ML20246C201
| ML20246C201 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 04/24/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20246C206 | List: |
| References | |
| NPF-62-A-018 NUDOCS 8905090287 | |
| Download: ML20246C201 (1) | |
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REACTOR COOLANT SYSTEM BASES 3/4.4.5 SPECIFIC ACTIVITY
' The limitations on the specific activity of the. primary coolant ensure that the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. thyroid and whole body doses resulting from a main steam line failure' out-side the containment during steady state operation will not exceed small. frac-tions of the dose guidelines of 10 CFR 100.
The values for the limits on speci-(
fic activity represent interim limits based upon a parametric evaluation by the NRC of typical site locations.
These values are conservative in that specific i
site parameters, such as site boundary location and meteorological conditions, were not considered in this evaluation.
The ACTION statement permitting POWER OPERATION to continue for limited time 1
periods with the primary coolant's specific activity greater than 0.2 micro-curies per gram DOSE EQUIVALENT I-131, but less than or equal to 4.0 microcurie.s per gram DOSE EQUIVALENT I-131, accommodates possible iodine spiking phenomenon which may occur _following changes in THERMAL POWER.
Operation with specific activity level.s exceeding 0.2 microcuries per gram DOSE. EQUIVALENT I-131 but-i less than or equal to 4.0 microcuries per gram DOSE EQUIVALENT I-131 must be restricted to no more than 800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> per year, approximately 10 percent of the unit's yearly operating time, since these activity levels increase the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> thyroid dose at the site boundary by a factor of up to 20 following a postu-lated steam line rupture.
The reporting of cumulative operating time over 500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> in any 6 month consecutive period with greater than 0.2 microcuries per gram DOSE EQUIVALENT I-131 will allow sufficient time for Commission evalt.a-tion of the circumstances prior to reaching the 800 hour0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> limit.
Information obtained on iodine spiking will be used to assess the parameters associated with spiking phenomena.
A reduction in frequency of isotopic analy-sis following power changes may be permissible if justified by the data obtained.
J Closing the main steam line isolation valves prevents the release of activity J
to the environs should a steam line rupture occur outside containment.
The surveillance requirements provide adequate assurance that excessive specific activity levels in the reactor coolant will be detected in sufficient time to take corrective action.
3/4.4.6 PRESSURE / TEMPERATURE LIMITS All components in the reactor coolant system are designed to withstand the effects of cyclic loads due to system temperature and pressure changes.
These cyclic loads are introduced by normal load transients, reactor trips, and start-up and shutdown operations.
The various categories of load cycles used for I
design purposes are provided in Section 3.9 of the FSAR.
During startup and shutdown, the rates of temperature and pressure changes are limited so that the maximum specified heatup and cooldown rates are consistent with the design assumptions and satisfy the stress limits for cyclic operation.
The operating limit curves of Figure 3.4.6.1-1 are derived from the fracture toughness requirements of 10 CFR 50 Appendix G and ASME Code Section III, Appendix G.
The curves are based on the RT and stress intensity factor NDT information for the reactor vessel components.
Fracture toughness limits and the basis of compliance are more fully discussed in FSAR subsection 5.3.1.5 entitled " Fracture Toughness."
CLINTON - UNIT 1 B 3/4 4-5 Amendment No.18 8905090287 890424 PDR ADOCK 05000461 p
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