ML20011F647
| ML20011F647 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 02/22/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20011F646 | List: |
| References | |
| NUDOCS 9003070078 | |
| Download: ML20011F647 (3) | |
Text
U j
4
.pway[
o, UNITED STATES f_r 1
y
},
NUCLEAR REGULATORY COMMISSION T.
a wasHiNotow. o. c. rosss
- k.... + p j
l SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 32 TO FACILITY OPERATING LICENSE NO. NPF-62
{
CLINTON POWER STATION, UNIT NO. 1 i
I DOCKET H0. 50-461
1.0 INTRODUCTION
By letter dated June 30, 1089, the Illinois Power Company (IP), et al. (the licensecs) requested an amendment to Facility Operating License No. NPF-62 for the Clinton Power Station, Unit 1.
The proposed amendment would revise Technical Specification Section 1.8 to change the definition of core altera-l tion to exclude the normal movement of LPRMs or the undervessel replacement of SRMs, IRMs LPRMs, TIPS, or special moveable detectors from being considered a core alteration. Technical Specification Section 3.9.5 would also be revised to remain ccnsistent with the revised definition.
2.0 EVALUATION As currently defined in the Clinton Technical Specifications:
" CORE ALTERATION sball be the addition, removal relocation or movement offuel, sources,incoreinstrumentsorreactivltycontrolswithinthe reactor pressure vessel with the vessel head removed and fuel in the vessel. Normal movement of the SRMs IRMs, or TIPS, or special moveable detectors, is not considered a CORE ALTERATION.
Suspension of CORE ALTERATIONS shall not preclude completion of the movement of a component to a safe conservative position."
The definition of core alteration is used as a specific identified condition in the Applicability Section of a number of Technical Specification Limiting ConditionsforOperation(LCOs). These LCOs impose appropriate additional requirements and conditions on the plant.
The current definition of core alteration includes the normal movement of the local power range monitors (LPRMs) as being a core alteration.
- However, Clinton is a BWR/6 which incorporated certain design changes compared to earlier boiling water reactors. One of these changes is the introduction of a thimble / dry tube that houses the LPRM strings. The thimble is contained in a housing constrained by an assembly situated below the core plate and which provides a sealing surface under the reactor vessel. The thimbles are welded to the vessel and extend to the access area below the vessel. Thus, LPRMs may be replaced or removed from below the reactor vessel in the same manner as 900307o078 900222 S
PDR ADOCK 050t.0461 N>
P PDC a
[(
- s 2
Other incore instruments (SRMs, IRMs, etc.) witbout the removal of the reactor vessel head or movement of the fuel or other vessel intervals. The t.PRMs are only removed from the core when they are being replaced and they have no normal drive mechanisms.
Discussions with General Electric indicated that removal and insertion of an LPRM has a negligible impact on core reactivity.
' Based on the above discussion, the movement of the LPRMs would have no more impact on plant safety than the normal movement of the other intore instruments.
The current definition of core alteration defines the normal movement of the SRMs, IRMs TIPS, or special moveable detectors as not being a core alteration.
Various licensees have interpreted " normal" as including and not inclutting the undervessel replacement of the various moveable detectors.
The " normal" movement of the moveable incore detectors (SRMs IRMs. and TIPS) includes the withdrawal of the detector to a point well below the bottom of active fuel. With respect to the core, the configuration that exists when a moveable detector is withdrawn is essentially equivalent to that which exists when a moveable detector is withdrawn further and removed for replacement.
The removal of the moveable detectors for replacement, therefore, has no additional effect on core configuration or reactivity as compared to " normal" withdrawal.
In the specific case of the LPRMs, they have no normal drive mechanisn and are only moved when they are removed from the core for replacement. Although the availability of the moveable detectors would be effected differently in the two cases, the availability of the moveable detectors is supported by the Technical Specifications dedicated to ensuring the operability of the specific detector.
Based on the above discussion, there is no specific reason that the replacement of the moveable detectors should be restricted by the LCOs governing core alteration and therefore included in the definition of core alteration.
With the two modifications to the definition of core alteration discussed above, the words "incere instrument" should be removed from the first sentence that defines core alteration. This is necessary to remain consistent with the second sentence which will state that the movement of the SRMs, IP.Hs, LPRMs, TIPS, or special moveable detectors (the incore instruments) is not considered a core alteration.
Also to remain consistent with the revised definition, Technical Specification Section 3.9.5 should be revised to delete the note that provides an exception for incore instrumentation movement from the core alteration applicability.
The modification to the definition of core alteration will delete incore instrumentation movement from being considered a core alteration for all the Clinton Technical Specifications.
l Li i
L w
2 3
i
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves changes to requirements with respect to the installation or use of components located within the restricted area as defined in 10 CFR Part 20 and a change in surveillance requirements for the facility. The staff i
has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteriaforcateg)oricalexclusionsetforthin10CFR51.22(c)(9).to 10 CFR 51.22(b, no Pursuant assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
The staff has reviewed the proposed change to Technical Specification Section 1.8 to exclude the normal movement of LPRMs or the undervessel replacement of
_i SRMs. IRMs, LPRMs, TIPS, or special moveable detectors from being defined as a core alteration, and the proposed change to Technical Specification Section 3.9.5 to remain consistent with the revised definition.
Based on this review, the staff concludes that the changes are consistent with changes that have been made for other BWR-6 facilities and clarifies the applicability and scope of the definition of core alteration with respect to the movement of fuel, sources, or reactivity control components versus movement of incore instrumentation.
The NRC staff has concluded, based on its review of the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations and, (3) the issuance of this amendment will not be inimical to the common defense and the security nor to the health and safety of the public.
Prinicipal Contributor: John B. Hichnan, NRR/PDill-2 Dated: Eebruary 22, 1990 t
-