ML20083D657

Application for Amend to License NPF-29,revising Tech Spec 3/4.9.6.1 Re Refueling Platform for NF500 Main Hoist Grapple Mast to Permit Use of Either New or Existing Mast Design in Event of Operational Problems During Refueling Outage

ML20083D657
Person / Time
Site:	Grand Gulf
Issue date:	09/25/1991
From:	Cottle W ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20083D658	List: ML20083D657 ML20083D662
References
GNRO-91-00129, NUDOCS 9110010129
Download: ML20083D657 (10)

Text

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g Entergy Operations,inc.

- ENTERGY W T. Cottle Sep t ettber 25, 1991 U.S. Nuclear Regulat ory Co"*ilssion Mail Station Pl-137 Washington, D.C. 20555 Attention: Document Conttol Desk

Subject:

Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 1.icense No. NPF-29 Revision of Refueling Plat fot m Technical Specifications for NF500 Main lloist Grapple Most Proposed Amendment to the Opeinting Tleense ( PC01.- 91/19 )

GNRO-91/0012" Gentlemen:

Entergy Operations, Inc. has developed a proposed change to the Operating I.icense to revise the Technical Specifications (TS) associated with the Grand Gulf Nuclear Station (GGNS) refueling platfor m. These revisions would allow use of a new General Electric Model NF500 main hoist grapple inast which direct ly replaces the existing mast. The proposed charges would modify TS 3/4.9.6.1 to permit the use of either the new or existing _

mast design to provide ficxibility in the event of operational problems during a refueling outage. Surveillance Requirements on the main hoist interlock limits are also modified where necessary to nccount for the heavier weight of the new mast.

In accordance with the provisions of 10CFR50.4, the signed original of the requested amendment is enclosed. Attachment 2 provides the technical justification and discussion to support. the requested amendment. This ornendment has been reviewed and accepted by the Plant Safety Review Committee and the Safety Review Committee.

11ased on the guidelines presented in 10CFR50.92, Entergy Operat tons has concluded that this proposed amendment involves no significant hazards considerations.

09107191/SNh1CFl.R - 1 O ' 2 2' *to*2s o f: 0 C. ."s i. g'mnoo'cu osooo PDR m poot

September 25, 1991 GNRO-91/00129 Page 2 of 3 We wish to use the NF500 mast for fuel hand 11og during the next refueling outage. Accordingly, we are requestir s approval by March 1, 1992, so that the necessary arrangements may be completed prior to the beginning of-the outage.

Yours truly, ec:P r W WTC/KLW/mte attachments: 1. Affirmation por 10CFR50.30

2. GGNS PCOL-91/19 cc: Mr. D. C. liintz (w/a)

- Mr. J. L. Mathis (w/a)

Mr. R. B. McGehee (w/a)

Mr. N. S. Reynolds (w/a) l Mr.11. L. Thomas (w/o)

Hr. Stewart D. Ebneter (w/a)

Regional Administrator U.S. Nuclear. Regulatory Commission Region II 101 Marietta St., N.W., Suite 2900 Atlanta, Ceorgia 30323 Mr. P. W. O'Connor, Project Manager (w/a)-

Office of Nucicar Reactor Regulation U.S. Nucicar Regulatory Commission Mail Stop 13113 Washington, D.C. 20555 Dr. Alton B. Cobb (w/a)

State !!calth Of ficer State Board of Ilealth P.O. Box 1700 Jackson, Mississippi 39205 j G9107191/SNLICFLR - 2

9 BEFORE lilE l UNITED STATES NUCLEAR RE'3ULATORY COMMISSION LICENSE NO. NPT-29 l

DOCKET NO. 50-416 IN THE MATTER OF HISSISSIPPI 10KER 6 LIGitT COMPANY and SYSTEM ENERGY RESOURCES, INC.

and SOUTil MISSISSIPPI ELECTRIC POWER ASSOCI ATION and ENTERGY OPERATIONS, INC.

AfflMAIJD!i I am Vice Picsident, 1, W. T. Cot t le, being duly sworn, stat e that Operations GGNS of Entergy Operations, Inc. ; that on behalf of Entergy Operations, Inc., System Energy Resources. Inc., and South Mississippi Electric Power Association I am authorized by Entergy Opetations, Inc. to sign and (fle with the Nuclear Regulatory Commission, this application for amendment of the Operatiny, License of the Grand Gulf Nuc1 car Station; that I signed this application as Vice President, Operat fons GGNS of Entergy Operations, Inc.; and that the statements n.ade and the matters set forth therein are true and co: rect to the best of my knowledge, information and belief.

e O Qvtca V. T. Cottle STATE OF MISSISSIPPI COUNTY OF CLAIBORNE SUBSCRIBED AND SWORN TO before ae, a Notary Public, in and for the County and State obove named, this J $_ day of _ whm_ , 1991,

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l Attachment 2 to GNRO 91/00129 Page 1 of 7 A. SUBJECT  ;

1. NPE-91/03 Revision of Refueling Platform Technical Specificat ion for NF500 Main iloist Giappio Mast

2. Affected Technical Specifications

a. Specification 3/4.9.6.1, Refueling Platform, Page 3/4 9-8

b. Bases 3/4.9.6, Refueling Equipment, Page B 3/4 9-1 B. DISCUSSION

1. GGNS is requesting revisions to the Technical Specifications (TS) to allow use of a new main hoist grapple mast on the refueling platform. The new mast is a General Electric Model NF500 and incorporates design features which increase rigidity and improve performance relative to the existing mast (Model NT400).

2. It is also GGNS' intention to retain the ability to use the existing mast design if necessary in the unlikely event of major problems with the new mast. Accordingly, himiting Condition for Operation (hCO) 3.9.6.1 is modified to specify that either mast may be used to handle fuel assemblies.

3. The current NT400 mast is composed of four open frame type, telescoping triangular sections. It is being replaced by the new tubular mast assembly which has an increased sectfon modulus for I rigidity.

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4. The new mast meets or exceeds the requirements for the existing mast in all aspects, however the closed cylindrient tubing design of-the NF500 mast has a total dry weight of approximately 420 pounds more than the current NF400 mast. The additional weight necessitates changes te 9 o TS survelliance requirements which demonstrate operability of the refueling platform main hoist.

5. Surveillance Requirements 4.9.6.1.a.2, 4.9.6.1.a.3, and 4.9.6.1.b.2 are modified to include the main hoist interlock limits for the NF500 mast. New limits are required for interlocks on main hoist cable load due to the increased wofght of the NF500 mast. Interlock Ilmits for the NF400 mast are presented in parentheses to be used in the event that this mast is installed. A footnote is added to explain the applicability of these values.

6. Buses 3/4.9.6 is also being changed to include an additional statement clarifying the bases for the TS OPERAB1h1TY requirements.

7. Marked up TS and Dases pages reflecting the changes described above are included.

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Attachment 2 to GNRO 91/00129 Page 2 of 7

8. Note that Clinton Power Stat ion (CPS) han previously installed the new NF$00 mast design. The proposed changes are similar in part to those associated with thet installat!on and granted for CPS in Amendment 43.

C. JUSTIFICATION

1. The existing truss-st ilfened t riangular mast design is being j replaced by the tubular design in order to improve bridge and mast. performance. The new design is significantly less prone to mast bowing which could result in structural damage or grapple I misalignment. It also reduces the amount of potentfally contaminated pool water which may diip onto refueling bridge personnel as compared to t.he open f ramo design.

2. GGNS proposes that 1,00 3.9.6.1 be wonded- to allow use of either the NF500 or NF400 m'at. Cost considetations prohibit maintaining spares at the NF500 mast. In the unlikely event of a major problem with the mast, this ficxibility will allow installation of existing spares of the NF400 design to prevent potentially significant lengthening of a refueling outage. This also requires wording of the af fected Surveillance Requirements (described below) to include limiting interlocira values for each l

mast. A footnote is used to ensure that it is cicar which values apply to cach mast. l l

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3. Main Holst Interlocks a) The only design change having TS significance is the increased weight of the NF500 tubular mast sections reintive to the triangular mast. The additional weight requires that certain interlocks dependent upon total cable load be .

modified to ensure that protective features are activated l when required. Total cable load includes the submerged l

l weight of any suspended grapple loads (i.e. fuel assembly) and those portions of the mast supported by the cable and rect under the conditions considered for the interlock, b) The grapple engaged loaded interlock (TS 4.9.6.1.a.2) pievents raising the hoist when the hoist is loaded and the grapple is not fully engaged. The main hoist fuel loaded-interlock (TS 4.9.6.1.b.2) is provided to (1) initiate a Rod Control and information Syste:n (RCIS) control rod block when the hoist is loaded and located over the reactor vessel, and, (2) to prevent operating the hoist when the platform is l over the vessel with the hoist landed end a control rod is withdrawn.

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At tachment 2 to GNRO-91/00129 Fage 3 of 7 bimits for both of these interlocks are increased to 750 pounds. This value is calculated to be sufficient to ensure init iation of these interlocks when the weight of a  ;

channeled fuel bundle is applied to the hoist.  ;

c) The main hoist jam cutoff interlock (TS 4.9.6.1.a.3) is increased to 1430 pounds for the NF500 mast. This interlock '

is selected to limit the lif ting forces of the main hoist to ensure that excessive force is not npplied to a fuel assembly should it becomo stuck during handling opetations, ,

or to vessel internals should they hecome inadvertently

-c.. gaged. -The limiting lif ting force on vennel internals is 1800 pounds, well above the interlock. The allowable force on a fuel assembly is limited to 1250 jaunds. Adding the minimum submerged weight of the mast / grapple of 180 pounds yinids the limit of 1430 pounds to adequately protect against excessive fuel lif t ing for ce. An additions 1 8t wa statement is added to fully clarify the reason for shis operat inna1 limit.

No otiier interlocks or surveillance requirements are affected.

4. Accident Analyses _

a) Fuel llandling Accident in Containment The current design basis for the Fuel llandling Accident (Fila) in the UFSAR was evaluated for the ef fect of the proposed changes t o the mast. The Fila over the reactor vessel is discussed in Section 15.7.6. This accident assumes the drop of an irradiated fuel assembly into the core during refueling operations. .This analysis does not-consider the weight of the mast /grappIn assembly as part of the dropped weight due to the multiple failure. , quired to s cause a mast drop. Installation of the NF500 mast does not change the features protecting against a mast drop, and thus does not af fect this assumption in the Fila analysis. A scismic qualification of the platform with the new mast has also been completed and found to be within allowabic design limits. Therefore, the additional weight of the new mast has no impact on the existing analysis of the Fila over the reactor vessel.

b) Fuel llandling Accident in Auxiliary Building The UFSAR also presents an evaluation of a refueling accident over spent fuel assemblics in the auxiliary building in Section 15.7.4. This may be either the drop of a spent fuel assembly or of a nonfuel load. The NF500 mast will be used only on the refueling platform inside G9107191/SNh1CFhR - 7

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. Attachment 2 to P- 94 ;rT i29 Page 4 of 7

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. containment and not on the fuel handling platform in the-auxil!ary buj lding. Ilowever, this analysis was examined because tho' radiological source term derived here is also used for the inside centainment ace.ident analysis. - Also, i

.the tuel failure mechanisms are the same as those which would occur if the event happened over the containment fuel storage racks,.

c) Nonfuel Load Drop l The drop of a nonfuel weight of up to 1140 pounds onto spent fuel assemblies is based on the NUREG-0612 definition of a heavy load (the combined weight of a single fuel assembly and its associated handling tool) with the NF400 maet l Installed. This is reflected in limitations imposed by l TS- 3/4.9.7 which prohibits nonfuel loads of greater than l 1140 pounds from being moved over spent fuel assemblies'in 1 the storage rscks. The same NUREG-9612 definition for the NF500 mast would result in a heavy load va1ue of 1405 pounds, llowever, GGNS has conservatively elected to retain ]

the existing 1140 pound definition and associated TS limit.

To do otherwise would necessitate a reanalysis of the nonfuel drop event, plus a change to TS 3/4.9.7 and numerous other procedural and programmatic changes. Thus, nonfuci

-loads greater than 1140 pounds will continue to be prohibited from travel over spent fuel in the containment or spent fus) pool storage-racks. The existing analysis >

continues to bound credible nonfuel drop events. -

5. A design chango--is being implemented to accomplish the installation and necessary preoperational testing of the new mast. Prior to installation,_this design change was reviewed against the criteria of 10CFR50.59 and determined not to present

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an unceviewed safety question. The NF500 mast will be used for fuel-handling during_the next refueling outage if the proposed TS

changes are approved.

D. NO SIGNIFICANT HAZARDS CONSIDERATIONS The proposed changes would revise TS.3/4.9.6.1 associated with the containment refueling platform to all:w installation of the improved UE model NF500 main hoist grapple mast. The revisions would allow..

for use of either-the new mast or the existing NF400 mast design, and would provide the necessary interlock limits to be used in performing '

the Surveillance Requiremuuts for either mast..

The Commission has provided standards for determining whether a no significant hazards consideration exists as stated in 10CFR50.92(c).

A proposed amendment to an operating license involves no significant G914'191/SNLIC",R - 8

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Attachment 2 to GNRO-41/00129 Page 5 of 7 hazards consideration if operation of the facility in accordance with the proposed amendment would not: (1) Involve a significant increcse in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or dif ferent kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety.

Entergy Operations has evaluated the no significant hazards

,nsiderations in its request for a license amendment. -In accordance w.t 10CfR50.91(a), Entergy Operations is providing the analysis of

. proposed amendment against the three standards in 10CFR50.92:

1. No s.ignificant increase in the probability or consequences of an accident previously evaluated results from this change.

The only accident evaluations affected by the proposed changes are those associated with the Fuel llandling Accident analyses presented in UFSAR 15.7.4 and 15.7.6. The drop of a spent fuel assembly onto other spent fuel assemblics in either the reactor vessel or the upper containment storage racks is no more likely with the new design. The NF500 mast functions identically'to the old mast when grappling, lif ting, or moving a fuel assembly, it does not degrade platform design features such as grapple i

fail-safe on loss of air, dual lif ting cables, backup cable reel brake, and the grapple engaged loaded interlock, all of which serve to protect against a fuel drop event. It is more rigid than the pres tous mast design and, therefore, is less proro to most bowing. The consequences of dropping a fuel assembly are also unaf fect ed. Since the weight of the mast is not cons!dered in the Fila analysis, the increased weight of the NF500 mast has no impact on analysis results. The number of postulated fuel pins which fail as a result of the FHA is uncrfected since the energy imparted by'the dropped assembly is independent of the mast design, and mitigating systems will function as previously assumed.

I The drop of a nonfuel load onto spent fuel assemblies addressed in 15.7.4 is also no more likely as a result of this change.

While the combined weight of a fuel assembly and its associated l

handling tool, which is the definition of a heavy load by NUREG-0612 and the GGNS FsAR, is ining increased above the l current 1140 ' pound value enforced by TS 3/4.9.7, GGNS has conservatively elected not to increase this TS limit. This l ensures that the TS continues to prohibit movement of nonfuel y loads over spent fuel in excess of those-analyzed to be L acceptable. Should such a drop occur, the consequences, I therefore, remain unchanged. Retention of the ability to use the L

NF400 mast also does not present any changes since it is l

currently approved for use.

Thus, the probability or consequences of a previously analyzed accident are not significantly increased by the proposed change.

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Attachment 2 to GNRO-91/00129 m page 6 of 7

2. The; change would not create the possibility of a new or dif ferent -

kind of accident f rom aay previously analyzed.

No new failure modes are introduced as a result-of the proposed changes. The NF500 mast is intended as an exact replacement for the currently installed mast, and it is designed to match or exceed the strength and performance of the NF400 mast in all areas. No new fuel handling methods- or surveillance procedures will be necessary as a result of installation of the new mant.

The proposed limits will still ensure that the protective-interlocks are initiated as required. Limits on fuel travel-in ic11 directions are-unchanged. Retaining the ability to use the NF400 mast presents no new accident possibilities since this has already been analyzed for its current use.

- Therefore, there is no possibility of a new or different kind of accident from any previously analyzed.

3. This' change would not involve a significant reduction in the margin of safety.

Safet'y margin is established through the GGNS safety r nalyses as reflected in the Technical Specifications and Bases...The proposed ~ jam cutoff and hoist loaded-interlocks merely account for: the-incre sed weight of the mast and still provide _the intended protection as discussed-in the Bases. Other interlocks associated with the platform are unaf fected. No margins or assumptions related to the fuel bundle' drop' analyses ar3 changed and the new mast has the same single failure protection as the-old mast.

Following this -license amendment the allowed combined weigl.t of a fuel assembly;nnd its ' associated handling - tool, which is the definition _of- a heavy. load provided by NUREG-0612, is increased -

and would allow an increase in the current 1140 pound value enforced.by TS 3/4.9.7. GGNS has conservatively elected not to

-increase this TS limit. This ensures that'the TS continues to prohibit' movement of nonfuel loads over-spent fuel in excess of those analyzed to be acceptable and does not result in a reduction: to the margin of sa fety. ' Thus , the assumptions and margins of-the nonfuel drop accident evaluation are unaffected by this change.

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Attachment 2 to GNRO-91/00129 Page 7 of 7 Retaining the ability to use the NF400 mast is consistent with the existing-approved TS and presents no decrense in margin since the interlock limits will be appropriately set for the mast in use.

Thus..the proposed changes do not involve a significant reduction in tho' margin of safety.

Based on the above, Entergy Operations,.Inc. concludes that these proposed changes do not involve a significant hazards consideration.

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