ML20211C425
| ML20211C425 | |
| Person / Time | |
|---|---|
| Site: | Paducah Gaseous Diffusion Plant |
| Issue date: | 09/15/1997 |
| From: | Pierson R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| Shared Package | |
| ML20211C422 | List: |
| References | |
| NUDOCS 9709260203 | |
| Download: ML20211C425 (3) | |
Text
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ft UNITED STATES ij NUCLEAR REGULATORY COMMISSION s
e WASHINGTON. D,c. 3056H001 g
September 15.-1997 DOCKET:
70-7001 CERTIFICATE HOLDER:
United States Enrichment Corporation Paducah Gaseous Diffusion Plant Paducah, KY -
SUBJECT:
COMPLIANCE EVALUATION REPORT: APPLICATION DATED AUGUST 11,1997, COMPLIANCE PLAN ISSUE 3, AUTOCLAVE UPGRADES BACKGROUND By letter dated August 11,1997, the United States Enrichment Corporation (USEC) requested an amendment to the Certificate of Compliance for the Paducah Gaseous Diffusion Plant (PGDP). The request it to revise Compliance Plan issue 3, Action 7 to extend the completion date two months from August 31,1997 to October 31,1997 and to revise the required modification.
DISCUSSION One channel of the C-360 (Toll Transfer and Sampling Facility) Autoclave High Pressure isolation and Steam Pressure Control Systems becomes disabled if the instrument air system f ails. The channels are relied upon for initiating containment on a high pressure indication. The pressure switches for the A channcI of these systems receive a pneumatic signal from a pneumatic pressure transmitter. The signal air to the pressure transmitter is supplied by the instrument air system, if the instrument air system should develop a leak, the pressure transmitter would not be capable of providing the correct output signal and the pressure switches would not be capable of performing their intended safety function.
Compliance Plan issue 3, Action 7 called for a low instrument air switch to be installed that would initiate containment upon loss of instrument air. USEC conducted additional j
evaluations of the system and determined that the modification specified in the Compliance Plan may not be the best approach. USEC is now proposing to install mechanical electrical pressure switches to directly read autoclave pressure.
insta!!ation of a low instrument air switch to initiate containment upon loss of instrument air would result in putting the autoclaves into containment in the event of loss of air as a precaution, since one of the channels could not perform its safety function, and not because'of a real need for activation of the safety system. The existing TSRs allow for the current cycle to be completed when one channal is inoperable to prevent potential freezout of the uranium hexafluoride in the pigtail. The addition of the low instrument air switch would not allow for the completion of the current cycle and could result in uranium hexafluoride solidifying in the pigtail.
The mechanical electrical type pressure switch does not rr.ly on instrument air to perform its safety function and is similar to those used in Channel B. The switches will failin a 9709260203 970915 3 PDR ADOCK 07007001~
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2 s f2 condition upon loss of ci:ctricci pow:r. With the inst:llation of th:ss switch:s, neither safety channel will rely on instrument air, thereby removing a possible failure mode.
The installation of the mechanical-electrical switches is an improvement over the
. installation of the low instrument air switches as discussed in the Compliance Plan. The new pressure switches will correct the problem of losing a channel upon loss of instrument
- air, tsSEC proposes to extend the completion due date for this item to October 31,1997. The modifications would then be made at the same time as the modifications required by Compliance Plan issue 3, Action 4. This would allow the C 360 operations to be shut down once while the rnodifications are being made instead of twice. The Justification for Continued Operation will continue in force. There is redundant instrumentation to initiate containment upon a high pressure indication. One channel contains a pressure switch which is not dependent on instrument air. This is sufficient until the new switches are installed.
USEC has provided the page changes to the Compliance Plan to reflect installation of the new switch and the new completion date.
ENVIRONMENTAL REVIEW lssuance of an amendment to Certificate of Compliance GDP 1 to revise the Compliance Plan to extend the completion date and to ravise the autoclave modification will not impact the environment. The change is subject to the categorical exclusion provided in 10 CFR 51.22(c)(1 P' Therefore, neither an environmental assessment nor an environmental impact st' ent is required for the proposed action.
CONCLUSION Installation of the mechanical-electrical switches ir, place of the low instrument #r switch will prevent unnecessary initiation of containment and will adequately address the problem of loss of instrument air. The staff recommends that the Compliance Plan page changes be approved.
The Region lli inspection staff have no objection to this proposed action, i
Princioal Contributor Merri Horn DISTR!BUTION: (Control No. 280S)
Docket 70 7001 NRC File Center PUBLIC Rill KO'Dnen, Rlli NMSS r/f NMSS dir, ofc, r/f FCSS r/f FCOB SPB r/f
- PHiland, Ritt 4 Se e__ (ht um g.
OFC SPB h
SPB SP_B f, _
Sh NAME MHorn:ij DHoadley art n R rson l
r l
DATE 6A797 4/397 4 O/97 3/ U/97
^
C = COVER E = COVER & ENCLOSURE N = No COPY OFFICIAL RECORD COPY l
2 d:fa condition upon loss of el ctrical powsr. With ths instellstion of thess switches, hgither sofoty channel will rely on instrument air, thereby removing a possible f ailure mode.
Th(installation of the mechanical-electrical swnches is an improvement over the instat-tion of low instrument air switch as discussed in the Compliance Plan. The new pressur switches will correct the problem of losing a channel upon loss of instrument air.
USEC propo s to extend the completion due date for this item to October 31,1997. The modifications ould then be made at the same time as the modifications required by Compliance Plan ssue 3, Action 4. This would allow the C-360 operations to be shut down once while t e modifications are being made instead of twice. The Justification for Continued Doeration in continue in force. There is redundant instrumentation to initiate containment upon a hi pressure indication. One channel contains a pressure switch which is not dependent instrument air. This will be suf ficient until the new switches are E
..dtalled.
USEO has provided the page c nges to the Compliance Plan to reflect installation of the I
new cwitch and the new complet' n date.
\\
EbiVIRONMENTAl, REVIEW i:J;uance of an amendment to Certificate Compliance GDP-1 to revise the Compliance Plan to extend the completion date and to re 'se the auteciave modification will not impact the environment. The change is subject to tha ategorical exclusion provided in 10 CFR 51.22(c)(19). Therefore, neither an environment assessment nor an environmental y
impact statemera is required for the proposed actio CONCLUSION Installation of the mechanical-electrical switches in place o he lo'N instrument air switch will prevent unnecessary initiation of containment and will ad' uately address the problem eiloss of instrument air. The stMf recommends that the Compli ce Plan page changes be approved.
The Region ill Inspection staf t have oc objection to this proposed action.
Pnncicol Contributor Merri Horn o
QBTRIBUTION: (Contto! No. 290S)
=
Docket 70-7001 NRC File Center PuBLIC Rill KO'Brien, Rlli NMSS r/f NMSS dir c.fc. r/t FCSS r/f FCOB SPB r/f
- PHiland, Rill II (SPB h
SPB SPB OFC SPB NAME Horn:ij IHoadley DMartin RPierson 4
k h/97 oATE 7 /7/97
//97
/ /97 C = COVER E = COVER & ENCLOSURE N = No COPY OFFICIAL RECo.:D Co?Y
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