ML19332D309
| ML19332D309 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/27/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19332D308 | List: |
| References | |
| NUDOCS 8911300337 | |
| Download: ML19332D309 (2) | |
Text
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UNITED $TATES
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NUCLEAR REGULATORY COMMISSION.
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION l
POLAR CRANE AUXILIARY HOOK OVER INCORE INSTRUMENT SEAL TABLE GPU NUCLEAR CORPORATION j
THREE MILE ISLAND NUCLEAR STATION. UNIT NO. 2 i
DOCKET NO. 50-320 INTRODUCTION l
As part of an international research effort, GPU Nuclear Corporation (GPUN),
I metallurgical samples from the reactor vessel (RV) port for obtaininglower head (refel the licensee, has submitted a Safety Evaluation re The NRC staff reviewed and subsequently approved this SER (reference B). To support the metallurgical sampling program, GPUN submitted an additional SER to use the polar crane (PC) auxiliary hook above the incore instrument seal table (reference C) to withdraw incore instrument strings. This activity will tske place after the defueling of the RV is complete. The verification of the defueling completion will probably not be complete.
EVALUATION The safety concern regarding using the PC auxiliary hook over the seal table is the potential for a drop of the load block. Neither the NRC staff nor the
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licensee could identify a mechanism by which a potential load drop over the i
seal table coul.1 reconfigure any remaining fuel or cause fuel to leak from the RV.
i A load drop could damage the seal table or the attached incore instrument j
tubes. Damage at or near the seal table would not cause a loss of reactor coolantsystem(RCS)waterduetothiselevation.
If forces were transmitted through tLe vertical runs of tubing, buckling and possible fracture could occur at the bend on the bottom of the 4.5 gpm per instrument tube and a maximum of six instrument tubes in the impact area. This results in a maximum leakage of 27 gpm.
i 01 The licensee's safety systems to make up potential RCS losses include two pathways for gravity feed from the borated water storage tank (BWST) and two reactor building recirculation systems. A single pathway from the BWST or a single recirculation pump system can supply 200 gpm. This makeup capability far exceeds any potential leakage from a load drop.
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i CONCLUSIONS The NRC staff has reviewed and evaluated the licensee's proposal to use the PC auxiliary hook over the incore instrusent seal table. Based on the above y
l evaluations, there is reasonable assurance that the health and safety of the public will not be endangered by this activity. This activity falls within i,
the scope of activities previously considered in the NRC staff's Progrannatic
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Environmental Impact Statement as supplemented.
REFERENCES l
a.
GPUN letter 4410-89.L-0085/048P dated August 18, 1989 from M. B. Roche to NRC with attached Safety Evaluation Report to Remove Metallurgical Samples from the THI-2 Reactor vessel.
b.
NRC letter J. F. Stolz to M. B. Roche, GPUN dated November 27, 1969 re:
Safety Ivaluation to Remove Metallurgical Samples from the TMI-2 Reactor
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Yessel.
c.
GPUN letter, 4410-89-L-0110/0509P dated October 26, 1989 from M. B. Roche to NRC Document Control Desk, " Safety Evaluation Report for the Use of the.
Polar Crane Auxiliary Hook Above the Incore Instrument Seal Table to J
Withdraw Incore Instrument Strings.
Principal Contributor: Lee H. Thonus
' Dated: November 27, 1989 i
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