ML20214U352

Insp Repts 50-327/87-28 & 50-328/87-28 on 870504-06. Violations Noted:Hanger Design Loads Exceeded Snubber Capacity

ML20214U352
Person / Time
Site:	Sequoyah
Issue date:	05/21/1987
From:	Jape F, Lehanan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20214U325	List: ML20214U322 ML20214U332 ML20214U352
References
50-327-87-28, 50-328-87-28, NUDOCS 8706110152
Download: ML20214U352 (5)

See also: IR 05000327/1987028

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Report Nos.: 50-327/87-28 and 50-328/87-28

Licensee: Tennessee Valley Authority

6N 38A Lookout Place

1101 Market Street

Chattanooga, TN 37402-2801

Docket Nos.: 50-327 and 50-328 License Nos.: DPR-77 and DPR-79

Facility Name: Sequoyah 1 and 2

Inspection Conducted: May4-6,198J

Inspector: A c- f/b[J')

J. J. Lenahan ~/

( Date Signed

Approved by: .. . /WL ' f(64fl_. Tb

F. Jape, Sectio'n Chief Date Signed

Enginerring Branch f/

Division of Reactor Safety

SUMMARY

Scope: This routine, announced inspection was conducted in the areas of

followup on licensee action on previous inspection findings and a licensee

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identified item (LER).

Results: One violation was identified - Hanger Design Loads Exceeded Snubber

Capacity, Paragraph 3.b.

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8706110152 870604

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REPORT DETAILS

1. Persons Contacted

Licensee Employees

• S. Anthony, Licensing Engineer

G. S. Boles, Mechanical Maintenance Supervisor

• C, R. Bryant, Power Plant Maintenance Specialist

R. Landis, Construction Engineer, Modifications

R. C. Murray, Engineering Aide, Mechanical Maintenance

• L. M. Nobles, Plant Manager

• R. W. Olson, Modifications Manager

NRC Resident Inspectors

M. Branch

P. E. Harmon

K. M. Jennsion

• Attended exit interview

2. Exit Interview

The inspection scope and findings were summarized on May 6,1987, with

those persons indicated in paragraph 1 above. The inspector described

the areas inspected and discussed in detail the inspection findings. No

dissenting comments were received from the licensee. The following new

item was identified during this inspection.

Violation 328/87-28-01, Hanger Design Loads Exceeded Snubber Capacity.

The licensee did not identify as proprietary any of the materials provided

to or reviewed by the inspector during this inspection.

3. Licensee Action on Previous Enforcement Matters

a. (Closed) Violation Item 327, 328/86-24-01, Inadequate Procedure and

Lack of Records Pertaining to Functional Testing of Mechanical

Snubbers. The licensee's actions to correct this violation are

stated in their May 29, 1986, response to to NRC Region II. To

correct this violation, the licensee *evised Surveillance Instruction

(SI) 162.2, Snubber Functional Testing (Hydraulic and Mcchanical), to

describe the test method, criteria, and documentation requirement for

activation testing of mechanical snubbers. The inspector examined

procedure SI-162.2 and verified that the revisions were incorporated.

Violation 327, 328/86-24-01 is closed.

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b. (Closed) Unresolved Item 328/86-24-02, Load Ratings of Mechanical

Snubbers. Review of quality records during an inspection conducted

on March 18-21, 1986 (See Inspection Report Number 50-327,328/86-24),

disclosed that the the same size mechanical snubbers had different

load ratings, depending on the date of the manufacture. These

snubbers were designated as either Pre-NF or NF snubbers. The Pre-NF

snubbers have lower design load ratings. In order to evaluate this

problem, licensee personnel performed a walkdown inspection and

identified all Unit 2 pipe supports with pre-NF snubbers. The

location, size, and rating of the Unit 2 pre-NF snubbers were

tabulated and submitted to TVA Office of Engineering desiga personnel

for evaluation. The inspector reviewed the results of the engineering

evaluation during an inspection conducted November 12-14, 1986 (See

Inspection Report No. 50-327, 328/86-67). Four supports were

identified during the engineering evaluation where the design loads

exceeded the capacity of the installed pre-NF snubbers. These

snubbers affected pipe support numbers 2 RCH-184, 2 AFDH-229,

2 CVCH-154, and 2 CSH-457. The inspector examined the revised

hanger sketches for these supports which showed the details for the

replacement of the pre-NF snubbers with new NF snubbers that meet the

current updated design loads. The inspector also examined Field

Change Request (FCR) 4644 which was written to modify the revised

hanger sketches for hanger numbers 2 CVCH-154 and 2RCH-184. The

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inspector examined support numbers 2 AFDH-229, 2 CSH-457, 2 CVCH-154

and 2. RCH-184 and verified that new snubbers had been installed as

required by the revised hanger sketches and FCR 4644. During the

field inspection, the inspector also examined various snubbers

installed on safety-relating piping systems in the Unit 2 containment

- building. These snubbers included pre-NF snubbers installed in

hanger numbers 2 RCH-183, 2 CCH-175, 2 CCH-201, and 2 FDH-243. The

inspector verified that these pre-NF snubber were included in the

tabulation of pre-NF snubbers evaluated by the Office of Engineering.

The fact that undersized snubbers had been installed in four

safety-related pipe hangers was due to inadequate design drawings

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for these hangers. This problem was identified to the licensee as

a violation. Unresolved Item 328/86-24-02 is closed and upgraded to

Violation Item 328/87-28-01, Hanger Design Loads Exceeded Snubber

Capacity.

c. (0 pen) Unresolved Item 327/86-24-02, Load Ratings of Mechanical

Snubbers. The licensee has initiated a field walkdown to determine

the locations of installed pre-NF snubbers in Unit 1. This work

has been put on hold pending the restart of Unit 2. This item

will remain open pending completion of the Unit 1 pre-NF snubber

evaluation and review by NRC Region II.

4. Unresolved Items

Unresolved items were not identified during this inspection.

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5. Licensee Identified Item (LER)

(Closed) LER (86-046), Personnel Error Resulting in Inadequate Ver'ification

of Snubber Drag Force Trending. The licensee reported to NRC Region II on

November 11, 1986, that a personnel error in calculation of increase of

snubber drag force since the last previously performed functional test

resulted in failure to identify six snubbers which had drag forces which

increased by. more than 50 percent since the last previously performed

functional test. Technical Specifications 4.7.9.e.3 and 4.7.9.f require

that an engineering evaluation be performed for nubbers which show an

increase in drag force of more than 50 percent s.nce the last functional

test of that snubber. The inspector identified this problem for four

of the six snubbers during a review of tests results conducted during

a previous inspection and identifiea it to the licensee as part of

Unresolved Item 327, 328/86-24-02 (See Inspection Report Nos. 50-327/86-24

and 50-328/86-24). The inspector examined the results recorded during the

1985 functional testing conducted on the six snubbers which experienced a

greater than 50 percent increase over the previous surveillance. These

results are summarized in the Table below:

TABLE

Measured Acceptance

Support Number Snubber Type Drag Force Criteria *

1-CCH-1044 PSA-10 45 330

1 FDH-204 PSA-10 90 330

1 SIH 109 PSA-10 60 330

1 SIH 110 S PSA-10 80 330

1 FPCH-486 PSA-3 45 132

2-SGBH-133 PSA-1/4 10 10

• Maximum acceptable drag force is 2.2 percent of snubber capacity.

Based on review of the data in the above table, all measured drag forces

were well within the licensee's normal acceptance criteria. Therefore,

this problem had no safety significant. The licensee's corrective actions

to prevent reoccurrence of this problem were to revise procedure SI-162.2

to clearly indicate the steps required to calculate the relative increase

in drag forces. However, this increase has no significance as long as the

measured drag force is less than the licensee's acceptance criteria which

is based on the allowable drag force calculated during performance of the

piping stress analysis. This portion of Unresolved Item 327, 328/86-24-02

is resolved by closecut of this LER. The inspector discussed this problem

with the licensee during the exit interview and informed the licensee that

the majority of Region II licensees have removed from their Technical

Specifications the requirement for engineering evaluation of a functional

test for an increase of more than 50 percent in drag force over a previous

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functional test when the most recent drag test results were less than the

licensee's test acceptance criteria. This analysis is still performed as

a trending function to prevent snubber degradation, but is not used as

test acceptance criteria. LER 86-046 is closed.

Within the areas inspected, no violations or deviations were identified.

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