986 Edition of Section VIII with addenda through the Winter of 1986(86W86) of the ASME Code for the construction of the subject replacement heat ex-changers.
BASES FOR RELIEF RE0 VEST The lic nsee provided the following reasons as the bases for their relief request.
1.
The original heat exchangers were manufactured to the requirements of the 1968 Edition of the ASME Code,Section III, Class C.
This Construction Code refers the manufacturer innediately to Section VI!! of the Code.
It is presumed that the referral was to the 1968 Edition of ASME Section VIII.
Manufacture of the heat exchangers to the original construction code is irroractical because the 1968 ASME Code Section VI!! requirements have been superseded by later editions and addenda.
Therefore, the licensee has reouested pennission to use the latest effective edition and addenda of ASME Section VIII, which would be the 1986 Edition with addenda through the Winter 1986.
2.
The heat exchanger manufacturing industry has maintained Section VI!! of 4
the ASME Code as the industry standard and many equipment manufacturers have not maintained their ASME Code Section III N-Stamp due to the pre-sent low businesi, demand. Thus, the number of heat exchanger vendors that are even qualified to manufacture these reolacement heat exchancers to a later edition of the ASME Code,Section III, is severely restricted.
3.
It is imoractical to impose the requirements of the ASME Section III Construction Code because the ASME Class C designation no longer exists and the heat exchangers would have to be manufactured to either ASME Class 2 or Class 3.
In addition, the use of ASME Section III as the con-struction code would imoose unjustified higher costs and longer procure-ment schedules.
The licensee has concluded that a vessel built to the 1986 ASME Code Section VIII.
Division 1 will meet or exceed the original requirements of the 1968 ASME Code Section III, Class C.
In addition, the licensee proposes to purchase the I
replacement heat exchangers from a vendor who has a quality assurance orogram in accordance with 10 CFR 50, Appendix B.
By imposing this additional require-ment, the licensee contends that the quality of the replacement component cool-l ing water and recirculation spray heat exchangers would meet or exceed the requirements of the original construction code.
a
's 3-EVALUATION _AND CONCLUSION The NRC staff's evaluation of the safety significance of the change proposed by the licensee is as follows:
1.
Based on an examination of the licensee's Drawings and the Manufacturers i
Data Reports (Form U-1) for the original heat exchangers, the staff accepts Class C (68)ginal Code applicable to the vessels was ASME Section III, that the ori l
2.
The staff detemined that the original ASME Section III, Class C (68) requirements were based primarily on ASME Section VIII requirements. The ASME Section VIII requirements are specifically referenced in ASME i
Section III, Class C (68).
3.
Based on a comparison of the design, fabrication and inspection require-ments of the original Construction Code with the ASME Section VIII, j
Division 1 (86W86) requirements proposed for the licensee's heat exchang-ers, the staff finds that there is no safety-significant difference.
4 Note: A detailed comparison of the requirements is described by the l
licensee in their letter to the NRC dated July 23, 1987.
f a.
The replacement heat exchangers will receive a U symbol rather than the N-Stamp the original heat exchangers received. These two certifications are similar; however, N-Stamp holders receive more intensive ASME review of their design, fabrication, and insptction procedures and N-Stamped heat exchangers receive a third party 11spection.
Based on the inherent conservatism of the ASME Code,Section VII requirements, the ASME review of the procedures for U-Stamping, and confomance to the quality assurance criteria of 10 CFR 50 Appendix B, the licensee's proposed alternative for procurement of the heat exchangers is considered to provide an accep-table level of quality and safety pursuant to 10 CFR 50.55a(a)(3)(1).
l 5.
If the ASME Code,Section XI requirements are imposed, the heat exchangers I
j would have to be manufactured to either ASME Code Section III, Class 2 j
or 3 rules. The manufacturer of the original heat exchangers has not re-4 tained the certification to N. Stamp heat exchangers.
Procurement of Section III heat exchanoers would result in higher costs and longer pro-curement schedules and is impractical.
Based on the impracticality of complying with the ASME Code,Section XI, require-i ments for replacement components, the burden on the licensee of complyino with the Code, and the licensee's proposed alternative, pursuant to 50.55a(g)l6)(1),
i relief from the Code requirements may be granted as requested. The staff finds j
that granting this relief will not endanger life or property or the comon de-j l
fense and security and is otherwise in the public interest.
In granting this i
relief, the staff has given due consideration to the burden upon the licensee i
that could result if the requirements were imposed on the facility.
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Dated:
February 25, 1988 Principal Contributor:
E. Sullivan W. Kleinsorge
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