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Before an outage, it is essential to review the parts requirements for both stock (warehoused) and non-stock (direct purchase, just-in-time, stock supplements) parts to support routine work and planned work. Routine work is defined as work associated with the normal disassembly,

inspection, and reassembly of the turbine-generator. Parts to support routine work are itemized in Table 2-12.

Pre-Outage Planning and Bidding Table 2-12

Parts and Consumables Used to Support Routine Work

Parts Consumables

Gaskets Rags Sealants Fish paper

O-rings Oil adsorption

materials Adhesives Shop ticket holders Bolts Triple-boiled linseed oil Markers Plywood

Washers Pails and buckets Liquid nitrogen Pallets

Nuts Welding cloth Dry ice

Bushings Safety wire Fuse wire

Bearings Shim stock Tongue depressors Valve components Paraffin wax Oak cribbing

Planned work is work that is not part of the normal disassembly and reassembly process. Planned work can be as simple as designating the replacement of packing as required or as complex as a complete rotor change-out. Reviewing historic usage is one step in evaluating the status of a plant’s stock level to match outage requirements. A review of non-stock parts used during the last outage coupled with its work scope is also beneficial. It is important to evaluate the status of critical items at a timely interval because warehouse stock levels are reduced to meet utility economic guidelines, and part ordering is often dictated by just-in-time delivery cycles. Missing a simple gasket can cause delays at the wrong time during unit assembly.

Desktop or LAN-based databases introduced in Section 2.1.1 are an appropriate tool to assist in reviewing parts. Resident databases allow the reviewer access to information that may be queried to meet a specific review question. The master parts database should contain all identified parts associated with the turbine-generator. This includes both stocked and non-stocked items. The master parts database should contain as much history of part use as possible.

The location of use is the second database necessary for parts review. The part use location database can be constructed with information available from unit construction or acquired through time. The information can be organized in a variety of formats. One format used by an OEM provides the location information identified by both numeric and location descriptive coding. Regardless of the method used, the coding or grouping location information becomes the basis for querying the database to determine part requirements. Figure 2-12 shows one method of coding or grouping part location information.

Pre-Outage Planning and Bidding

Figure 2-12

Part Location Information

It is useful to build the part location database (catalog of use) with grouping level descriptions that will aid in planning as well as in finding associated parts. One method is to group and divide parts into four levels, three of which identify the location of use and the fourth identifies the part.

In most cases, this will provide a sufficient breakdown to find a part by beginning at the highest level and “drilling” to the part itself. The drilling process excludes all parts not associated with the higher-level item. It also helps in identifying all like parts used within a specific section.

Figure 2-13 visually depicts this breakdown.

Figure 2-13

Four-Level Part Location Hierarchy

"Section” is the highest level of identification within either the turbine or generator. The

“subsection” is the next logical breakdown when observing the makeup of the section.

“Location” is the third descriptor and might not always be needed. The last item is the

“common” name associated with the part. The common name may be a single “nickname” or

Pre-Outage Planning and Bidding

multiple nicknames normally used for that part by the utility. A nickname is always included.

For example, one commonly used part is one that the OEM identifies as the outer stationary sealing component for the rotating row of buckets. This item is called a steam deflector;

however, this item is often called simply a “spill strip.” So, spill strip is used as the familiar part identifier or nickname.

The OEM often provides some form of part use information. This information can then become the seed or foundation for the parts catalog database. The information provided by the OEM might not provide sufficient breakdown or organizing details, so grouping levels are added to the part use location information. The combination of this information now provides a familiar and useful tool. The following are two examples of the grouping structure.

The database contains all the relationship information for each part location. Within the database, these are the fields for each record. The record is all of the information that describes a part.

Coded in the database is the ability to display only the appropriate information, limited by the items selected to be queried.

As in Figure 2-13:

1. If HP is selected as the section:

• N-1, N-2, and shell (or all subsections associated with HP) would be displayed as subsection choices for further drilling.

• No other subsection is displayed.

2. If N-1 is selected as the subsection:

• Grv-1 and Grv-2 (or all locations associated with N-1) would be displayed as location.

3. If Grv-1N-1 is selected as the location:

• Only those parts associated with that location would be displayed.

This approach moves down to a specific item. To look at all parts of specific types associated within a level, make a selection at the highest level desired and choose from the available parts.

For example, if HP is selected as the section and Key is chosen as the part, four keys will appear in the resulting listing.

If followed carefully, this system can become an extremely valuable tool. For instance, to list all the gaskets associated with main steam control valves (MSCVs), select MSCV as the section, and choose gasket as the nickname. All gaskets used within all MSCVs will be displayed, and the quantities required at each location will be listed. By producing a report based on this query, a bill of materials (BOM) of replacement parts is created and becomes the “shopping list” of items required. Comparing this list to the parts available shows part requirement needs.

Pre-Outage Planning and Bidding

2.2.7 Miscellaneous Turbine-Generator Exciter Parts, Bolts, Nuts, and Other