ML20073P639
| ML20073P639 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 05/16/1991 |
| From: | Sieber J DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9105220155 | |
| Download: ML20073P639 (5) | |
Text
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Nuclear Regulatory Commission Attn:
Document Control Desk Washington, DC 20555
Reference:
Beaver Valley Power Station, Unit No. 1 Docket No. 50-334, License No. DPR-66 Request for Temporary Waiver of compliance This letter provides our request for NRC approval of a temporary waiver of compliance from the requirements of Technical Specification 3.9.2.
Additional details supporting this request are located in the enclosure which addresses the current understanding of the level of detail required with respect to requesting a temporary waiver of compliance.
This request has been reviewed by our Onsite Safety Committee (OSC) and is determined to be safe.
This request is characterized as a regional waiver of complianco since the relief is temporary and non-recurring such that a permanent license amendment is not appropriate.
Questions regarding this submittal may be directed to members of ny staff.
Very truly yours,
.k -
b.D. Sieber hVicePresident Nuclear Group Enclosure cc: Mr. J.
Boall, Sr. Resident Inspector Mr.
T.
T.
Martin, NRC Region I Administrator Mr.
A.
W.
DeAgazio, Project Manager Mr. M.
L.
Bowling (VEPCO)
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1 1: valuation Supporting a Tempor ary Faiver of compliance (Inoperable Source Range Detector - Technical Specification 3.9 2) 1, 11oaver Valley Pcwer Station - Unit t'o. 1 l
9 l
1.
Discunn the requirements for which a waiver is requested:
This in a
temporary uaiver of compliance concerning two j
mopects of the source range detector operability requirement.
Th:
first aspect of Technical Specification l
3.9.2 requiren two nource range monitoro each with I
continuous visual indication in the control room and one I
audible indication in the containment and control room.
A l
temporary waiver of compliance in requented to allow the une i
of a
portable submersible source range detector in place of
]
inoperabic cource range detector N31 for the purpose of fuel loading.
This portable nubmersible detector would have a visual indication in the containment only and would be continuously monitored by an individual in conutant i
communication with the control room and the manipulator crane operator.
The requirements of this specification are applicable in Mode 6
during core alterationc or positive 4
i reectivity changco.
The necond aspect concerns having only one operable cource l
range detector during movement of the upper internalo.
Our present interpretation of
" Core Alterations" includes movement of the upper internals and an such Technical l
Specification 3.9.2 remains in affect.
Placement of the upper internals in the reactor vennel cannot be done with the portable nource range monitor ponitioned in the vennel.
Therefore, this waiver is also needed to allow une of the
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portable neutron flux detector while reloading the fuel, i
after which the detector would be removed from the vessel.
l The upper internals would then be positioned in the venuel with only tho one operable source range detector.
The water level in the reactor vessel cavity would then be lowered, the retracted incore thimbles would be inserted into the i
core to reduce the radiation fiold under the reactor vessel thun permitting access to icpair the cource range detector.
l 2.
Discuns the circumstances surrounding the nituation j
including the need for prempt action, and why the nituation i
could not have been avoided:
The nource range detector failed after the core was completely off loaded.
The incore flux thimbles are l
retracted from the reactor vencel as part of normal l
refueling sequence to prevent discharge during fuel i
movement.
Due to this evolution, the radiation field in the area of the source range detectorc in 3R/hr at 20 feet and i
is estimated to be 50R/hr at the location of the inoperable cource range detector.
Repair activities would require a
t i
}
Temporary Waiver of Compliance 2
Page 2 team-of four plant personnel working three eight hour shifts at the detector location.
The use of shielding in the area of the inoperable detector is considered highly impractical
(
due to the size and layout of the area in which the inoperable detector is located.
This radiation field is too high to conduct repair activities with the-incore flux thimbloc withdrawn and they cannot be re-inserted fully into the vessel until the fuel is reloaded.
Regarding two operabic detectoro during placement of the upper internals; this cannot be accomplished while the submersible detector is placed inside the reactor vessel.
The remaining operable source range detector will be relied upon when placing the upper internals into the reactor vessel.
Therefore, plant refueling activities cannot proceed without a temporary waiver from the requirements of Specification 3.9.2.
3.
Discuss compensatory actions (if any):
A portable submersible detector will be used to perform the flux monitoring function in place of the ineperable source range detector.
The monitoring of neutron flux via the temporary detector will be performed locally in containment by plant personnel.
Constant communications will be maintained during core alterations or positive reactivity changes between the plant personnel monitoring neutron flux in containment and control room personnel.
Connecting the temporary detector to allow control room indication is not practical as it is a-self-contained system.
A reliable indication of neutron flux will be obtained by plant personnel who are monitoring detector response locally on the containment-operating doch and in constant communication with the control room.
No additional compensatory actions will be performed during placement of the upper internals since this involves no positive reactivity changes and the operable source range detector is availabic to monitor the core.
4.
provide a
preliminary evaluation of the safety significance and potential consequences of the proposed request:
The function of the source range detectors is to provide direct neutron flux monitoring of the-core to detect positive reactivity additions which would result in a loss-of the required shutdown margin for U de 6.
The portable detector will provide neutron flux monitoring in place of the inoperable source range detector during fuel movement, thus assuring core monitoring at a level consistent with Technical Specification 3.9.2.
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i 1
4 Technical Specification 3.9.2 Temporary Waiver of Compliance page 3 During placement of the upper internals, one operable source range detector adequately provides the required core flux monitoring.
This evolution will not result in a positive reactivity addition, therefore, the required shutdown margin will be maintained.
5.
Discuss justification for the duration of the request It is requested that approval of this temporary waiver be granted as soon as possible and remain in effect for up to 7 days or until the inoperable detector has been repaired and in verified operable.
This will allow the core to be
- refuoled, the upper internals installed, the incore detector thimbles inserted, and the source range detector repaired.
6.
Provide a basis for the conclusion that the request does not involve a significant hazards considerationt The first aspect of the temporary waiver will allow use of a submersible portable flux monitor when refueling the core.
Using this monitor will not increase the probability of an accident previously evaluated.
The required core shutdown margin is assured through maintaining the required refueling bcron conentration per T.S.
3.9.1 and control rods fully inserted in the fuel at all times.
The required shutdown margin is sufficient to accomodate these activites and 4
preclude a criticality event during the tofueling.
No changes are being made that would act to increase the probability of a
positive reactivity addition event.
Therefoto, there will be no impact on any accident previously analyzed and no signficant hazard created.
The second aspect of the temporary waiver, which allows
' installation of the upper internals with one operable source range
- detector, will not increase the probability of an accident previously evaluated.
The operable source range detector N32 will provide the required continuous visual indication in the control room and audible indication in the containment. and control room.
The installation of the upper internals with one source range detector operable will not increase the probability of a
pooltive reactivity event occurring in the core.
Therefore, there will be no impact on any accident previously analyzed and no signficant hazard created.
7.
Provide a' basis for the conclusion that the request does not involve irreversible environmental consequences:
The portable monitor will provide adequate neutron flux monitoring to ensure the core is loaded correctly.
There is no credibic mode of malfunction by which the use of this submersible flux monitor can affect the conclusions of the previously analyzed accidents or create a new accident.
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4 Technical Specification 3.9.?
i Temporary Waiver of Compliance l
Page 4 l
The offsite dose analyses and accident analyson are not i
affected by thin temporary waiver.
11o radioactive release to the environment and no change in the core flux levels is expected.
The waiver does not provide any changes to the core licensed power level or act to increase radioactive offluents.
Therefore, this requent for temporary waiver doon not involve irreversible environmental consequences.
i i
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