ML20212K996
| ML20212K996 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Diablo Canyon |
| Issue date: | 03/22/1977 |
| From: | PACIFIC GAS & ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20150F500 | List:
|
| References | |
| FOIA-86-391 NUDOCS 8608250158 | |
| Download: ML20212K996 (4) | |
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4 DIABLO CANYON
,s SPECIFICATION FOR SEISMIC RE-EVALUATION OF PIPING AND MECHANICAL AND ELECTRICAL EQUIPMENT FOR 7.5M HOSGRI EARTHQUAKE O
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March 23, 1977 8608250159 860001 PDR 501A PDR HOUOH36-391 Forktt,-39/
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DIABLO CANYON SPECIFICATION FOR SEISMIC RE-EVALUATION OF PIPING AND MECHANICAL AND ELECTRICAL EQUIPMENT
,FOR 7.5M HOSGRI EARTHQUAKE This document delineates criteria to be used in re-evaluation of Diablo Canyon piping, mechanical equipment, and electrical equipment for the seismic excita-tion of the postualated 7.5M Hosgri earthquake. The basic approach to be used in the re-evaluation will be to use the same procedures and criteria which were
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documented in the FSAR and which were used for the original Double Design Earthquake (DDE) analysis, but with the following specific changes:
c.
Input to re-evaluation will be based on 7.5M Hosgri spectra (floor response spectra determined using methods and criteria outlined in
" Specifications for Seismic Review of Major Structures for 7.5M Hosgri Earthquake"*). Due to the timing of availability of floor response spectra prepared to the referenced structural specification, spectra have been chosen for equipment and piping evaluation by augmenting and modifying spectra previously calculated. It is expected that these interim spectra will be equivalent to those determined by the detailed structural building analysis.
b.
Use Regulatory Guide L.61 damping except that 4% will be used for the N
reactor coolant loop.
Stress limits to be used will be those currently accepted for faulted c.
condition evaluations. Where material test data are available, actual material properties will be used.
d.
The Hosgri earthquake loads or stresses will be combined with normal operating loads or stresses.
The seismic re-evaluation of' equipment will be done by reanalysis of systems cnly where necessary. Reanalysis will be used in instances where.other equally cceeptable'but simpler methods do not show adequacy. Such equally acceptable methods include:
Comparison to original DDE analysis and comparison of increase in loads c.
to available margin.
b.
Comparison to analyses of similar equipment performed for different plants with acceptably high seismic input.
Generic qualification of types of equipment by demonstrating similarity c.
and adequacy of typical design.
- Reference 1:
"Diablo Canyon Specification for Seismic Review of Major Structures for 7 SM Hosari Earthquake," Februaz'f 2, 1977, Revised February 8, 19 7~/.
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i Where the above methods or reanalysis show inadequacy, modifications will be made to the equipment and further reanalysis done to show adequacy. The f llowing paragraphs outline in more detail the specific differences in criteria and methods from those presented in the FSAR.
1.
~neactor Coolant Loop The specific criteria and methods to be used in the seismic re-evaiuation of the reactor coolant loop are identical to those of the FSAR wi.th the following exceptions:
a.
The load combination to be considered is deadweight plus pressure, plus Hosgri earthquake.
b.
The structural damping used is 4% of critical.
1 The effect of torsion will be included by augmenting the horizontal-c.
response spectra in accordance with Reference 1.
s.
d.
Membrane stresses in primary component supports will be limited to 1.2 Sy (not to exceed 0.7 Su) and membrane plus, bending stresses will be limited to 1.8 sy (not to exceed 1.05 Su) based on elastic system analysis loads. The compressive loads in columns will be q
limited to 0.9 of critical buckling.
2.
Class A, B, and C Piping
- Other Than Reactor Coolant Loop The specific criteria and methods to be used in the seismic re-evaluation of the Class A, B, andrC piping, other than the reactor coolant loop, are identical to the criteria and methods of the FSAR with the following spec'ific differences:
a.
The load combination to be considered is deadweight plus pressure, plus Hosgri earthquake.
b.
The damping to be used will be 24 for pipes of less than 12" diameter and 34 for lines greater than or equal to 12" diameter in accordance with Regulatory Guide 1.61.
c.
The stress limits for Class B and C piping will be 2.4 Sh (in accordance with ASME Boiler and Pressure Vessel Code Case 1606).
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- These classes are defined in FSAR, Section 3.2.
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d.
Membrane stresses in piping supports will be limited to 1.2 Sy (not to exceed 0.7 Su) and membrane plus bending stresses will be limited to 1.8 Sy (not to exceed 1.05 Su) based on elastic system analysis loads. Compressive loads will be limited to 0.9 or critical
. buckling.
3.
Mechanical Equipment The specific criteria and methods to be used in the re-evaluation,of mechanical equipment are identical to the criteria of the FSAR with the following specific differences:
a.
The load combination'to be considered is deadweight plus pressure, plus Hosgri earthquake.
b.
The damping that will be used for flexible mechanical equipment will be 4%.
c.. The stress limits used for PGandE Code Class'II and III* components will be as follows; membrane stress will be limited to 2.0 S and membrane plus bending will be limited to 2.4 S.
d.
Operability of active equipment will be demonstrited by analyses or tests or by similarity to other equipment which has been appropriately qualified.
4.
Electrical Equipment The specific criteria and methods to be used in the seismic re-evaluation of electrical equipment are basically the same as those in the FSAR except for the use of the Hosgri spectra.
- Refer to FSAR, Section 3.2 for definition of PGandE equipment classification.
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